Zoology for you: SYBSc Zoo II Notes : Agricultural pests chapters 1 to 3

UNIT 2 : Agricultural Pests and Their Controls

2.1 AN INTRODUCTION TO PEST

2.1 An introduction to Pest, types of pests

(agricultural, household, stored grain, structural, veterinary, forestry and nursery)

Introduction : Human civilization has been competing with insects, rodents, diseases, and weeds for survival throughout its history. In modern India scientific study of insects was undertaken only from 18th Century. In 1898 the historical announcement was made on the discovery that Anopheles mosquitoes were the carriers of the malaria.

Important institutions or organizations that contribute much for the plant protection in India are the Indian Agricultural Research Institute (IARI) which was the first established in Pusa in Bihar in 1905 and later shifted to New Delhi in 1937. Indian Council of Agricultural Research (ICAR) was established in 1929. The Division of Entomology was established in 1905 as one of the five major Divisions of the then Agricultural Research Institute located at Pusa, Bihar and later it was shifted to New Delhi. Eminent entomologists like H.M. Lefroy, T. B. Fletcher, H.S. Pruthi, S. Pradhan and K.N. Mehrotra laid strong foundation for basic and applied research in insect science.

After the realization of the harm, the pests are doing harm to human beings by carrying the diseases, the Plague Commission was established in 1905 and the Central Malaria Bureau was established in 1909 in New Delhi. The Government of India established a permanent Locust Warning Station in 1939 after experiencing the effect of locust cycle in 1926-32.

The acute food shortage after the World War II and the Bengal famine in 1943 resulted due to the failure of rice crop by a paddy disease (Helminthosporiumoryzae.) which drew the attention of Govt. to prevent the damage of crops by pests and diseases to various crops.

In 1946 the Government of India started the Directorate of Plant Protection, Quarantine and Storage .Plant protection schemes were introduced in different states from 1947 to look after the pest problems, to advise the Central and State Governments and to enforce quarantine laws for preventing the possible introduction of new pests from foreign countries along with imported materials.

The Commonwealth Institute of Biological Control (CIBC) established its Indian station in 1957 at Bangalore. The Project Directorate of Biological Control (PDBC), Bangalore established in 1993, is nodal agency in India for organizing biological control research on agricultural pests at the national level. PDBC was upgraded as National Bureau of Agriculturally Important Insects (NBAII) in 2009 in order to exploit the agricultural insect resources from various agro climatic zones.

In Andhra Pradesh, Central Plant Protection Training Institute was established at Hyderabad in 1966 mainly to train the personnel in plant protection. Later it was named as National Plant Protection Training Institute (NPPTI) and recently during 2008 renamed as National Institute of Plant Health Management (NIPHM).

National Centre for Integrated Pest Management (NCIPM) was established at Faridabad in 1988 to cater to the emerging plant protection needs of different agroecological zones of the country. Later it was shifted to New Delhi in 1995.

Plant Protection Measures for Pest Control

Early man caught the intruders by hand, killed them or cut away the infested parts of the plant and burnt them. These mechanical and cultural methods are followed till to date in pest management.

Crop Losses Due to Insect Pests

Insect pests cause huge losses ranging from 5 to 80% of even up to 100%. Acute food shortage following world war –II and Bengal famine (1943) due to failure of rice crop due to a paddy disease indicate the severity of the loss, caused by the pests and diseases. The insects in storage on an average consume and spoil an additional 4 million tonnes of grains every year .All this indicates the importance of plant protection by which we can save millions of tons of food grains which are otherwise eaten away by different pests. Losses due to insect pests in Indian agriculture are 23.3 per cent .One of the practical means of increasing crop production is to minimize the pest associated losses.

The attack of pest to the agricultural crops causes economic loss to farmer. According to Edwards and Heath (1964) the pest is said to be “Economic Pest” if any when it causes at least 5% or more loss to the crops. The amount of damage caused to a crop is called as “Economic damage”. The damage must be significant and of economic value. The lowest pest population density which causes damage is called as “Economic Injury Level”. This varies from crop to crop, area to area and season to season and depends on stage of pest insect e.g. Caterpillar or grub of insect is more destructive than adult in case of stem borers. Economic Injury Level (EIL) includes can be decided by calculating or considering following four parameters:

(i) The market value of the crop

(ii) The yield loss attributable to a unit number of insects.

(iii) The effectiveness of the control.

(iv) Cost of control

Stern et al., (1959) called the density of pest population at which control measures should be started to prevent increase in pest population from reaching the economic injury level is called as ‘Economic Threshold’.

2.1.1. Definition of pest:

The word ‘Pest’ derived from French ward ‘Peste’ and Latin term ‘Pestis’ meaning plague or contagious disease. Pest is any species, strain or biotype of plant, animal or pathogenic agent injurious to plants or plant products (FAO, 1990; revised FAO, 1995; IPPC, 1997).

An insect reaches the status of a pest when its number increases and inflicts significant damage. ‘Pest’ is defined as insect or other organism that causes any damage to crops, stored produce and animals. Pest is a general term used to describe any organism (usually insect or animal) that is harmful to our health and properties including crop and livestock. The term, in its broader sense also includes micro-organisms, parasitic plants and weeds. Pest can be defined as any organism (animal or plant) whose population increases to such an extent as to cause economic losses to crops or a nuisance and health hazard to man and his livestock or possessions will be declared as a pest. Pest is an animal that causes harm to humans, their crops, livestock or possessions. Organisms that cause trouble, annoyance or discomfort are also considered as pests. The term ‘pests’ virtually covers all harmful insects and related terrestrial arthropods. In fact, the word is frequently restricted to these although some other invertebrate and vertebrate animals may be pestiferous. However, whether an organism is a pest or not is a matter of opinion.

I. A pest is an organism which harms to man or his property significantly or is likely to do so (Woods, 1976).

II. Pest is any animal which is noxious, destructive or troublesome to man or his interests

III. A pest is any organism which occurs in large numbers and conflict with man’s welfare, convenience and profit.

IV. Pests are organisms which impose burdens on human population by causing
(i) Injury to crop plants, forests and ornamentals

(ii) Annoyance, injury and death to humans and domesticated animals

(iii) Destruction or value depreciation of stored products.

It has been suggested that an insect becomes an economic pest when it causes a yield loss of 5-10%. In any local pest complex, there are usually few major pests that are the most important. These cause most of the damage, and their control is urgently required. The most serious one of the major pests is often designated as the key pest. There are usually only one or two key pests in each agro-ecosystem. They usually have a high reproductive potential, and often a good survival mechanism. Generally some pests are found in abundance during a crop season (regular pests), while others may assume pest status occasionally in certain years (sporadic pests). Some pests normally cause negligible damage, but may become highly destructive if environmental conditions become favourable for them (potential pests).

Damage boundary is the lowest level of injury where the damage can be measured. Insect pests are divided into a) negligible 2) minor and 3) major depending upon the severity of damage caused on the plant.

Pests that cause less than 5% loss in yield, is said to be negligible. Insects which normally cause a loss ranging from 5 to 10% are said to be minor pests and those which cause a loss of 10% or more in general called as major pests.

Different Categories of Insect Pests

Pests are classified in many different ways. They are also classified according to their mode of feeding, such as leaf feeders, sap suckers, stem and fruit borers, root feeders etc.

The different categories of insect pests are

1. Regular pest: Occur most frequently (regularly) in a crop and have close association with that particular crop. E.g.: Chilli Thrips Scirtothrips dorsalis , brinjal shoot and fruit borer, Leucinodes orbonalis

2. Occasional pests: Here a close association with a particular crop is absent and they occur infrequently. E.g.: Rice case worm, Nymphula depuctalis castor slug caterpillar, Parasa lepida , mango stem borer, Batocera rufamaculata

3. Seasonal pests: Occur mostly during a particular part of the year, and usually the incidence is governed by climatic conditions. E.g.: Red hairy caterpillar on groundnut-June - July, Rice grasshoppers –June-July, Paddy climbing cutworms.

4. Persistent pests: Occur on a crop almost throughout the year. E.g.: Scales and mealy bugs on many crops, thrips on chillies, paddy stem borer.

5. Sporadic pests: Occur on a few isolated localities. E.g.: coconut slug caterpillar –Macroplectra nararia, Contheyla rotunda, Rice earhead bug - Leptocorisa acuta,, castor slug caterpillar-Latoia lepida

6. Epidemic pest: Occur in a severe form in a region or locality at a particular season or time only. E.g.: Rice hispa, Dicladispa armigera, rice leaf roller, Cnaphalocrocis medinalis

7. Endemic pest: Occur regularly and confined mostly to a particular area or locality. E.g.: Red hairy caterpillar Amsacta albistrigaon groundnut in Kurnool, Ananthapur, Kadapa, Chittoor, Srikakulam and Vizag districts, stem borers of rice, paddy gall fly in Warangal districts.

Pests can be placed into four main categories:

insects and closely related animals
plant diseases
weeds
vertebrates

Insect pest Classification based on morphological difference

a) Insect pests

b) Mite pests

c) Micro-organisms (pathogens)

d) Nematodes

e) Vertebrate pests

f) Molluscs

g) Weeds & parasitic plants

I. Classification based on nature, intensity or frequency of occurrence

a) Regular pest: A pest that occurs every crop season and causes yield losses.

b) Sporadic pest/Occasional pest: A pest that is irregular, occurs here and there or at random but occasionally causes problems.

c) Potential pest: A pest that could cause significant economic loss if allowed to establish.

d) Major pest: A more common and important pest

e) Minor pest: A pest that is not causing huge damage

II. Depending upon the importance, pests may be

a) Agricultural crop pest,

b) Stored grain pest,

c) House hold or Domestic pest,

d) Structural pest,

e) Veterinary or Medical pest

f) Forestry and Nursery pest or aesthetic

a) Agricultural Crop Pests:

The agricultural crops are infested by number of pests that cause severe damage. Pest comprises a large number of insects attacking the various crop plants. The immature stages or adults insects are either foliage feeders or saps suckers. These insects bear chewing and sucking type of mouth parts. They may be internal feeders or borers or sub-terranean inhabitants. The cabbage worms, semiloopers, potato beetles, etc., possess chewing type mouth parts. They chew and shallow the external parts of the plants. The important cereal and cash crops like jowar, bajara, wheat, cotton, sugarcane, etc. are attacked by pests like stem borer, shoot fly, Deccan wingless grasshopper, armyworms, flea beetles, aphids, leafhoppers mites, jowar midge fly, etc. While some insects i.e. blister beetle feed on pollens, petals of bajara etc. thus causing severe damage. Sugarcane is an important cash crop cultivated widely in Maharashtra. This single crop is infested by sugarcane stem borer, shoot borer moth, root borer, pyrilla, mealy bug, scale insects etc. The cutworms, leafhoppers, potato tuber moth, epilachna beetles, mites, aphids and thrips cause injuries to potato crop and vegetables in field as well as in the storage. The cabbage leaf miner and cabbage caterpillars spoil the cabbage crop seriously. The Rhinoceros beetle, mango stem borer, brinjal fruit borer, ber fruit borer infesting the variety of fruits in the field as well as in the storage. The Thrips, Aphids, flea beetles, etc. damage grapes, resulting to great economic loss; if not controlled properly. The pigeonpea and chickpea and other dicotyledons attacked by pod borer Helicoverpa armigera, semiloopers, aphids, leafhoppers etc. The rhinoceros beetles and chickoo moth cause damage to coconuts and chickoo. Thus, large number of pest organisms cause serious damage to many agricultural crops.

Agricultural Pests may have following direct or indirect effect on agricultural plants/crops as following

(a) Direct effect

The direct effect of pests is mainly due to their feeding on the crop plants, through biting, piercing or sucking mouth parts to feed on the crop accordingly.

(i) Leaf eaters like adults and nymphs, larvae of Zonocerus, caterpillar larvae reduce the leaf area and adversely affect the plant growth.

(ii) Stem borers and hoot flies make tunnels in the stem and disturb the conduction mechanism of the plant i.e. Antherigona in Maize, Disphya in coffee.

(iii) Some pests attack the buds at the growing points and prevent the branching and growth of the stem. i.e. Chilozonellus in Jowar and Earias in cotton.

(iv) In some plants, the pests causes the immature fruit fall i.e. Mango fruit fly, ridge fly.

