Pest Management

Cotton
pest

Whitefly

Jassid

Aphids

American Bollworm

Pink Boll- worm

Spotted Boll-worm

Red cotton bug

Cotton leaf roller

Dusky cotton bug

Grey weevil

Cotton stem weevil

Cotton stem borer

Thrips

Surface grass hopper

Nematodes

Picture showing nature of damage
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Economic Threshold Level (ETL) and Damaging stage

10 adults flies per leaf or 20 nymphs per leaf
Nymphs and adults

2-3 adults per leaf Nymphs and adults

2 adults per leaf or 15-20% affected plants Nymphs and adults

10 larvae per 20 plants during early fruiting phase 20 larvae per 20 plants when boll formation is at its peak Caterpillar

5% damaged fruiting parts Caterpillar

5% damaged leaves, flowers,squares etc. Caterpillar,

Nymphs and adults

Caterpillar

Nymphs and adults

Grubs

Grubs

Grub

10 nymphs or adults per leaf Nymphs and adults

Hoppers and adults

Nature of damage
 

Nymphs and adults suck the sap from the leaves; affected leaves curl and dry up; growth is stunted; also the flies act as vector of virus diseases.

Nymphs and adults found on the underside of the leaves, sucking the sap; leaves turn yellow and start curling; in severe cases the leaves turn chocolate red and crumple; in such cases, the growth of plant is also stunted.

Nymphs and adults appear in colonies on the tender portions of plants, sucking the sap; affected leaves curl and plants get deformed and stunted.

Destructive pest, caterpillar borer into square flowers and boll and feed within the boll. While feeding head of caterpillar is inside the square or boll and remaining portion is outside the square and boll.

A very destructive pest all over the world; blackish-brown moths whose pinkish caterpillar bore into the bolls and feeds within and pupate therein; immature bolls are shed, whereas the mature ones do not open fully.

Small brown caterpillars bore into the top shoots before boll formation and later into the green bolls; the top shoots droop down and attacked bolls are shed; moths are green winged (E.insulana) or have a green stripe on forewings (E.vittella)

Nymphs and adults are conspicuously red with black markings on the forewings; they suck the sap from the flowers, buds and bolls and taint the lint with faeces. The infested bolls open badly and the quality of the lint is further affected.

Small, greenish-yellow caterpillars roll the cotton leaves and feed within; exotic varieties are more susceptible; moths, medium sized with yellow wings; active from mid July to September.

Nymphs and adults feed gregariously on the sap of immature and partially mature seeds and impart a yellow tinge to the lint; active from early September till harvest and are even carried with the seed-cotton to the ginneries.

Polyhagous; grubs feed on roots whereas adults feed on the margins of leaves, buds and occasionally flowers as well; found on cotton during June to September in northern India.

Small white grubs bore into the stem near the base and cause gall like swellings; attacked plants lodge with strong winds

A Beetle Grub That Bores Into the stem and pupates therein; found during the end of July to August, specially during years of drought

Cause serious damage in certain years; nymphs and adults scrape the green portion of the leaves and suck the sap, resulting in bronze or silvery patches. In severe cases, leaves curl and the growth is stunted; active during May-June in northern India and during August-September in southern India.

Polyhagous; found throughout India; seedlings are cut at the ground level; later the hoppers and adults feed on the leaves (causing shot-holes) till October-November

Worms that feed on or in plant roots, robbing them of nutrients and causing injury, limiting water and nutrient uptake and making the root system more susceptible to other diseases. increased seedling disease (root-knot and reniform nematodes), stunting, lower yield, poor stands, loss of green color, root galling (root-knot), stunted roots (sting and Columbia lance nematodes), and various nutrient deficiency symptoms.

Control
Measures

Sow resistant varieties; spraythe crop fortnightly with 0.02% Phosphamidon, Monocrotophos, Methyl demeton, Dichlorros or Dimethoate, starting with the appearance of the pest; 2-3 sprayings may be necessary.