(v) The pests attack the flowers and damage the crop e.g. Tassel beetle of Maize.;

(vi) In some plants like maize, black maize beetle, destroy the absorbing tissue of root leading inhibit growth. Some insects consume stored food, underground tubers, etc. affect growth i.e. potato beetle.

(vii) Number of sucking insects sucks cell sap from the crop plants in large quantities and results in loss of vigour of the plant. For example, Bemisia (white fly) on cotton, Aphids on many vegetable plants.

(viii) Some pest sucks sap from flower and reduces the seed setting i.e. coffee Lygus bugs.

(ix) Premature nut fall is seen in coconut because of coconut hug and scales insects’ causes premature leaf fall.

(x) Some sucking insect inject toxins into the host body which results in distortion, gall formation, necrosis of leaves, etc. in the host e.g. Lygus bugs in cotton.

(xi) The pink boll worm Dysdercus cingulatus sucks cell sap of cotton affecting vitality of plants.

(b) Indirect Effects:

(i) Agricultural pests effects, delay the crop maturity and harvest. These pests not only cause loss of production but also cause decline of qualify, nutritional value, discolouration and market value.

(ii) The insects cause damage also act as transmission agents to transfer the pathogenic fungi, bacteria or viruses which leads secondary effects on the crop plants. For example Platygasteri wasp transmit coffee leaf rust, viral diseases like mosaic virus disease and curling leaf of cotton.

b) Stored grain pest:

About 30 species of insect commonly infest food aid grain and grain products. Most insect pests are either beetles or moths. In addition to insects, the only other invertebrates that are commonly found in stored food are mites. These are difficult to see as they are often less than 0.5 mm long; unlike insects they have eight legs and lack both wings and antennae.

The stored food grains, seeds, fruits, nuts, etc. are infected by the internal borer insects in the Kothis, godowns and warehouses are most injurious of all insects. The borers can attack them, even during the harvesting stage in the farm land itself. Considerable losses both in quality and quantity of food grains take place in storage due to number of factors. Organisms like insects, mites, rodents, fungi and bacteria are directly responsible for causing loss in stored products. The storage of food grains has been a long practice with cultivators and traders and it is estimated that about 74Q% stored grains are lost every year due to stored grain pest in India.

Any stored or transported food commodity can be subject to attack by pests:

· Insects

· Rodents

· Birds

Food aid commodities in store are particularly vulnerable to attack by insects, rodents, and to a lesser extent by birds.

Insects that attack cereals and grain pulses are usually divided into two groups:

Primary pests

Primary pests attack and breed in previously undamaged cereal grains and pulses. They also feed on other solid but non-granular commodities, but they are rarely successful on milled or ground foodstuffs. Primary pests are usually more destructive than secondary pests, especially in short-term storage.

Secondary pests

Secondary pests are able to attack only materials that have been previously damaged either by other pests (primary pests) or by poor threshing, drying and handling. They also attack processed commodities such as flour, pulses and milled rice, where they may form the majority of insects present.

Effect of stored grain pests:

The grain weevils (pulse beetle, rice weevils), moths Red rust flour beetle, etc. cause a major damage to stored cereals (wheat, rice, bajara, barley, corn, oat, millets, etc.) and pulses (lentils, peas, beans, gram, etc.) respectively. Mainly the insects spoil the stored food grains and render them unfit for human consumption and sowing purposes.

Pest infestation compromises the characteristics and self-life of commodities. It can impact the safety of food products via the transmission of zoonotic diseases (e.g. Leptospirosis from rodent urine or droppings). Pests can damage packaging materials (holes, gnawing, chewing) and result in major losses of food that is eaten, spoiled or contaminated by them. Moreover, pests may provoke severe damages at the warehouse premises. For example, they may cause fire hazards by gnawing of the electrical wires.

c) Household Pests:

Pests that infest dwellings are commonly referred to as household pests (insects). Household insects are direct concern to man, his possessions and his immediate environment.

Insects such as roaches, crickets, houseflies, fruit flies, weevils, ants (red and black), and silver fish, etc. which contaminate eatable food and spoil it or transmitting disease causing agents are commonly placed under this group. The insects like cloth moths, carpet beetle, furniture beetles cause damage to property (human-possessions) is also belongs to household pest. Thus, all types of insect which are unwanted guests in the human dwellings which cause damage to human holdings and his health are called as household pests.

ANTS

Small red ants: Monomorium destructor; M. criniceps; M. gracillinum; M. indicum

Large black ants: Camponotus compressus

Red odoriferous ants: Myrmecaria brunnea

Safari ants: Dorylus labiatus

Ants eat and carry food material and create nuisance in the kitchen and house where they crawl in the eatables and other items of use. Some species also leave formic acid odour in the eatables. Because of excessively large number they manage to carry large about of food grains from kitchen to their nests.

Control. Ant pans should be used to protect eatables. Baiting with thallous sulphate and thallium sulphate or sodium arsenate kills ants. Nest should be located and fumigated with carbon bisulphide. Dusting of the floor and ant trails with 5% dust of chlordane, BHC, diazinon and linden is an effective method to get rid of them.

TERMITES

Termites eat away any wood article, paper, plants and animal products. They destroy doors, windows, cupboards, almirahs etc.

Control. Pressure impregnation of creosote, coal tar, zinc chloride, mercuric chloride, sodium fluosilicate, dieldrin etc. helps to get rid of them. Wood can be immersed in the insecticide solution for 24 hours to make it termite resistant. Soil treatment with dieldrin or BHC before construction of house should be done to keep termites away from the buildings. Termite nests can be destroyed by pouring in them a mixture of dieldrin and kerosene.

FURNITURE BEETLES

Dinoderus ocellaris

Sinoxylon sudanicus (Bostrychidae)

Stegobium paniceum

Anobium punctatum

Heterobostrychus aequalis

Lycus africanus

They are also called powder-post beetles in India. Prothorax covers the deflexed head, antennae are clavate, generally 11-segmented and elytra completely cover the abdomen.

Damage. Both adults and grubs damage wood reducing it into powder. They cut galleries inside wood and make it week so that it breaks easily with slightest of pressure.

Control. Treatment of wood with copper sulphate or zinc chloride before making furniture prevents the damage. Infested wood can be dried at 80-90 degrees to kill all stages of the insects inside. Fumigation by inserting cotton swabs soaked in chloroform or methyl bromide into the galleries also kills the larvae and adults inside. Regular varnishing and polishing of furniture is a good preventive measure.

SPIDER BEETLES

Ptinus tectus; P. hirtellus; Niptus hololeucus (family Ptinidae)

These beetles are 2-4 mm long and possess long legs and antennae; the 11-segmented antennae are placed closely in front of legs. Body is covered with short hairs. They feed on a variety of stored products.

SILVER FISH

Ctenolepisma

Lepisma saccharina

Thermobia domestica (fire brat)

They are silvery grey dorso-ventrally flattened stream-lined creatures that are about one cm in length. Tip of abdomen possesses three long thread-like cerci. They are quick in movement and crawl on the walls and hide behind pictures.

Damage. Silver fish are commonly found on walls and feed on starch, cloths, fabric, book-binding, pictures etc., which produces holes in papers pictures and books. Dark and damp places are preferred and hence their population goes up during rainy season. Life cycle can take up to 2 years and longevity of adults is 1-3 years.

Control. Spraying carbamates such as carbaryl, baygon etc. kills them quickly. Dusting with 5% carbaryl is also effective. Baits can be prepared by mixing oatmeal and sodium fluoride, paris green or white arsenic and sugar. However, regular cleaning and ventilation for drying is an effective method to bring down their population.

CARPET BEETLES (family Dermestidae)

Dermestes lardarius; D. carnivorous; D. ater; D. maculatus; D. vulpinus;

Anthrena fasciatus; A. vorax (=flavipes); A. pimpinella; A. fasciatus are called spotted carpet beetles as they possess bands of different colour. Larvae are reddish-brown in colour, 6.0 mm long, hairy with long hairs on the posterior side.

Attagenus pellio; A. piceus, are called black carpet beetles. Larvae are hairy, golden-brown in colour and 1.0 cm long. They are small beetles with oval body densely covered with hairs, 2-5 mm long and with a small head having a median ocellus. Antennae are short and capitates. Tarsi are 5-segmented. Larvae are dark brownish to black and possess long brownish hairs and hence nick-named “Woolly bears”. Their cast skin is also hairy.

Damage. Both larvae and adults bite holes in clothes, carpets, woollens, padding of furniture, curtains, fur etc. They also attack museum specimens, stuffed animals, dried meat etc.

Control. Fumigation with paradichlorobenzene and naphthalene and spray of stainless insecticides such as perthane and methoxychlor or dusting the corners with dieldrin or BHC helps to eradicate them. Control measures are particularly important to be undertaken during summer and rainy months.

CLOTHES MOTHS

Tinea pachyspila; T. pellionella;

Trichophaga abruptella;

They are small moths of dull colour, having a wing span of one centimetre and frequently fly about in houses. Larva is 2 cm long, enclosed in a greyish silken case which it drags along while crawling on the walls, floors etc. Pupation also takes place inside the case, pupal period being about 10 days. Under warm and moist conditions the entire life cycle is completed in six weeks.

Damage. Larva attacks wool, hair, feather, fur, dead insects, dried animals, fish meal, milk powder, leather etc.

Control. Clothes and other fabrics should be thoroughly dried up and then dusted with insecticides. Fumigation with paradichlorobenzene, naphthalene or camphor and spray of insecticides, e.g. perthane, methoxychlor, malathion etc. effectively kills the larvae as well as adults.

CRICKETS

Acheta (=Gryllus) domestica, more common in the field but also found in houses, is dark brown in colour. Both sexes are winged. Cerci are long and hind wings also pointed forming a tail-like structure. Gryllodes sigillatus, dull and straw-coloured with brownish patches on body and legs and with a brown streak on the head. Female is wingless and male winged. Abdomen has cerci in both sexes and female has a long ovipositor in the middle.

Gryllotalpa Africana, the mole cricket has fore limbs modified for digging and hind legs adapted for jumping. It lives in burrows and feeds on the roots of plants. It comes out in the night and is sometimes attracted to lights.

Crickets are found in dark and damp places in kitchens, crevices and cracks in the houses. They are nocturnal and feed on a variety of food materials and damage clothing. They are omnivorous and hence damage almost any article of use in the houses. They also stain the articles and clothing with faecal matter. In the night they annoy by making noise. They breed in rainy season and autumn and lay eggs in damp cracks and crevices. Eggs hatch in 8-10 days. Nymphal period is about 6 weeks during which they undergo 8-9 moults.

Control. They can be controlled by spraying carbamates, Baygon, lindane, malathion, endosulfan etc. Maintenance of hygiene and dry conditions in homes keeps them away. They can be trapped in large numbers in a jar containing starchy sweet vinegar, mixed with insecticide, white arsenic or paris green.

BOOK LICE

Liposcellis transvalensis; L. divinatorius

They belong to order Psocoptera and prefer to live in dark, damp places in houses libraries and museums. They are tiny pale whitish insects, 1-2 mm long, soft bodied, without wings and cerci. Antennae are short filiform and hind femora are enlarged. They lay extraordinary egg that measures one-third of the body length. In the night they make ticking sound due to which they are also called “death watch”.

Damage. They are omnivorous and feed on fungi, stored products, book binding etc. They thrive on animal and vegetable debris, paste, fungi, glue, dry botanical and zoological specimens etc. They have been recorded to seriously damage tea packed and stored in damp godowns in Assam. They are particularly abundant in the old unused books, whose paper and binding they damage.

Control. They can be controlled by dusting the places with any insecticide. Fumigation with sulphur dioxide or HCN gas or ethyl acetate kills them quickly. Thorough cleaning and drying or heating of infested articles up to 60^oC gives relief in mild infestations.

d. Structural Pests:

Under this category the pest insect mainly destroy man made articles, constructions mainly composed of cellulose material. Structural pests are those harmful insects which cause damage to wooden frames, doors, furniture, fencing posts, library books, stored papers, cardboards, and all other wooden articles and components of buildings are referred as structural pests.

The termites (i.e. white ants) are colonial and social insects, feed on cellulose, mean while damage wooden material in variable form. Silver fishes food on starch material and ghee, thus damaging book bindings, wall papers, photographs and all kinds of adhesive labels. Cloth moths and carpet beetles can also be damage cloths, carpets as structural pests.

e. Veterinary pest : (Domestic Animal Pests)

The insects which cause damage to domestic animals like goats, chicken, horses, cattle, etc. And blood sucking insects like fleas, lice, bugs, mosquitoes, stable flies as ectoparasite are the examples of domestic animal pests. A biting lice like Mallophaga cause irritation and loss of flesh in poultry farms. Tabanid flies, horn flies suck the blood from cattle and horses. Both flies cause serious stomach disturbances in horses. Grubs of OX-warble flies cause loss of flesh in cattle and can cause damage to the leather by cutting holes in the skin.

f. Forestry pest: forestry and nursery:

The adult or larva or grub of pest insect enter into the plant and cause deformations in the structure and function of different organs of the forest and nursery plants and trees i.e. stem borers enter stem / shoot causes tunnelling inside and swelling. Leaf roller and leaf cutter cause severe deforestation. The sap suckers such as plant bugs, aphids and Thrips suck plant juice of nursery plants which inhibit the photosynthetic activity. E.g. Bark beetle destroy the timber in the forest, the termites damage the timber logs even after leaving the forest. Gall insects cause swelling, bark feeder destroy surface of stem.

To be able to control these pests, we need to know the following:

· the common features of pest organisms.

· characteristics of the damage they cause.

· the biology and development of the pest.

Questions:

1. Define the term pest, economic pest, economic damage, economic injury level.

2. Give different types of pests

3. Give the direct and indirect effects of agricultural pest.

4. Write short notes on:

i. Agricultural pest

ii. Stored grain pest

iii. Pest of Forest and Nursery

iv. Veterinary pest

v. Household pest

vi. Structural pest

Self Study Questions with answers

1. What are some examples of the characteristics of a pest?

2. What percentage of insects is considered pests?

3. Name the three main body parts of an insect.

4. Give three examples of pests that look like insects, but are not.

5. What causes plant disease?

6. Name four organisms associated with plant disease.

7. Give three examples of situations in which weeds are pests.

8. Name the three types of life cycles that plants have.

9. What does the term “vertebrate” mean?

10. Give two examples of a vertebrate pest.

Answers to Self Study Questions -- Pests

1. Anything that injures, spreads disease, or competes with humans, domestic animals, or feed crops.

2. About 1% of insects are considered pests.

3. Head, thorax and abdomen.

4. Centipedes and millipedes, crustaceans, and arachnids.

5. Diseases are caused by biological agents called pathogens.

6. Bacteria, fungi, viruses, and nematodes.

7. Causing skin irritation, poisoning, hindering fishing, clog drainage areas, etc.

8. Annuals, biennials, and perennials.

9. Animals with a jointed backbone.

10. Rodents and some birds.

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2.2 MAJOR INSECT PESTS OF AGRICULTURAL IMPORTANCE

(Study of following Major Insect Pest of Agricultural importance with reference to Marks of identification, life cycle, nature of damage and control measures)

a) Jowar stem borer

b) Red cotton bug

c) Brinjal fruit borer

d) Mango stem borer

e) Pulse beetle

f) Rice weevil

a) Jowar stem borer

Scientific Name: Chilo partellus S.

Class — Insecta

Order – Lepidoptera

Family - Pyralidae
Genus - Chilo
Species — zonellus = partellus (Swinhoe)

Jowar is the most important stable food crop of the Maharashtra state. Besides being stable food crop of the people, it also supplies very good fodder for the cattle. It is cultivated in Kharif, Rabi and also in hot weather. Jowar stem borer is one of the major pests of jowar.

· Distribution:

It occurs throughout India. The jowar stem borer is commonly called as pink borer or spotted stalk borer because of dark spots on the body of larva.

· Marks of Identification:

The Moths - medium sized with 3 cm wing span, its forewings are straw or light brown or yellowish grey in colour with numerous shining brown spots on the margin and hind wings are white and papery. The hind wings are whitish. Caterpillar or (Larvae) - dirty white, brown head with mandibulate type of mouthparts, many dark spots on the body, 12- 20 mm in length and shows four broad and patchy strips on the body.

· Host plants:

Although principle hosts are Jowar and maize, it has also been recorded on Sugarcane, Ragi and certain grasses.

· Life history:

a) Eggs - A female moth after matting lays about 50-300 eggs in clusters arranged in two rows on the under surface of the leaves during April-May. The eggs are oval creamy white in colour.

b) Caterpillar- Larvae- The eggs hatch into the young caterpillar in about six days of incubation period. The young caterpillar feeds on tender leaves for a day or two and bores into the central shoot. The larval period last for about 3-4 weeks and have normally five moults. Before pupation larva prepare a hole on stem at ground level for the moth to escape / come out.

c) Pupa: Pupation takes place inside the stem and it last for about 7-10 days.

d) The adult lives for 2-4 days. Adult longevity is 2-4 days.

The pest is generally active from June to November and about four generations are completed in a year. The pest hibernates in the larval stage in stubbles during unfavourable conditions.

Life cycle of Chilo partellus

Fig.2.2.1. Life cycle of Jowar Stem Borer Chilo zonellus = partellus

Fig.2.2.2 Schematic Life cycle of Jowar Stem Borer Chilo zonellus

Life cycle: completed in 6-7 weeks. About 4-5 generations are completed in a year.
Carry Over: The pest hibernates in the larval stage in stubbles. Seasonal occurrence: The pest is generally active from July to November. The infestation is more on rabbi & summer crops.

· Nature of damage:

On hatching from the eggs, the larvae initially feed on the tender leaf whorls causing series of small holes in the leaf lamina and attack all parts of jowar plant except the roots. The larvae on entering the leaf, whorl and cut the leaves, which on emergence manifest characteristic pin holes, shoot holes and longitudinal streaks. At times the growing point is cut which results in drying of the central shoot, causing the death of central shoot and commonly known as “dead-hearts”. The larvae after entering the stem, feed on the tissues (pith) and tunnels or galleries are formed.

Fig.2.2.3. Death of central shoot- Dead-hearts

· Control Measures: Management Practices: Preventive and curative measures.

Preventive:

Collection and destruction of stubbles after the harvest of crop to kill hibernating larvae
Increase the seed rate to compensate the loss.
Follow proper crop rotation (with non host crop).
Use of light traps.

Curative: Cultural Practices:

Removal & destruction of affected shoots along with the larvae.
Hand picking or light trapping of adult moths and collection of their eggs for destruction.
Burning of stubbles and trash which harbour borers and act as source of infestation for the next crop.
Changing the sowing and harvesting timing reduces infestation.
Crop rotation is another cultural practice that does not allow the pest of one crop to survive next year for lack of its host.
Growing resistant varieties of jowar like CHS-7, CHS-8, Indian sorghum types IS-5285, 5566, and 5613.

Chemical Method:

1. For the Chilo on jowar a spray of 0.05% linden or 0.1% endosulfan on 15 days
old plants has been found. Second application may be followed after another fortnight with 1.0% linden or 4% endosulfan granules @ 10kg/ha, when 10% plants are infested. A third application with 0.2% carbaryl spray may be carried out, if found necessary.

2. If the crop infestation is noticed, dusting of crop in the early stage with 10% BHC at the rate of 25 kg per hectare or spraying the crop with 350-400 ml of aldrin or
dieldrin in 200 litre of water helps to control the pest.

Biological Method:

1. Only the egg hymenopteran parasitoid, Trichogramma minutum is employed as egg parasite.

2. If the caterpillars are outside the stem particularly on leaves then Apanteles flavipes and Bracon brevicornis as larval parasites can be used to control.

3. The lady beetles, Coccinella septempunctata and Menochilus. Sexmaculata have been recorded predating on early stages of the larvae of this pest.

Economic Importance:

It is one of the major pests of Jowar. This pest is generally observed in the early growth of the crop and even after the earhead formation. This pest is active throughout the year but the infestation is more noticed on rabi and hot weather crops. The hybrid varieties are more susceptible to this pest. The infestation is noticed till harvest and the grown up plants when damaged lose their vigour and put forth week ears. The infestation is more pronounced on rabi and hot weather crops.

b) Red Cotton Bug

Scientific name : Dysdercus cingulatus Fab.

Common Name : Red cotton bug

Local Name : Tambade dhekun

Scientific Name : Dysdercus cingulatus Fab.

Class : Insecta

Order : Hemiptera

Family : Pyrrhocoridae

Genus : Dysdercus

Species : cingulatus = koenigii (Fab)

Pest Category : Lint Stainers

· Distribution: The red cotton bug has wide distribution; it is a minor pest in cotton growing region of northern India particularly Punjab and Uttar Pradesh. This pest also occurs throughout the Maharashtra state but is minor importance. It is commonly known as a “cotton stainer”.

· Marks of Identification:

Egg: Eggs are laid in moist soil or in crevices in the ground. They are spherical and bright yellow in colour.

Nymph: Nymphs are red coloured with black median dorsal spots on the inter-tergal membrane of 3/4, 4/5 and 5/6 abdominal segments. There is a pair of white dorsal spot on each of the third, fourth and fifth tergal plates on the abdomen. The nymphs are smaller than adults and are wingless.

Adult: Adults are 12-15 mm in length and have deep red legs and antennae. The females are Longer (15 mm) than the males (12 mm). The membranous portion of the forewings and the eyes are black in colour. There is also a black spot in each forewing. A series of white transverse bands are present on the ventral side of the abdomen. T h e transverse bands along the posterior margins of each thoracic and abdominal sterna, the collar behind the head and the spots at the base of the head are white in colour. Mouthparts are adapted for piercing and sucking. They form a straight beak or rostrum.

Fig.2.2.4. Red cotton bug Adult

· Host Plants : Cotton, bhendi, ambadi, hollyhock and several other malvaceous plants.

Life History :

i) The eggs are laid by the female under the soil in cracks and are covered with loose earth or with small dry leaves. Eggs are round and light yellowish about 1.2 mm in length. Each female is capable of laying between 100-130 eggs. Egg period lasts 7-8 days.

ii) Eggs are hatched in to active 1mm long red coloured nymphs. They resemble the adult with the adult except size and absence of wings. Nymphs after hatching are wingless with their abdomen red with central row of black spots and row of white spots on either side. Nymphal period lasts for 5-7 days. Nymphs pass through five moults with wings developing from the third instars and attaining full form after the fifth.

iii) The development is completed in 50-90 days. Males are smaller than the females and the swollen abdomen can differentiate females from males. In winter the longevity of the adult is about 3-months but in summer it is varied.

iv) Pest breeds on cotton from August- November; takes shelter under leaves or debris from December-middle of March and feeds on bhendi from April-July.

v) Life cycle: completed within six to eight weeks.

Fig.2.2.5. Schematic Life cycle of Red cotton bug Dysdercus cingulatus.

· Carry over: Pest breeds on cotton from August- November; takes shelter under leaves or debris from December-middle of March and feeds on bhendi from April-July. Red cotton bug appearance on cotton is after the commencement of the first open boll in the cotton fields.

· Nature of Damage:

Adults and nymphs suck the sap from leaves, green bolls and seeds of partially opened bolls. Vitality of the plant is lowered, in general. Affected bolls open badly with their lint stained with the excreta or body juices. Quality of the lint is affected and the attacked seeds become unfit for either sowing or oil extraction. Boll rot is caused by the secondary infection due to bacteria wherein rotting of the entire contents of the boll occur following the initial discolouration of the lint to yellow or brown. The lint is stained by the excreta of bugs or by their body juice as they are crushed in the ginning factories, so named cotton stainer.

Control Measures:

Cultural Practices

1. Cotton field should be ploughed to expose eggs to sunlight.

2. Insects should be handpicked and killed in kerosene water.

3. The crops of bhendi should be sown as trap crop and pests collected there, should be destroyed.

4. Moistened cotton seeds should be hanged up at different places in the field where bugs congregate, they may get killed in the kerosene water.

Chemical control

1. Spraying of Malathion 0.05% is effective to control the pest.

2. Spraying of 1 liter endosulfan 35% EC, 0.25 liter phosphamidon = 100% EC or 1 liter Fenitrothion 100% EC per hectare is very effective or reduce pest population.

c) BRINJAL FRUIT BORER:

Scientific name: Lucinodes orbonalis Guen

Class: - Insecta

Order: - Lepidoptera

Family: - Pyralidae

Genus: - Lucinodes

Species: - orbonalis

· Distribution:

India, Bangladesh, Malaysia, Thailand, Burma, Srilanka, Laos, South Africa, Congo. It is a major and regular pest of brinjal causing damage to even 30 -50% of fruits or more. Most destructive pest of brinjal, found throughout the country. It is active throughout the year, except in severe cold weather in North India.