Same as above

Same as above

When infestation is seen spray following :
pyrethroids perhectare in 500 litres of water:- • Cypermethrin 25%- 200ml or 10%-500ml. • Decamethrin 2.8%- 400ml or 20%- 250ml. If there is infestation of whitefly and jassids do not spray systemic pyrethroids but spray monocrotophos 830ml in 500 litres of water. Also collect fallen squares, flowers and bolls and burn it immediately. If American bollworm is not controlled after spraying of insecticides, spray Heliothis, NPV 450 L.E. per hectare and collect caterpillars and destroy it.

Clean cultivation; expose the seed materials to the sun's heat for 2-3 days before sowing; destroy all fallen buds and bolls, spray, as in the case of spotted bollworms.

Avoid growing lady's finger during the off-season in the vicinity of cotton fields; remove and destroy the attacked shoots and bolls; after harvest, remove all stubble; spray 0.1% Carbaryl and 0.03% Monocrotophos alternately at fortnightly intervals 2-3 times.

Spray 0.04% Monocrotophos or Quinalphos

Hand-picking and destruction of rolled leaves with larvae within; spray 0.1% Carbaryl or 0.04% Monocrotophos; repeat, if necessary.

Spray 0.04% Monocrotophos or Quinalphos Dusting of pholidol/folidol 4-5 per cent 20 kg per hectare

Chloropyriphos 20% EC, 4% dust powder

In infested areas, all cotton plants should be pulled out and destroyed after harvest; avoid growing alternative or collateral host plants during the off-season.

Uproot and burn the withered plants

Spray 0.03% Phosphamidon, Dimethoate, Methyl demeton or Mono- crotophos

Plough deep and scrape the bunds to expose the eggs

by crops like (sorghum, alfaalfa, soyabean for southern root –knot , corn,peanut for leison nematodes, clover, tobbaco alfaalfa for sting nematodes, tobbaco, peanut,milo for Columbia lance,pepper sorghum,corn, urnips mustard soyabean for reniform nematodes etc) Resistance: Deltapine 90 and KC 311 to Columbia lance nematode Paymaster H1560 Georgia 161 to root-knot ematode. Subsoiling (for Columbia lance), regular weeding, cover crops (such as rye or wheat for suppression of reniform and Columbia lance nematodes. Crop 4 to 6 tons per acre of poultry litter effective to supress Columbia lance and root-knot nematodes. Chemical Control: Nematicides like Aldicarb (Temik) 15G 1,3- ichloropropene (Telone II)

Reasons for the squares and boll fall

The growth of the cotton crop is uncertain. During the whole life span of cotton crop the crop bears numerous square and flowers. But among that very few square forms bolls and we get cotton out of it. Different factors of the climate have its effect on the hybrid varieties of cotton due to which square and boll fall takes place.

Following are the reasons given for boll fall in cotton.

  1. Cloudy weather and shade: Cloudy weather and shade which is seen in some parts of the farm causes square and boll fall.

  2. In farm if more irrigation is given to the cotton crop or heavy rainfall occurs then it dose not allow the water to drain from the soil and due to which square and boll fall takes place.

  3. If application of nitrogenous fertilizers is given in a greater percentage it also causes square and boll fall. Hence farmers should avoid excess use of nitrogenous fertilizers.

  4. In a fertile soil if there is less distance between two plants then due to the availability of less sunlight boll fall may take place. Under such circumstances if the excess of plants are removed it helps to give good yield. The distance between two plants is depend upon fertility of soil, hybrid variety which is grown and rainfall receiving in that particular area etc.

  5. Deficiency of micronutrients also can cause square and bolls fall.

  6. Water stress to the cotton crop causes fall in boll and leaves. Hence crop should be irrigated regularly.

  7. Normally when the crop is at the last stage of growth at that time, leaf and boll drop is seen more. If upper part of 4.5-5.0 ft of height is plucked from the main branch then it also helps to control the drop. The height of the plant, which is to be retained, depends on fertility of soil and variety.