· Marks of Identification

Ø The moths are medium sized. Wings expanse 22-26mm. Full grown larva is light pink measuring about 12mm long.

Ø Fore wings are white having conspicuous black and brown patches and dots

Ø Hind wings are opalescent with black dots.

Ø Eggs are flattened, elliptical, laid singly on leaves, shoots, flower buds and occasionally on fruits.

Ø Full grown caterpillars are light pink in colour.

Fig. 2.2.9. Brinjal Fruit and shoot borer Adult Lucinodes orbonalis

· Host plants

Besides brinjal, the pest is also known to infest potato, bitter gourd, pea pods, cucurbits etc. and other solanaceous crops.

· Life history

a) A female lays on an average 250 eggs on leaves, shoots or sometimes on fruits. Incubation period is 3-5 days, larva become full grown in 7-15 days.

b) The full grown larva comes out and pupation takes place in boat shaped cocoons on the plant itself. The pupal period lasts about 7-10 days. Adults live for 2-3 days.

c) Life cycle is completed in 25-40 days. The duration of development of life stages depend on temperature, in winter when there is low temperature it requires more days and in summer when there is increase in temperature there is decrease in duration of developmental period.

Fig.2.2.10. Shoot and fruit Fig.2.2.11.Larva of Brinjal fruit borer

borer adult moth

Fig.2.2.12. Schematic Life cycle of Brinjal fruit borer

· Nature of damage

Ø Infestation starts after few weeks of transplantation. In young plants caterpillars bore into petioles and midribs of large leaves and young tender shoots and feed on internal tissue.

Ø Faecal pellets are seen at entrance hole.

Ø When the infestation is on shoots, they bend down and whither, affected leaves and shoot wither and dry.

Ø The larvae also attack the fruits making their entry under the calyx when they are young, leaving no visible signs of infestation. The pinkish larvae make zigzag tunnels in the fruits which are holed.

Ø At later stage of growth, caterpillars bore into flower buds and fruits, sometimes from under the calyx, when no visible symptoms are apparent.

Ø Damaged flower buds are shed and fruits show circular holes.

Ø The large holes seen on fruits are usually the exit holes of the caterpillars.

Ø The content of vitamin C in the fruits of the brinjal is found to be reduced.

· Control measures

Cultural practices

Ø Continuous cropping of brinjal and potato should be avoided and resistant varieties if available should be cultivated,

Ø Continuous cropping of the brinjal leads to more infestation and hence should not be indulged in.

Ø Brinjal with long, narrow fruits are less susceptible to attack and, therefore, this variety should be preferred than other varieties. Use of Resistant/Tolerant varieties in endemic zones.

Ø Removal and destruction of withered and dried shoots help in arresting the spread of the pest.

Ø The use of light traps containing killing solution like kerosene at the base of container during night times can be used to kill adult moth of pest insect.

Chemical Control

· Spraying with 0.05% monocrotophos 36 WSC or 0.2% carbaryl or dusting with 10% carbaryl 3-4 weeks after transplantation subsequent application 15 days thereafter controls the pest effectively.

· Endosulfans, Fenvalerate, Cypermethrin or Deltamethrin are also recommended.

Synthetic pyrethroids in hot weather are less effective.

One or two of the following insecticide can be used with proper care and counselling with agricultural expertise for control of brinjal fruit borer.

Name of the Insecticide	Quantity in one liter of water
Carbaryl 50 w/p	4.0 g
Endosulfan 35EC	3.0 ml
Malathion 50 EC	2.0 ml
Phosalone- Zolone 35 EC	2.1 ml
EC = Emulsifiable Concentrates; w/p = Wettable Powders

Biological control

The Braconid wasps (Bracois chinensis) and Ichenumoid wasps (Trathela flauoorbitais) parasitize the caterpillars of brinjal fruit borer.

Carry over: The pest is active throughout the year.

· Economic Importance

This pest is widely distributed all over India and is found associated with a number of host plants. It is one of the most serious pests of brinjal fruits and plants. Up to 70 per cent loss is caused to brinjal by this pest.

d) MANGO STEM BORER

Class — Insecta

Order — Coleoptera

Family — Cerambycidae

Genus — Batocera

Species — rubus (Linnaeus, 1758)

Synonyms: Batocera albofasciata De Geer, 1775; Batocera albomaculatus Retzius

Common names: rubber root borer; lateral-banded mango longhorn; mango longhorn beetle (en), asiatischer Kautschukbaumbohrer (de), panterboktor (nl)

Distribution:

In its native area in Asia B. rubus is seldom a serious pest. It is present in: America: no data
Asia: Bangladesh, Brunei Darussalam, Cambodia, China, India, Indonesia, Lao, Malaysia, Myanmar, Pakistan, Philippines, Taiwan, Thailand, Vietnam
Africa: no data
Europe: intercepted in France (2011, Nanterre on a single bonsai plant-Ficus microcarpa), incursion in Italy (2012).

It is very common in Gujarat, Maharashtra, Andhra Pradesh and Uttar Pradesh.

Marks of Identification:

The adult beetles are well built, large sized, measure about 4.5- 5 cm long in length and brownish yellow/grey coloured. It has orange yellow spots on thorax and has hard forewings (elytra); lateral spines on the prothorax and long antennae and legs. The grubs are large, yellowish white in colour, fleshy in appearance and measures about 100 x 18 mm. with black head bearing strong mandibles.

Fig.2.2.16. Adult beetle Fig.2.2.17. Grub (larva)

(Mango stem borer- Batocera rubus L.) (Mango stem borer)

· Host Plants: Batocera rubus is known to attack broadleaf trees and woody plants. In Europe it was intercepted on bonsai trees. B. rubus is a large wood borer that has been recorded on rubber tree Hevea brasiliensis in Thailand, particularly on trees damaged by other causes such as fire and lightning. Larvae (6-8 cm) also feed on freshly felled timber. The other recorded major hosts: bread fruit trees Artocarpus altilis, A. heterophyllus, fig Ficus carica, mango Mangifera indica In India this pest is found on the planted plants like mango, fig, rubber and jack.

· Life history :

i. The female beetle deposits single egg under the loose bark or in a diseased part of trunk or in the crevices of stems.

ii. After the completion of incubation period of 14 to 17 days the egg hatches out.

iii. The grubs on hatching penetrate into the stem or even the roots feeding on the woody tissue and make tunnels. The larval stage last for 3 to 6 months; then they pupate in the stem and remain in the pupal stage for 3 to 6 months over winter and the adults generally emerge during the monsoon.

iv. The life cycle may extend for period of 1 – 2 years.

Fig.2.2.18. Schematic Life cycle of Mango stem borer Batocera rubus.

· Nature of damage:

The milky white grubs make zigzag galleries beneath the bark and tunnel into the trunks or main stems. As a result of feeding on the internal tissues, the attacked branches and stem die and wither away. Sometimes, frass and masses of refuse exude may be seen on the opening of the bored holes. In severe cases of attack, the branches may collapse and the tree may die.

Fig.2.2.19. Nature of damage by Mango stem borer- grub

· Control Measures:

To prevent infestation regular cleaning, checking and applying salt, lime or kerosene to the stem can reduce the chances of infestation.
The population of grubs and pupae of stem borer can be reduced by cutting and destroying the infested branches.
In tunnels or holes kerosene or other oil if injected can kill the grubs to some extent.
The best way to control the grubs is to just inject borer solution (i.e. 2 parts of carbon disulphide + one part of chloroform and cresol) in the holes after which it should be closed by mud.
Pest population can also be effectively reduced by injecting 0.05% spray liquid of the following insecticides into the borer holes of tree or branches.

Name of Insecticide	Quantity (ml.) / liter of water
Chiorpyriphos (Durshan) 20 EC	2.5
Endosulfan (Thiodan) 35 EC	1.5
DDVP (Dichlorvos) 76 EC	0.7
EC= Emulsifiable Concentrates

e) PULSE BEETLE

Scientific name: Callosbruchus chinesis Linn.

Preferred Common Name- Chinese bruchid

Class : Insecta

Order: - Coleoptera

Family: -Bruchidae
Genus: Bruchus or Callosbruchus (= Pachymerus)

Species: chinensis (Linn.)

International Common Names

English: adzuki bean weevil, oriental cowpea bruchid, southern cowpea weevil

Callosobruchus chinensis is major pest of pulses in Asia and other regions. It is a holometabolic insect with the egg and adult stage found on the grain and the larval and pupal stages living inside the grain.

Distribution: The two most widespread species of bruchid beetle are C. maculatus and C. chinensis, which are distributed throughout the tropics and sub-tropics. C. chinensis originated in tropical Asia where it is still the dominant species.

Marks of identification

i. Adult beetles are 3-4 mm in length, oval in shape, chocolate/reddish brown in colour, and have long, erected antennae.

ii. The adult beetle is more or less tapering at the anterior end.

iii. There are two ivory coloured spots in the middle of the dorsal side of its body.

iv. The grub is white, cylindrical, and fleshy and wrinkled with brownish month-parts. It is always found inside the grain.

Fig.2.2.20. Pulse Beetle Adult – Bruchus chinensis

· Host plants

C. chinensis is a major pest of chickpeas (Pandey and Singh, 1997), lentils, green gram, broad beans, soybean (Srinivasacharyulu and Yadav, 1997; Yongxue et al., 1998a) adzuki bean and cowpeas in various tropical regions. It also attacks other pulses on occasions, but appears to be incapable of developing on common beans (Phaseolus vulgaris).

· Life history

i. Adult beetle is 3-4 mm long, female being larger, brownish in colour, broader at shoulders and rounded posteriorly. There are dark patches on elytra and thorax.

ii. Adults show sexual dimorphism. Males possess deeply emarginated or indented eyes and prominently serrate antennae, while in female these characters are not distinctly marked. In females tip of abdomen is exposed while in males it is covered by elytra.

iii. The female lays between 1-8 oval shaped and scale-like eggs/grain. The eggs are deposited mostly singly but sometimes in-groups on the surface of seeds and pods. In the fields, eggs are even laid on green pods, which carry infestation to the store. A female can lay from 60 to 95 eggs. Fecundity is about 100 eggs per female. Eggs are whitish, elongated and stuck on the grains or on pods and sometimes on the surface of the container. Egg stage lasts for 4-5 days.

iv. On hatching, larva enters the grain and becomes full-grown in 2 to 3 weeks. Each larva completes the life cycle in a separate chamber. Grubs are scarabeiform or eruciform, plump and with short legs and yellowish in colour. First instars larvae bear functional legs and a pair of thoracic plates to facilitate boring into the seeds. They feed on the inner contents of the grain and may damage several grains during development. Larval period may vary between 12 and 20 days.

v. Pupation takes place inside the grain and pupa is dark brown in colour. Occasionally pupation may take place outside the grain in a cocoon made of excretory matter.

vi. After 4 to 8 days the adults come out of the grain. It can fly and spread the infestation from store to the field. Adults live for 10 days or more. Completion of life cycle takes 4-5 weeks and there may be 6-7 overlapping generations in a year.

In India the insect breeds freely from March to November and hibernates in the larval stage during the winter. The adult emergence takes place from January to April.

Fig.2.2.21. Schematic Life cycle of Pulse beetle

· Nature of damage

It is a major pest of pulses in store. However, field infestation is also common. As the larva eats up the endosperm it is the most damaging stage of the life cycle. The young grubs burrow into the pod or grain and continue to develop inside the grain. The holes seen on pulses are the exit holes from where the adults have emerged. Such grains are unsuitable for sowing. The pest causes maximum damages during February to August, when all its developmental stages exist simultaneously. Cowpea varieties with resistance to this pest are under development (e.g. Soma et al., 2008).

· Control measures

Prevention and Control

Chemical Control

It is difficult to control the pest in the field. In storage however fumigation with carbon-di-sulphide at the rate of 1 lb/100 cu.ft. Or 2.5 1b EDCT/100 cu. ft. or methyl bromide at 1 lb/1000cu.ft. would control the pest.

Callosobruchus spp. may be controlled by fumigation treatment with phosphine, although legislation in many regions now frequently prohibits or restricts the use of these products. Sealed or hermetic storage affords some protection against C. chinensis (Singh and Yadav, 1996; Shaw, 1998).
Approved grain insecticides, especially organophosphates, will protect against infestation.

When grain pulses are stored at farm level the admixture of vegetable oil or essential oils can give protection. Many of these products have been traditionally used by subsistence farmers, thereby reducing the need for, and risks associated with, the use of insecticides. The mode of action of these biological may be insecticidal or anti-ovipositional.

The list of plants and plant extracts shown to have insecticidal or anti-ovipositional effect against C. chinensis and other bruchid pests is very long, including for example: Acacia nilotica, Crinum defixum, Achyranthus aspera, Lantana camara, Acorus calamus . Alpinia galangal, Amoora rohituk,a Cassia occidentalis, Cedrus deodara, Chamomilla recutita, Cymbopogon citratus.

The most well known of anti-bruchid phytochemicals is azadirachtin which has been used alone, in 'botanical insecticides' or as a component of leaves or extracts (liquid or powder) of the neem tree, Azadirachta indica, particularly in the Indian subcontinent (Kumari and Singh, 1998; Ahmed et al., 1999). Azadirachtin is both an anti-ovipositant and insecticide (larvicide and adulticide). Neem oil and other extracts or neem derivatives may be applied directly to seeds, where volatiles also have a fumigant effect.

Cultural Control and Sanitary Methods

Intercropping maize with cowpeas, and not harvesting crops late significantly reduced infestation by C. chinensis).

Good store hygiene plays an important role in limiting infestation by these species. The removal of infested residues from last season's harvest is essential, as is general hygiene.

Solarization (or drying and heating) can be used to control infestations of C. chinensis without affecting seed germination.

Irradiation
Irradiation by ionizing gamma radiation has the potential for being used for disinfestations in stores, although the practice is not widely allowed and may be costly (Bui-Cong-Hien et al., 1997).

Economic importance

Though it is an important pest of pulses in storage, minor incidence is noticed in the field on pods from which the infestation is brought to the storage.

f. RICE WEEVIL/BLACK WEEVIL (Sitophilus oryzae Linn.)

There are three types of rice weevil

1. Rice or black weevil

2. Maize weevil

3. Granary weevil

Scientific name: Sitophilus oryzae Linn.

Common name: Rice weevil, Vernacular name- Sonde

Class: Insecta

Order: Coleoptera

Family: Curculionidae

Genus: Sitophilus

Species: oryzae

Distribution: All over India and many other countries though not worldwide.

Marks of Identification

The insect can be identified easily by the following criteria:

· Size is around 3 mm

· It possesses characteristic long slender beak or snout

· Antennae are elbowed and slightly clubbed

· Hind wings are present except in granary weevil

· The color ranges from reddish brown, chocolate to almost black

· The maize weevil is the largest amongst the three species.

· It has slender, hard-shelled bodies that appear pitted or scarred with tiny holes.

· Rice weevils have four faint red-brown spots on the back of the abdomen.

· They are able to fly and have small round pits on the surface of the thorax.

Host plants: Rice weevil mainly affects stored food grains such as wheat, rice, maize and sorghum.

Life history

The egg, larva, and pupa stages of these weevils occur in the grain kernels and are rarely seen. Feeding is done within the grain kernel, and adults cut exit holes to emerge. Emergence holes of Females drill a tiny hole in the grain kernel, deposit an egg in the cavity, then plug the hole with a gelatinous secretion. Females start laying eggs 5 days after emergence. The eggs are minute, white, translucent 0.7x0.3 mm in size. Female rice weevils lay between 300 to 400 eggs. From eggs after completion of incubation period of 5-8 days depending on temperature the egg hatches into a young larva or grub which bores toward the center of the kernel, feeds, grows, and pupates there. The larva shows four instars. The larval period lasts for 25-35 days. The grub is apodous i.e. without legs. The full grown larva pupates inside the grain. The pupa is curved and takes 3-6 days to emerge as an adult. New adults bore emergence holes from the inside, then leave to mate and begin a new generation. The adults live 3 to 6 months, infesting grain in the field. Two larvae can develop in one wheat kernel. The life cycle of the insect is completed in about 26 days at 30°C and 75% relative humidity (RH). The optimum climatic conditions particularly the temperature for development, ranges from 26°C to 30°C.

Fig.2.2.22. Schematic Life cycle of Rice weevil

Fig. 2.2.25. Life Stages of Rice weevil Sitophylus oryzae.

Nature of Damage

The damage to the grains is mainly caused by two stages of this insect

(1) Larvae

(2) Adults

Due to infestation by the above stages of the insect, the grains are hollowed out and in some cases the kernels are reduced to mere powder. Rice weevil and maize weevil are also known to cause infestation right from the field. Adult insects cut circular holes in the grains. When the intensity of infestation increases it results in heating, referred to as dry heating. Grains with less than 10% moisture are not attacked by the insect.

Control measures

Cultural Practices

The simplest and most effective measure is to locate the source of infestation and quickly get rid of it. If practical and regulations allow, dispose of heavily infested foods in wrapped, heavy plastic bags or in sealed containers for garbage removal, or bury deep in the soil. If you detect an infestation early, disposal alone may solve the problem. Properly ventilate the storage area to discourage these moisture-loving stored product pests. Be sure to store only clean, dry grain with a moisture content of 12 percent or less to reduce weevil problems.

Chemical Control

Grain insects are declared under the Agriculture and Related Resources Protection Act. Limited chemical controls are available to farmers and emphasis is placed on clean hygienic storage and cleaning of machinery. Farmers are encouraged to purchase and maintain sealed farm silos to increase the effectiveness of fumigation.

Economic importance

Rice and granary weevils are harmless to people, houses, furniture, clothing and pets. They cannot bite or sting and they do not carry diseases. They will not feed on furniture, the house structure or other items. The harm they do is destruction of the seeds they infest. About 70% stored grains are lost every year due to insect damage in India. The annual loss caused by stored grain pests to our stored and packaged food run into several hundred corers of rupees.

Questions:

1. Give an account of life-cycle and control of Jowar stem borer.

2. Give an account of nature of damage and control measures of Jowar stem borer.

3. Describe the life cycle, identification marks, damage and control of Brinjal fruit borer.

4. Describe the life cycle, identification marks, nature of damage and control measures of Mango stem borer.

5. Describe the life history of Rice weevil.

6. Describe the nature of damage and marks of Identification of rice weevil.

7. Give the control measures of Rice weevil.

8. Give the marks of Identification and life history of pulse beetle.

9. Give the nature of damage and control measures of pulse beetle.

10. Give the scientific names of Jowar stem borer, Mango stem borer, Brinjal fruit borer, Rice weevil, Pulse beetle.

11. What is dead hearts? Give its scientific name and control measures.

12. What is fumigation? Give any two fumigants for control of Stored grain pests

*****

2.3 Non Insect Pest

2.4

3.1

(Rats and Bandicoots, Crabs, Snails, Slugs, Birds and Squirrels)

Besides insect pests, other invertebrate and vertebrate animal pests attack the agricultural crops, stored grains, vegetables, fruits and stored products, etc., and cause damage to them. It has been estimated that about 5-10% of damage to agricultural crops and stored products is caused by non-insect pest in India. The important non-insect pests are rats in fields and warehouses, bandicoots, wild animals like Jackals and pigs, birds, crabs, snails etc. cause damage to grains, crops in fields. A brief account of some non-insect pest and their control measure are described below:

1. RATS AND BANDICOOTS:

These are rodents. These belong to order Rodentia, class Mammalia and phylum Chordata. Rodents such as rats, mice, gophers and ground squirrels spread diseases like plague, rat bite fever and leptospiral jaundice in human beings. They damage the standing crops and cause substantial loss during storage of the produce.

About Rat

Order: Rodentia

Suborder: Myomorpha

Super family: Muroidea

Family: Muridae

Subfamily: Murinae

Genus: Rattus

Species: 50 species

Body Length: 9 to11 inches

Tail Length: 7–9 inches

Weight: 350 to 450 grams (female)/ 450 to 650 grams (male)

Life Span: 2 to 3 years

Diet: Rat is omnivores. The things it consumes include seeds, fruit, grains, nuts, flowers, leaves, insects, birds, reptiles, fish, eggs and fungus.

Range: Originated in Asia and found throughout the world.

Habitat: In any situation that provides food, water and shelter

Age of Sexual Maturity: 5 weeks

Gestation Period: 20 to 22 days

Number of Offspring: 8 to 12 babies in a litter but can have as few as 1 and as many as 20.

They are prolific breeders. Their breeding period starts at the age of 3-4 moths and continue through the year and a single female produces five litters in a year, each litter usually consists of nine to ten young ones. Thus, a pair of rat may give rise to about 100-150 young ones in a year. In coastal areas of Maharashtra, the coconut is reported to be damaged by rats. In India, it is estimated that the rat populations about 2400 million. In India the common species of rats recorded are, house rat or Black rat- Rattus rattus, the house mouse - Mus musculus and Common Indian field mouse- Mus musculus booduga, Brown rat or Norwey rat - Rattus norvegicus. The black rats are expert climbers and prefer to live in the roofs of buildings.

They remain in the crowns of the coconut. Palm feeding on the nuts of all stages. They not only damage the grains and crop plants but also act as carries for some germs (leading to produce diseases (i.e. plague, etc.) Rattus rattus is the common species of rat, nocturnal in habit.

Rat-burrows damage the irrigation canals also. Rats cause heavy damage to stored grains in godowns. It has been estimated that a single rat consumes about 9 kg of food grains per year. The groundnut crop is attacked by rats during harvest. It has been found that rats spoil (due to contamination of excreta) about ten times more than it consumes.

These vertebrate rodents cause damage to agricultural crops plants like rice, wheat, jowar, sugarcane, etc. by cutting down the plants and feeding on them.

In several tropical countries rodents (rats and mice) cause much more loss and damage to food grain than insect pests.

Bandicota bengalensis

Fig. 2.3.1. Common species of rodents in storage and field.

Bandicoot rat, of five Asiatic species of rodents closely associated with human populations. The greater bandicoot rat (Bandicota indica) is the largest, weighing 0.5 to 1 kg (1.1 to 2.2 pounds). The shaggy, blackish brown body is 19 to 33 cm (7.5 to 13 inches) long, not including a scantily haired tail of about the same length. Greater bandicoot rats are found on the Indian subcontinent and throughout Indochina; additional populations on the Malay Peninsula, Taiwan, and Java probably represent inadvertent or intentional human introductions.

The lesser bandicoot rat or Indian mole-rat (Bandicota bengalensis) is a giant rat of Southern Asia, not related to the true bandicoots. They can be up to 40 cm long (including the tail), are considered a pest in the cereal crops and gardens of India and emit pig like grunts when attacking. The name bandicoot is derived from the Telugu language word pandikokku, which translates loosely to "pig-rat". Like the better known rats in the genus Rattus, bandicoot rats are members of the family Muridae. Bandicoots have elongated, pointed muzzle used for rooting the soil. Their fur is dark or (rarely) pale brown dorsally, occasionally blackish, and light to dark grey ventrally. The head-body length is around 250 mm, and the uniformly dark tail is shorter than the head-body length. These species are terrestrial, nocturnal or active at twilight, constructing burrows where they nest and where they bear their litters, which number from 2 to 18. They subsist on grains, fruit, and invertebrates and are destructive to cultivated crops. The lesser bandicoot rat, an especially aggressive burrower, has been reported to make tunnels in the concrete cellars of rice warehouses in Calcutta. They are pests of grains in field and store grains in houses and godowns and root crops as like rat.

Habits and characteristics of rodents:

- They can climb or jump until 60 and 90 cm

· They can swim across pools of water

· They dig and barrow holes through soil, hard structures, containers and objects

· Usually they do same activities every day

· The follows same path over and over

· They are away of new things as for example new baits

Rodent’s loss and damage to food grain:

· They eat and destroy the grain

· They foul and contaminate grain and cooked food with their feces, urine and hairs

· They damage crop in field and storage

· They can destroy buildings, structures, containers and personal clothing and bedding

· They spillage stacked bagged foods, storage structures and food containers

· They can attack young chicks and may attempt to feed on human feet, causing sores and walking difficulties to their victims

· They may cause disease to man and animals

Fig.2.3.2. Rat feeding on human food.

Control Measures:

· By using various types of rodents traps

· By using domesticated cats

· By hunting rodents in the probably hiding places.