Preventive measures to control the leaf and boll drop

  • Use of I.A.A: It is seen that use of IAA (Indol acetic acid) helps to control the leaf and boll drop for e.g. when the crop is in flowering stage or after heavy rainfall spraying with IAA should be done so that leaf and boll drop will not take place.

  • For the availability of micronutrients in the soil, the soil testing should be followed and accordingly fertilization should be given.

  • If after heavy rainfall the crop is seen light yellow in colour then apply 2% urea alongwith IAA helps to control the drop.

Reasons for the 'unopened bolls' in northern part in case of American cotton

In the northern areas like Punjab, Haryana and Rajasthan it is seen that unopened bolls is a common problem. In which the bolls remain small in size and before its maturity, opening of bolls takes place. In such bolls the available cotton is immature and is of no use. following may be the reasons for unopened bolls.

  • Scarcity of nitrogen in sandy soil. This type of problem is seen more in salted soil. In which the sodium salt percentage is more in 2-3ft of soil.

  • In soil (salt containing) the availability of micronutrients like zinc and boron is less and may cause unopenedbolls.

  • To avoid this use of micronutrients should be done properly along with nitrogen and follow following dose.

Urea - 2% (24m/lit of H2O)
Borax- 0.1% (1gm/lit of H2O) for the deficiency of boron
Planofix- 4.5ml (in 10 lit of H2O)
Zinc sulphate- 0.2% for the deficiency of zinc.

Integrated Pest Management for Cotton

Introduction
India ranks first in acreage and fourth in the production amongst major cotton growing countries viz., Russia, China, India, Brazil, Turkey, Egypt, Mexico and Sudan constituting about 85% of the world's cotton production. Most of the pests in cotton that played havoc in cotton growing states. The cotton bollworm, tobacco caterpillar, whitefly, and jassids are some of the major pests of cotton that have potential to reduce yields by 20-80%. The use of agro chemicals to control the pest is become a pragmatic approach for the pest management. Excessive and in discriminate use of insecticides in cotton has led to problems are insecticide resistance, pest resurgence, accumulation of harmful residues and toxicity to non-target organisms. This has prompted the necessities of integrated pest management approach. Following are the approaches IPM.

Pre sowing
Avoid brinjal cultivation or sunflower in cotton crop rotation, to reduce the grubs of ash weevil or whitefly infestations, respectively. Do not stack cotton stalks near fields. Immediately after the season allow animal grazing in fields and ensure timely removal and destruction of cotton stubbles, followed by deep ploughing to expose the carry-over population of bolloworms.

Seed treatment
Destroy the stalks during off-season to prevent carry over of whitefly. Treat seeds with concentrated sulphuric acid to kill hibernating larvae and good germination. Treat seeds with Ceresan wet or Agall 0.1@ 1g/ltr water or treat seeds with Captan or carbendazim @ 2g/kg.

Selection of cultivar
a. For central and south India
Recommended hybrids: NHH-44, PKV HY-2, JK Hy-1, JK Hy-2, H-8, H-10, Ankur-651
Recommendedvarieties: LRA-5166, LRK-5166, LRK-516, PKV-081
Desi types: AKH-4, AKH-8401

b. For North India
Early maturing: F-846, F-1378, LH-1556, F-2054, H-1098,
Recommended hybrids: Omshankar, Fateh, Dhanalaxmi

During sowing
Avoid late sowing to prevent whitefly's flureup and alternate food plants, viz., chillies, lantana weed, many ornaments if at all in the vicinity. Hybrids must be grown in medium-deep soils having good drainage. In Central and South India sowing must be completed by the first week of July. In North India it is preferable to complete sowing operations by the third week of May. If seed treatment is not given apply 10% granulated phorate @ 10kg/ha at the time of sowing (1-1.5 gram at each sowing hill) to control the sucking pest at vegetative growth stage. Grow castor along the border and irrigation channels as indicator or trap crop for tobacco caterpillar. Castor pollen grains and rich in protein, a good source of food for natural enemies like lacewing adults, and lady bird beetles.

Management
a. Cultural methods

  • Immediately after harvest, remove cotton crop and dispose off the residues.