The rodents (rats and bandicoot) can be killed by anyone or combined method described below:

A. Rat Traps: In this method the rats are trapped by various mechanical devices which are used in modified form in different locality to control the rats. This method takes much time and man power. So practically, it is very difficult to apply in larger field areas. This method is also practiced in houses to catch rats. With the help of traps containing attractive food near their burrows, rats can be trapped. If one of the fellow is caught in the trap, due to the strong instinct of self- preservation others keep away from the trap. To kill any trapped rats, place the whole trap in a sealed container (like a bucket with a lid and filled with carbon dioxide).So sometimes trapping method may not be very effective.

B. Hunting: It is practiced by group of persons accompanied by trained cats and dogs. Men dig out the rat and bandicoot holes and when the animals come out of the holes, cats or dogs kill them. At times the burrows are flooded with the water to force the rats and bandicoots out and they can be killed mechanically.

Chemical control (Poisonings): Rodenticides

Compounds, which kill the rodents by their chemical action, are known as rodenticides.

The following chemical preparations are most commonly used and are very effective on rats and bandicoots as poison baits.

i. Zinc phosphide (Zn₃P₂): A greyish black powder with strongly disagreeable odour. When zinc phosphide is ingested, it reacts with stomach acids and causes poisonous phosphine gas to be released. This leads to nausea, vomiting, pulmonary oedema, and eventual death. Zinc phosphide, acute stomach poison is used as a bait at 2% strength, mixed with popcorn, rice, dry fish, onions etc., Pre baiting is essential as rats exhibit bait shyness to this. In paddy fields, two rounds of baiting before and after sowing nursery and another two rounds in planted crop are required. About 500 g of poison is needed per hectare.

Formulation: 80% powder

Trade name: Zintox

LD50: 46 mg/kg

It releases Phosphine (PH3) gas when it comes in contact with moisture. It is very common poison used to kill the rats and bandicoots. For preparation of poison bait 500 gms of wheat or bajara or sorghum flour moistened with water and is then mixed with 30 gms of poison. We can also add 25 gm of Jaggary, 10-15 ml of cotton seed or groundnut oil and about 150-200 baits or pills of equal size can be prepared. Two pills are kept near the mouth of the burrow in the evening. For bandicoots baits of little larger size are used. On next day in the morning bait must be checked and unused baits must be properly disposed to avoid contact with children or pet animals and birds.

ii. White arsenic: It is one of the arsenical compounds. It is useful for field rats and bandicoots. The poison bait preparation involved following composition.

White arsenic - 12gm

Cooked jowar flour - 1,000 gm

Groundnut kenel - 250 gm

Water - Sufficient to make a thick paste.

Prepare small pills/cakes of equal size and keep 2 or 3 pills in each burrow and then close the burrow.

iii. Strychnine Sulphate: For the preparation, dissolve 30 gms of strychnine sulphate in 60 ml of warm water. Heat 2 kg of jaggery in 500 ml of water to prepare thick syrup. Then mix both the solutions thoroughly and add to this 14 kg gram previously soaked for 12 hours in water and make the approximately 15 grams bolls. Put 15 grams of poison bait boll in each rat burrow and then it is to be closed with mud. This chemical is highly toxic to human beings hence should be used only when other poisons have failed.

iv. α-Naphthylthiourea (ANTU) is an organosulfur compound with the formula C₁₀H₇NHC(S) NH2. This white, crystalline powder although commercial samples may be off-white. It is used as a rodenticide and as such is fairly toxic. Naphthylthiourea is available as 10% active baits in suitable protein- or carbohydrate-rich materials and as a 20% tracking powder.

v. Barium carbonate: It is white amorphous poison used for killing of rats. About 500 gms of Barium carbonate is mixed with 2.0 – 2.5 kg of sufficiently moistened bajara or wheat flour to prepare the rat baits. It is a weak poison, till it is satisfactory for use in houses.

vi. Kuhia seeds (strychnous nux vomica): Boil about 150 gms of the seeds in 2 litres of water so often seeds then crushed and continue boiling to get 100 gm of the extract remains. Heat 2 kg of jaggery in 500 ml of water to prepare thick syrup. Then mix both the solutions thoroughly and add to this 14 kg previously soaked for 12 hours in water and make the approximately 15 grams bolls. Put 15 grams of poison bait boll in each rat burrow and then it is to be closed with mud.

vii. Anti-Coagulant Rodenticides: Anticoagulants are defined as chronic single-dose or multiple-dose rodenticides, acting by effectively blocking of the vitamin K cycle, resulting in inability to produce essential blood-clotting factors

Bromodiolone (2^nd generation anticoagulant): It acts by depressing the hepatic vitamin K dependent synthesis of substances essential to blood clotting. It is a single dose anticoagulant rodenticide from Coumarin group. The technical material (97% pure) is an odourless, yellow-white powder. Bromadiolone is vitamin K antagonist. The main site of its action is the liver, where several of the blood coagulation precursors under vitamin K dependent post translation processing take place before they are converted into the respective procoagulant zymogens. The point of action appears to be the inhibition of K1 epoxide reductase.

Formulation: Solids

Trade names: Roban, Moosh- Moosh, Bromard; Bromatrol; Bromone^R; Bromorat

Deadline; Hurex

LD50: 1-3 mg/kg

Moosh-Moosh: This is also readily available bait in the market in cake form. It is widely used to control rats from rice, sugarcane coconut and soya bean fields. One or two cakes are placed in each rat hole at 5-10 meter, intervals along bunds in fields. For coconut and oil palm place two cakes on the crown (top) and at the base of each bunch of fruits. This rodenticide kills 5-100% rats with a single feeding. Application of Moosh Moosh is most economical and effective. Ratoon, Mortem rat kill etc. are readily available in the market in cake form. These are equally effective as moosh-moosh for the control of rats and bandicoots.

Warfarin (1^st generation anticoagulant): It is a well known rodenticide available in market. Its action is slow and causes internal haemorrhage. 0.5% warfarin baits are readily available in the market. The composition constitutes 1 part of warfarin ± 19 parts of food (bran) and vegetable oil. Baits must be eaten by rats for 4-5 days continuously to cause the death effect. Rats are more suspicious to new baits so initially non- poisonous prebaiting for 2-3 days may be practiced to train the rats to come to regular feeding points and on third or fourth day evening poison baits may be kept. The poison fed rat suffers by weakness due to loss of blood and death may occur after 3 to 15 days of poisoning (Prakash, 1976). On the next morning the dead rats must be immediately removed with uneaten baits. Unused baits must be properly disposed to avoid contact with children or pet animals and birds. Warfarin is highly toxic to other animals hence one should take care while handling.

Warfarin, Fumarin, Toumarin, Recumin

These poisons are lethal when consumed for several days. They prevent blood clotting and break cell wall of blood capillaries leading to haemorrhage. Rats normally die in aerated areas. House rat and house mouse die after 2-5 days of continuous feeding.

Solid base – Rodafarin C

1 part of Rodafarin C + 1 part of granulated sugar + 1 part of vegetable oil + 17 parts of crushed grain or corn meal

Liquid base –Rodafarin C

Antidote- Vitamin k-1

Fumigation: It involves treating of rat burrows with the fumes of poisonous substances called as Cyanogas A dust or Celphos tablets. It contains 3 gms of Aluminium Phosphide. It is an inorganic phosphide used to control insects and rodents in a variety of settings. It is mainly used as an indoor fumigant at crop transport, storage or processing facilities for both food and non-food crops It may also be used as an outdoor fumigant for burrowing rodent control, or in baits for rodent control in crops. Aluminium Phosphide is available in pellet and tablet form. Under optimum moisture conditions, it liberates ‘Phosphine’ gas, which is highly toxic. ¼ to ½ of a 3 g tablet is put in a live burrow; a little water is added if necessary and the burrow closed with mud. Repeat the operation if the burrow remains closed. Also used to fumigate the godowns @ 1tab/ ton / 5 days and also@ 1 or ½ tab/tree against red palm weevil.

Formulation: Tablets (3g)

Trade name: Celphos, Fumitoxin, Phostoxin, and Quic k Phos.

LD50: 11.5 mg/kg

The Cyanogas A’ dust is a powder, which when comes in contact with the atmospheric moisture liberates HCN gas. It is highly toxic to rats, bandicoots and other animals.

Mode of Application:

Apply the powder dust of Cyanogas ‘A by cyanogas foot pump (fumigator) into burrows where rats inhabit and then close the mouth of burrow by wet mud. About 200 gms of calcium cyanide A’ is sufficient to treat about 100 burrows. Celphos tablets - 2-3 tablets are put in each burrow, and then close it with mud. Both can be used in warehouses and godowns in the same procedure like field treatment.

The following precautions must be taken during construction of warehouses and godowns.

(a) Ventilators, windows, rain water drains, pipes, etc. should be made rat proof by covering them with a wire mesh with less than 5 mm pore size.

(b) Flooring of the warehouses and godowns should be without of cracks and gaps; if such are there it should be properly closed.

(c) There should not be gap between the lower edge of the doors and floor to avoid entry of small rats. The bottom of the doors must be covered with metal cuffs or plastic cuffs.

x. Ultrasonic devices: Ultrasonic methods can be used only in godowns and warehouses with facilities of electricity. It has been recommended by Hanery Simon (1967) that ultrasonic waves are very much powerful killers to rats without any damage to human beings. Ultrasonic equipments are now available in market which can produce sounds inaudible to human ears but such sounds which will cause pain and irritation to the ears of rats.

Rats exposed to such sounds may eventually die. Such equipments may be used for rat control both indoors and outdoors. By using this device it has been claimed by the manufacturer that rats can be eliminated within 72 hours.

xi. Electrocuting : In many advanced countries, iron fences carrying electric currents are placed around the fields infested with rats so that rat when move across and come in contact with the electrically charged fences get killed. This method is very useful and human tolerable electric fencing may be applied for the fields in India.

2. CRABS (Parateiphusa spp.):

These are locally referred as Khekada, Chimburi and Muthya. Crabs are polyphagous. The rice field crab Paratelphusa hydrodromus (Decapoda; Crustacea). They are nocturnal and are active during night time. The crab has an oval body with an abdomen tucked beneath the thoracic region. Crabs live in holes made in the sides of field bunds, irrigation channels and field corners, where water does not stand. The holes are protected by heaping soil around their openings. Crabs multiply mainly during dry period, April to June. A single female lays about 200 eggs which are carried by the mother in a pouch like abdominal flap on her ventral side. These are reported to cause heavy damage to paddy crop in Ratnagiri (Konkan), Thana and Kolaba districts of Maharashtra State.

Fig. 2.3.3. Rice field crab

Three species in India cause damage to crop. These damage young seedlings in nurseries and newly transplanted fields. The seedlings are cut near the ground level in to small bits. These bits then are carried to their burrows for feeding. In older plants, outer sheaths are cut open and the tender inner portions are consumed. In an attacked field, bits of leaves and stems can be seen floating in water. In severely affected fields patches of damage can be seen. Crabs are active mostly after dusk and at nights. In addition to damage to plants, the crab holes made in bunds lead to braches and water losses.

Control Measures:

1. Crab burrows fumigation with Cyano gas though effective is costly.

2. They are naturally controlled by rats and pond heron Ardeloa grayi.

3. They can be trapped in wide-mouthed pots buried with their rim at about the water level; inside the pots, moistened rice bran in lumps are kept as bait.

4. Poison baiting with warfarin 0.0025 per cent in popped rice mixed with fried onions and fish can be used.

5. Poison baiting of 5% DDT, ± 1% dieldrin or 0.08% endrin with rice syrup or .0.5% endrin or parathion at the rate of 80-100 ml per burrow can also be used to control the crabs.

4. SNAILS AND SLUGS:

These are non-insect invertebrate pests and are herbivorous in habit. The giant African snail – Achatina fulica, which is a foreign pest got introduced in India and is now wide spread.

Slugs and snails are legless creatures that glide along on a path of mucus. This mucus dries out and can be seen in the daytime as a shiny trail over leaves, fruit and soil. The detection of these "slime trails" may be the only way of determining their presence, as slugs and snails generally feed at night.

WHAT IS A SNAIL AND WHAT IS A SLUG?

Snail is a common name that is used for almost all members of the molluscan class Gastropoda which have coiled shells in the adult stage. Those snails which do not have a shell or only a very small shell are usually called slugs.

Snails are soft-bodied molluscs, with a hard shell; they can eat holes in leaves, stems and flowers of many plants.

The snail most commonly encountered in gardens is the common garden snail, Cornu aspersa. Banded snails, Cepaea species, which are a little smaller and often brightly banded yellow, white and brown, may also be numerous, but these are much less damaging to plants. The giant African snail – Achatina fulica, which is a foreign pest got introduced in India and is now wide spread. Slugs and snails are legless creatures that glide along on a path of mucus. This mucus dries out and can be seen in the daytime as a shiny trail over leaves, fruit and soil. The detection of these "slime trails" may be the only way of determining their presence, as slugs and snails generally feed at night.

Snails are most active after dark or in wet weather, and the tell-tale slime trails, if present, can alert you to the level of activity. Snails and slugs cause similar damage and can climb, often to a considerable height, above ground level. Because of the protection provided by their shells, snails can move more freely over dry terrain than slugs. Snails are less common than slugs where acid soils prevail and, unlike slugs, they remain dormant over winter, often clustering together under empty upturned flower pots, stones or other protected places.

Reproduction occurs mainly in autumn and spring, when clusters of spherical, yellowish-white eggs can be found under logs, stones and pots.

Snails eat a wide range of vegetables and ornamental plants, especially seedlings and other soft growth; they are good climbers and can be found high up in some plants. Most damage is done in spring by snails feeding on seedlings, new shoots and plant crowns. Snails will also eat decomposing organic matter such as rotting leaves, dung and even other dead slugs and snails.

Fig. 2.3.4. Snail Fig.2.3.5 Banana slug

Symptoms of snails’ presence:

You may see the following symptoms:

Snails sometimes leave behind slime trails, which can be seen as a silvery deposit on leaves, stems, soil and hard surfaces
Snails make irregular holes in plant tissues with their rasping mouthparts. Young shoots and leaves are damaged or eaten, not only at ground level but often high up

WHY TO CONTROL SNAILS AND SLUGS?

In the wild, snails and slugs eat a variety of different foods. They can cause damage to agricultural crops and garden plants, and are therefore often regarded as pests. Aquatic snails eat other varieties of food such as plankton, algae, plants, and other microscopic organisms that live underwater.

The land snails and slugs damage gardens, orchards, green houses and mushroom beds as they feed on succulent parts of seedlings and mature plants. Pila spp. suppose to damage paddy fields, Helix spp. feed on living vegetable matter like leaves and fruits during night, and African snail Achatinafulica is serious pest of fruits, vegetables and ornamental plants in coastal areas of Orissa, W.B., Assam, Tamil Nadu and Kerala. These pests do most of their damage at night and on wet, cloudy days. They are most active throughout the spring, early summer and again after autumn rains begin. In warm and wet climates slugs and snails can be active all year. During the day they hide in dark, moist sites under decaying leaves, low growing plants, dirt clods, pots or debris. Slugs are also quite capable of burrowing into the soil by following decayed plant roots, cracks, worm tunnels and along boards surrounding raised beds. These pests are also excellent climbers and can be seen quite high in plants. Snails in particular can seriously damage citrus trees. Snails can cause damage to crops, particularly at the early stages and thus be agricultural pests. Besides this it may be vectors of diseases such as Schistosomiasis from veterinary and medical point of view.

What Does Slug Damage Look Like?

Large, ragged holes in tender leaves and flowers.
Damage during the spring before many insects is active.
Traces of silvery slime on chewed leaves or along the ground.
Seedling leaves completely gone with only a small stem remaining.
Holes in hostas, lettuce, asparagus, the flowers of spring bulbs and many other plants.
Tiny scalloped edges. Large slugs can quickly devour a leaf by taking row after row of small bites.

Fig.2.3.6. Heavy slug damage on broccoli leaves

Control

Snails are so abundant in gardens that some damage has to be tolerated. They cannot be eradicated so target control measures on protecting the more vulnerable plants, seedlings, vegetables and soft young shoots on herbaceous plants.

Non-chemical control

There are various measures you can take:

Transplant sturdy plantlets grown on in pots, rather than young vulnerable seedlings. Transplants can be given some additional protection with cloches
Encourage predators such as thrushes, toads, hedgehogs and ground beetles. The nematode (‘Nemaslug’), Phasmarhabditis hermaphrodita, used to control slugs in the soil is unlikely to control snails, since they spend most of their time at or above soil level
Place traps, such as scooped-out half orange, grapefruit or melon skins, laid cut side down near vulnerable plants, or jars part-filled with beer and sunk into the soil. Check these and empty them regularly, preferably every morning. Proprietary traps and barriers are also available from garden centres
Barriers made of crushed rocks (e.g. Westland Earth Matters Slug Blocker Granules, Growing Success Slug Stop, Vitax Slug Off) can be placed round vulnerable plants, as can repellent gels (e.g. Doff Slug Defence Gel, Westland Earth Matters Slug Blocker Gel). Copper tape (e.g. Vitax Copper Slug Tape, Agralan Copper Slug Tape, Growing Success Slug Barrier Tape) can be put round pots, or the pots can be stood on copper-impregnated mats (e.g. Slug and Snail Shocka, Agralan Slug and Weed Mat)
Go out with a torch on mild evenings, especially when the weather is damp, and hand-pick snails into a container. Then, either take them to a field, hedgerow or patch of waste ground well away from gardens, or destroy them in hot water or a strong salt solution
In winter turn over likely hiding places to expose snails for thrushes to feed on.
If weeds invade the exposed areas a thick layer of mulch unattractive to slugs can be laid as ground cover, materials with rough and jagged edges are preferable, such as broken eggshells.
A barrier of vegetation favoured by slugs, such as wilted comfrey leaves, can be placed around vulnerable vegetation as a decoy.
Use of Predators: Hedgehogs, ducks, chickens, frogs and toads are all predators of snails and slugs. Hedgehogs eat slugs, beetles, caterpillars etc. and are an excellent addition to pest control strategies in the garden.
Ducks and chickens also supplement their diet with slugs but care needs to be taken to decide which breed to purchase and how they will be housed. Chickens can cause damage to valuable plants and it is a good idea to move them around in pens or let them into the garden at the end of the day when they may be looking for an alternative to plant food. Ducks like to be near to water containers but do not necessarily need a pond, they can be moved around in pens on a rotation basis if they are trampling areas of vegetation.
Rove Beetles (Ocypus olens) are natural predators of slugs and snails.

· Go hunting. Slugs and snails tend to congregate in dark, damp, cool spots like the edge of lawns, under logs or mulch, and around the sides of raised beds. Look for them in early morning. Drown any you find in a jar of soapy water and then toss them on your compost pile. Try crumpling up a piece of newspaper and placing it into the garden at night. Slugs often hide out in the paper and you can just pick it up and toss it in the trash in the morning. I also avoid mulching in my vegetable garden until the weather warms up and the soil surface stays pretty dry.

· Feed them to the birds. If you have chickens, let them loose into the garden before planting in spring to gobble up slugs and weeds. During the garden season I hunt for slugs and snails and toss them into the chicken run as a snack for our hens.

· Attract ground beetles. Slug eggs are a ground beetle's favorite meal. Lure these good bugs to your garden by planting low, perennial plants that provide shelter, such as ornamental grasses, oregano, and thyme.

· Make beer traps. Slugs and snails are drawn to the yeasty smell of beer like college kids are to a keg. To make a beer trap, simply bury a shallow container, such as a yogurt or keg cup, in the garden. Leave the rim of the container one inch above the soil line to prevent ground beetles from accidentally falling in. The slugs will smell the beer, crawl right into the container and drown. Simply dump the contents onto your compost each morning and refill the cup. I've found the cheaper the beer, the better it works. In fact, we once used up an entire batch of bad home brew in slug traps. It tasted terrible to us, but the slugs didn't seem to mind.

Chemical Control: Molluscicides

WHAT ARE THE CURRENT METHODS OF CONTROL?

The range of pesticides used to kill slugs and snails are called molluscicides. The slimy creatures are easy to control with organic slug baits. These products contain iron phosphate, which causes the slugs and snails to lose their appetite when they ingest it. Eventually they die of starvation (not poisoning). Molluscicides may also contain a desiccant preventing molluscs from producing the mucous essential for survival.

Metaldehyde is one Chemical used. Generally it is presented in a bright colour, making them attractive to children and pets, especially dogs. Metaldehyde works by disrupting the gastric organs. Poison baits: Use of poison bait with metaldehyde, a polymer of acetaldehyde is the best known chemical control of snails. It is applied as bait mixed with bran and the dosage is very low. About 400 gm of metaldehyde mixed with 30 kg of bran is sufficient per hectare will control slugs. It is toxic to snails by contact as well as ingestion. The chemical immobilizes snails and copious slime is exuded out of the body of snails and they die of dehydration. Metaldehyrde have low mammalian toxicity.
There are two types of pellet available to the gardener; those that contain metaldehyde (e.g. Slug Clear Ultra Pellets, Bayer Bio Slug and Snail Killer, Doff Slug Killer Blue Mini Pellets, Westland Eraza Slug and Snail Killer) or ferric sulphate (e.g. Growing Success Advanced Slug Killer, Bayer Natria Slug and Snail Control, Bayer Organic Slug Bait, Vitax Slug Rid, Doff Super Slug Killer, Sluggo Slug & Snail Killer). Ferric sulphate is relatively non-toxic to vertebrate animals.
Copper sulphate and N-trityl morpnoline (frescon) have been found very useful against snails when they are spread on meadows harbouring these animals.
DNOC or dinitro-O-cyclo-hexyphenol reported to be very effective against snails when

used as herbicide.

The active ingredients Methiocarb and Thiodicarb disrupt the production of cholinesterase, an essential nervous system enzyme.

vi. Aluminium Sulphate is a granular inorganic salt used as a molluscicide and is the least toxic of the chemical controls available.

Use of Repellents:

WHAT DOES REPELS CONTAIN?

Herbs containing Potassium Salts, Activated Carbon, Copper, Alkalies, Herbal Sulfur and also Herbs which are known to expel Snails.

HOW SAFE IS REPELS?

All the ingredients used are GRAS. These have a little pungent smell, hence while handling Gloves, mask and Goggles are to be used.

WHAT IS THE RECOMMENDED DOSAGE OF REPELS?

2 Kg/ Acre on Boundaries with a width of about 6 to 9” to be broadcasted evenly with wet sand about 8 Kg., or dusted entire area after diluting in about 20 kg Calcium Carbonate / 2 Kg.

Hazards of Mollusicides: ARE MOLLUSCICIDES USED NOW SAFE ENOUGH?

Molluscicides not only poison slugs and snails but can also harm domestic animals and wildlife, including hedgehogs and birds, which are natural mollusc predators. There have been incidents of pet animal poisonings resulting in the affected animals dying in agonizing convulsions.

4. BIRDS:

Many species of birds feed upon grains from earheads of field crops; fruits and vegetables. They actually consume very little quantity but often cause more damage than what they actually eat.

Major bird species affecting different crops are as follows

1. Crow Corvus spp. – Damage wheat, cobs of maize, ripe fruits of fig, mulberry

2. The parrot Psittacula cyanocephalus cuts and feeds on maize, jowar, bajra, what, barley grains and fruits such as guava, fig, mango, pomegranate etc., (both semi ripened and ripened fruits are cut and eat leading to fruit drop)

3. The house sparrow – Passer domesticus damages the earheads of jowar, maize, bajra and soft and fleshy fruits such as mulberry and fig

4. The blue rock pigeon Columba livia eats maize, pulses and groundnut

5. The yellow throated sparrow causes heavy damage to wheat and barley.

Some common birds those are in human habitation of them are as follows:

Parrots (Psittacula spp.): There are about eight species of parrots recorded in India. Among these species, large Indian parakeet (P. eupatria) is very common in Maharashtra. It causes heavy damage to orchards by eating fruits and also spoiling the fruits by cutting it with beak. The parakeets are among the most wasteful destructive birds. They gnaw at and cut into bits all sorts of near-ripe fruits such as guava, ber, mango, plums, peaches, etc. In sunflower when the seeds are soft the parrots cause extensive damage by feeding on the seed thus reducing the yield

fig. 2.3.7. Parrot- Indian Ring-necked Parakeet

Psittacula krameri manillensis

(i) Crow (Corvus splendens Vieillot): They are often seen in flocks in maize and other fields. They cause considerable damage to ripe fruits in orchards and also ripening grains of maize and fruits. They may prove a menace to the successful growth of field crops as well as harvest of fruits. They are particularly attracted to the grains when they are exposed on a cob.