  • Grow cotton once in a year in the proper season. Avoid ratoon and double the cotton crop.

  • Use optimal nitrogenous fertilizers and water to check excessive vegetative growth and consequent pest build up.

  • Avoid malvaceous crops like bhendi, thuththi, oomaththai, tridax poovarasu, etc.

  • Grow trap crops to reduce the pest intensity.

  • Acid delinting of cotton seeds with 10ml of commercial concentrated sulphuric acid/kg of fuzzy cotton seeds to kill eggs, larvae and pupae of pink bollworm.

  • Collect and destroy the larvae collected under the blue cloth spread in the furrows and irrigation channels.

b. Mechanical methods

  • Set up specific pheromone traps at the rate of 12 per hectare e.g. for American bollworm-helilure, pherodin S.L., or spodlure for tobacco budworm and gossyplure for pink bollworm.

  • Set-up light trap of pheromone trap, 10-12 per hectare to monitor the broad activity of bollworm adults.

  • Collection of fallen squares, flowers and fruiting bodies and their storage in a caged corner where bollworms do not come out while emerging out due to natural parasitisation.

  • Collect egg masses of Spodoptera litura, spodoptera exigera or infested shoots with spotted bollworms from cotton as well as caster crop grown on bunds or channels.

c. Biological control

  • Application of NPV in the evening hours 2-3 times at 10-15 days interval @ 450-500 LE/ha reduces the larval population on observing the eggs or larvae of tobacco budworm.

  • Release of Trichogramma chilonies @ 1.5 lakh eggs per hectare in two installments after 60-75 days of crop age. Against bollworm and other Lepidoterious. These are available as Trichocard.

  • Release first install larval (50000 per ha) of either Chrysoperla carnea or Mallado boiensis at 15 days interval, to suppress bollworm, white flies, aphids etc. These larvae may be broadcast along with saw dust or along with corrugated papers 1-2 larvae per plant early in the morning.

  • Inductive release of egg-larval parasite Chilonus blackburnii and the predator Chrysoperla carnea, 1,00,000/ha at 6th, 13th, and 14th week after sowing to manage American bollworm.

d. Chemical

  • During early stages of square formation, spray endosulfan 200 ml in 500 litres of water /ha. During bolling and maturation stage apply any one of the insecticides phosalone 35 EC 2.5 I/ha.or Quinalphos 25 EC 22.0 1/ha. or Carbaryl 50 WP 2.5 kg (1000 I spray fluid)/ha.

  • Apply N.P.V. followed by synthetic pyrethroid like phosaline or endosulphan, which are less toxic to natural enemies. Pyrethroids should be used only once. Synthetic pyrethroids either as over dose or repeated sprays lead to excessive whitefly flareup.

The control measures for pests of cotton.

Pest Economic threshold level for spraying insecticides Rate of insecticides
Aphids, Thrips, Jassids, Whitefly --- Phorate 10% granulated 10 kg per hectare before sowing (1-1.5gram at each sowing hill)
Aphids, Thrips, Jassids Aphids 15-20% infested plants or adults 10 per leaf, thrips 2 per leaf, jassids 10 per leaf Spray methyl dematon 8ml or Phosphamidon 2.5ml or dimethoate 30% 10ml or monocrotophos 15ml in 10 litre of water
Whitefly 2-3 per leaf Spray neem extract 5% or methyl dematon 40ml or monocrotophos 20ml in 10 litre of water
Cotton bollworms 5% or more damaged leaves, flowers, squares etc. Insecticides for 10 litres of water:-
Endosulfan 35% - 20ml or
Quinolphos 25% - 20ml or
Phenvalrate 20% - 5ml or
Cypermethrin 10% - 7.5ml or
Cypermethrin 25% - 3ml or
Dasis 2.8% - 8ml or
Endosulfan 4% dust - 20 kg per hectare

Harvest

Harvest crop timely and avoid extending crop growth beyond its duration or as ratoon which encourage in perpetuating pest problems.