Fig. 2.3.8. Crow Corvus Splends

(ii) House Sparrows (Passer domesticus): These cause great damage to various field crops like Jowar, bajara, wheat, maize, etc. mainly in the seed setting stage as they move in flocks. They also threaten mulberry and many other small sized juicy fruits and fruit buds they visit the ripening fruit fields, particularly. Those of wheat in the spring season, and cause much damage both by feeding and causing the grains to shed.

Damage by House sparrows

House sparrows consume grains in fields and in storage. In grain storage facilities, faecal contamination probably results in as much monetary loss as does the actual consumption of grain. They do not move great distances into grain fields, preferring to stay close to the shelter of hedgerows. Localized damage can be considerable since sparrows often feed in large numbers over a small area. Sparrows damage crops by pecking seeds, seedlings, buds, flowers, vegetables, and maturing fruits. They interfere with the production of livestock, particularly poultry, by consuming and contaminating feed. Because they live in such close association with humans, they are a factor in the dissemination of diseases (chlamydiosis, coccidiosis, erysipeloid, Newcastle’s, parathypoid, pullorum, salmonellosis, transmissible gastroenteritis, tuberculosis, various encephalitis viruses, vibriosis, and yersinosis), internal parasites (acariasis, schistosomiasis, taeniasis, toxoplasmosis, and trichomoniasis), and household pests (bed bugs, carpet beetles, clothes moths, fleas, lice, mites, and ticks).

Fig. 2.3.9. House sparrow- Passer domesticus, Male (left) and female (right).

In grain storage facilities, faecal contamination probably results in as much monetary loss as does the actual consumption of grain. House sparrow droppings and feathers create janitorial problems as well as hazardous, unsanitary, and odoriferous situations inside and outside of buildings and sidewalks under roosting areas. Damage can also be caused by the pecking of rigid foam insulation inside buildings. The bulky, flammable nests of house sparrows are a potential fire hazard. The chattering of the flock on a roost is an annoyance to nearby human residents. Nestlings are primarily fed insects, some of which are beneficial and some harmful to humans. Adult house sparrows compete with native, insectivorous birds. Martins and bluebirds, in particular, have been crowded out by sparrows that drive them away and destroy their eggs and young. House sparrows generally compete with native species for favoured nest sites.

Control of Birds:

The damage by birds to crops can be prevented by using scaring devices, reducing their population by shooting, trapping, covering crop with shade nets and use of chemicals.

Preventive measures- Mechanical control

a. Scaring devices using mechanical, acoustic and visual means are normally employed, i.e. beating of drums to produce sounds is still in vogue in many parts of the country particularly in the harvest season.

b. Birds may be scared by display of scare crows, dead birds, visually attractive flags, silver coloured ribbons etc.

c. Trapping the birds in nets or catching them with the help o sticky substance ‘Lassa’.

d. Fire crackers placed at regular intervals along a cotton rope. The rope burns from one end and ignites the crackers at regular interval which produce sounds and scare away the birds.

e. Loud sounds due to the burning of acetylene gas produced at intervals are utilized to scare way birds and small animals.

Chemical control:

a. poison bait - A piece of Chapatti or purries soaked in 0.04% parathion and placed on top of roof or residing places on trees in fields will help to control crows.

b. Repellent-Parrots and sparrows are repelled by spraying 0.6% thiurun’ on wheat crops at milk stage.

For the conservation of bird species, killing methods like trapping, shooting and use of poisonous chemicals as baits has not been practiced in many places, instead birds are scared by many devices.

6. SQUIRREL:

Phylum-Chordata

Class-Mammalia

Order-Rodentia

Family- Sciuridae

Genus-Funambulus

Species- palmarum (Linn.)

Common Name(s): English-Indian Palm Squirrel, Three-striped Palm Squirrel, Common Palm Squirrel,

Distribution-India; Sri Lanka

This is a very adaptable species. It is a diurnal and semi-arboreal. This species occurs in tropical and subtropical dry deciduous forest, mangrove forest, grasslands. Indian Palm Squirrels are also known as the 3 striped squirrel due to the mix of dark and white stripes on the back of the Indian palm squirrel. The Indian palm squirrel can be found nesting in the tree tops of exotic trees.

Identification Marks:

An Indian palm squirrel only weighs around 100g making the squirrel easy prey for small meat-eating mammals and birds. The Indian palm squirrel has often been reported going into people’s houses and often seen running up and down trees and houses.

It is about the size of a large chipmunk, with a bushy tail slightly shorter than its body. The back is a grizzled, gray-brown colour with three conspicuous white stripes which run from head to tail. The two outer stripes run from the forelegs to the hind legs only. It has a creamy-white belly and a tail covered with interspersed, long, black and white hair. The ears are small and triangular. Juvenile squirrels have significantly lighter coloration, which gets progressively darker as they age.

Fig.2.3.10. Indian Palm squirrel

Nature of damage:

While squirrels are a natural part of the environment, they can become pests when they cause damage to residential structures, homes, or plant life.

Squirrels Become Pests:

In Structures: In seeking to build nests, squirrels will chew openings through siding and underneath eaves. They may also through unscreened chimneys and vents, and build nests in these areas as well as in attics. Once in this "nest," squirrels will on continue to chew on insulation of the structure as well as that around wires. These bared wires can then cause a fire.

· To Utilities: Squirrels will run along utility power wires and cables, and can short out the transformers. They gnaw on wires, enter buildings, and build nests in attics. They frequently chew holes through pipelines used in maple syrup production.

· To Other Wildlife: Often squirrels take food at feeders intended for birds. Sometimes they chew to enlarge openings of bird houses and then enter to eat nestling songbirds. Flying squirrels are small enough to enter most bird houses and are especially likely to eat nesting birds.

· To Plant life: Squirrels can damage lawns in digging for nuts; chew the bark and twigs of trees and shrubbery; eat fruits and grains or planted bulbs and seeds; carry off mature nuts; chew holes in maple syrup dispensing tubes.

· In nut orchards, squirrels can severely curtail production by eating nuts prematurely and by carrying off mature nuts. In New England fruit orchards, pine squirrels may eat ovaries of cherry blossoms and destroy ripe pears. Pine, gray, and fox squirrels may chew bark of various orchard trees.

· In gardens, squirrels may eat planted seeds, mature fruits, or grains such as corn.

Typically, they feed on mast (wild tree fruits and nuts) in fall and early winter. Acorns, hickory nuts, walnuts, and orange fruits are favourite fall foods. Nuts are often cached for later use. In late winter and early spring they prefer tree buds. In summer they eat fruits, berries, and succulent plant materials. Fungi, corn, and cultivated fruits are taken when available. During population peaks, when food is scarce, these squirrels may chew bark from a variety of trees.

Damage Prevention and Control Methods

Exclusion

Prevent squirrels from climbing isolated trees and power poles by encircling them with a 2-foot-wide (61-cm) collar of metal 6 feet (1.8 m) off the ground. Attach metal using encircling wires held together with springs to allow for tree growth.

Prevent squirrels from travelling on wires by installing 2-foot (61-cm) sections of lightweight 2- to 3-inch diameter (5.1- to 7.6-cm) plastic pipe. Slit the pipe lengthwise, spread it open, and place it over the wire. The pipe will rotate on the wire and cause travelling squirrels to tumble.

Close openings to attics and other parts of buildings but make sure not to lock squirrels inside. They may cause a great deal of damage in their efforts to chew out. Place traps inside as a precaution after openings are closed. A squirrel excluder can be improvised by mounting an 18-inch (46-cm) section of 4-inch (10-cm) plastic pipe over an opening. The pipe should point down at a 45^o angle. A one-way door can also be used over an opening to let squirrels out and prevent them from returning.

Close openings to buildings with heavy 1/2-inch (1.3-cm) wire mesh or make other suitable repairs.

Custom-designed wire mesh fences topped with electrified wires may effectively keep out squirrels out of gardens or small orchards.

Habitat Modification

Trim limbs and trees to 6 to 8 feet (1.8 to 2.4 m) away from buildings to prevent squirrels from jumping onto roofs.

In backyards where squirrels are causing problems at bird feeders, consider providing an alternative food source. Wire or nail an ear of corn to a tree or wooden fence post away from where the squirrels are causing problems.

In high-value crop situations, it may pay to remove woods or other trees near orchards to block the “squirrel highway.”

Repellents

Naphthalene (moth balls) may temporarily discourage squirrels from entering attics and other enclosed spaces. Use of naphthalene in attics of occupied buildings is not recommended, however, because it can cause severe distress to people. Supplement this method with lights. A cat in the attic may discourage squirrels.

Ro-pel is a taste repellent that can be applied to seeds, bulbs, and flowers; trees and shrubs; poles and fences; siding and outdoor furniture. Capsaicin is also a taste repellent, registered for use on maple sap collecting equipment.

Polybutenes are sticky materials that can be applied to buildings, railings, downspouts, and other areas to keep squirrels from climbing. They can be messy. A preapplication of masking tape is recommended.

Toxicants

None are registered.

Fumigants

None are registered.

Trapping

A variety of traps will catch squirrels, including No. 0 or No. 1 leghold traps, the “Better Squirrel and Rat Trap,” box traps, and cage traps. Regular rat-sized snap traps will catch flying squirrels and small pine squirrels. Glue traps for rats will catch small squirrels.

Since squirrels are classified as game species in most states, trapping permits may be required from your local state wildlife agency or municipal Animal Control office. Wire cage traps and box traps can be used to capture squirrels alive. Tie trap doors open for 2 to 3 days to get squirrels accustomed to feeding in the traps. Then set the traps and check them twice daily. Inform your neighbours of your trapping activities. Translocation of tree squirrels is a questionable practice because of the stress placed on transported and resident squirrels and concerns regarding the transmission of diseases.

Good baits are slices of orange and apple, walnuts or pecans removed from the shell, and peanut butter. Other foods familiar to the squirrel may also work well, such as corn or sunflower seeds.

Shooting

Where firearms are permitted, shooting is effective. A shotgun with No. 6 shot or a .22-caliber rifle is suitable. Check with your state wildlife agency for regulations pertaining to the species in your area.

Questions:

Define non insect pest. Enlist non-insect pest.
Give nature of damage and control measures for rodents (rats and Bandicoots).
Give nature of damage and control measures for snails and slugs.
Explain role of birds as non-insect pest and their control.
What is mollusicides? Give any one mollusicide preparation as poison bait for control of snails.
What is rodenticide? Give any one rodenticide preparation as poison bait for control of rats.
Give control of crabs.

***

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Zoology for you

Sunday 17 August 2014

SYBSc Zoo II Notes : Agricultural pests chapters 1 to 3

Primary pests

Secondary pests

b) Red Cotton Bug

· Distribution: The red cotton bug has wide distribution; it is a minor pest in cotton growing region of northern India particularly Punjab and Uttar Pradesh. This pest also occurs throughout the Maharashtra state but is minor importance. It is commonly known as a “cotton stainer”.

· Marks of Identification:

Egg: Eggs are laid in moist soil or in crevices in the ground. They are spherical and bright yellow in colour.

Nymph: Nymphs are red coloured with black median dorsal spots on the inter-tergal membrane of 3/4, 4/5 and 5/6 abdominal segments. There is a pair of white dorsal spot on each of the third, fourth and fifth tergal plates on the abdomen. The nymphs are smaller than adults and are wingless.

· Host Plants : Cotton, bhendi, ambadi, hollyhock and several other malvaceous plants.

· Nature of Damage:

Control Measures:

Cultural Practices

1. Cotton field should be ploughed to expose eggs to sunlight.

2. Insects should be handpicked and killed in kerosene water.

3. The crops of bhendi should be sown as trap crop and pests collected there, should be destroyed.

4. Moistened cotton seeds should be hanged up at different places in the field where bugs congregate, they may get killed in the kerosene water.

Chemical control

1. Spraying of Malathion 0.05% is effective to control the pest.

2. Spraying of 1 liter endosulfan 35% EC, 0.25 liter phosphamidon = 100% EC or 1 liter Fenitrothion 100% EC per hectare is very effective or reduce pest population.

c) BRINJAL FRUIT BORER:

International Common Names

Prevention and Control

f. RICE WEEVIL/BLACK WEEVIL (Sitophilus oryzae Linn.)

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