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Krushi Sutra 1 Krushi Sutra EXERCISE NO. 2 STUDIES ON PESTS OF CITRUS | NAVTS Krushi Sutra App EXERCISE NO. 1 CLASSIFICATION AND CATEGORIES OF PESTS Insects of economic importance A. Injurious insects a) Pests of cultivated plants (Crop pests) Each cultivated plant harbors many insects pests which feed on them reduce the yield of the3 crop. Field crops and horticultural crops are attacked by many insect species. e.g. cotton bollworm, Rice stem bores. b) Storage pests Insects feed on stored products and cause economic loss. e.g. Rice weevil, Pulse beetle. c) Pest attacking cattle and domestic animals Cattle are affected by pests like Horse fly, Fleshfly, Flese and Lice. They suck blood and sometimes eat the flash. d) House hold and disease carrying insects House hold pests include cockroach, ants, etc. Disease carrying insects are mosquitoes, houseflies, bed bugs, fleas etc. B. Beneficial insects a) Productive insects i) Silk worm The silk worm filament secreted from the salivary gland of the larva helps us in producing silk. ii) Honey bee Provides us with honey and many other byproducts like bees wax and royal jelly. iii) Lac insects The secretion from the body of these scale insects is called lac. Useful in making vanishes and polishes. iv) Insects useful as drugs, food, ornaments etc, (a) As medicine e.g. Sting of honey bees- remedy for rhenmatism and arthritis Eanthoridin - extracted from blister beetle –useful as hair tonic. (b) As food - for animals and human being. For animals- aquatic insects used as fish food. Grass hoppers, termites, pupae of moths. They have been used as food by human beings in different parts of the world. (c) Ornaments, entertainers Artists and designers copy colour of butterflies. Beetles worm as necklace. Insect collection is a hobby (d) Scientific research Drosophila and mosquitoes are useful in genetic and toxicological studies respectively. (II) Helpful insects These are small insects which feed and live on harmful insects by completing their life cycle in a host and kill the host insect. e.g. Egg, larval and pupal parasitoids (ii) Predators These are large insects which capture and devour harmful insects. e.g. Coccinellids, preying mantids. (iii) Pollinators Many cross pollinated plants depend on insects for pollination and fruit set. e.g. Honey bees, aid in pollination of sunflower crop. (iv) Weed killers Insects which feed on weeds kill them thereby killers. e.g. Parthenium beetle eats on parthenium. Cochineal insect feeds in Opuntia dillenii. (v) Soil builders Soil insects such as ants, beetles, larval of cutworms, crickets, collum bola, make tunnels in soil and facilitate aeration in soil. They become good manure after death and enrish soil. (vi) Scavengers Insects which feed on dead and decaying matter are called scavengers. They important for maintaining hygine in the surroundings. e.g. Carrion bettles, Rove beetles feed on dead animals and plants. d) House hold and disease carrying insects Pests which cause damage to belongings of human being like furniture, wool, paper etc. e.g. Cockroaches, furniture beetle, sliver fish etc. Pests which cause painful bite, inject venoms. e.g. Wasps, bees sting us. Hairy caterpillar nettling hairs are poisonous. Mosquitoes, bugs bite, piece and suck blood from us. Disease causing Mosquito- Malaria, Filariasis ,dengue fever. Housefly- Typhoid, Cholera, Leprosy, Anthrax Categories of pests 1. Regular pests: Occurring more frequently on a crop having close association with the crop. (eg) Brinjal shoot and fruit borer. 2. Occasional pests: Occurring infrequently with no close association with a particular crop (eg) Snake gourd semilooper. 3. Seasonal pests: Occurring during a particular part of the year. (eg) Red Hariy Caterpillar (RHC) in groundnut. 4. Pesistent pests: Occurring on a crop almost throughout the year (eg) thrips on chillies. 5. Sporadic pests: Occurring in a few isolated localities (eg) coconut slug caterpillar. 6. Epidemic pests: Occurring in severe form in a region or locality at a particular season (eg) RHC in groundnut in Bhavan Taluk. 7. Endemic pests: Occurring regularly and confined to a particular area or locality (eg) rice gall midge in Madurai dist. (i) Parasitoids
Krushi Sutra 2 Krushi Sutra EXERCISE NO. 2 STUDIES ON PESTS OF CITRUS | NAVTS Pesticide Application Methods The desired effect of pesticide can be obtained only if it is applied by an appropriate method in appropriate time. The method of application depends on nature of pesticide, formulation, pests to be managed, site of application, availability of water etc. 1. Dusting Dusting in carried out in the morning hours and during very light air stream. It can be done manually or by using dusters. Some times dust can be applied in soil for the control of soil insects. During is cheaper and suited for dry land crop pest control. 2. Spraying Spraying is normally carried out by mixing EC (or) WP formulations in water. There are three types of spraying. 3. Granular application Highly toxic pesticides are handled safely in the form of granules. Granules can be applied directly on the soil or in the plant parts. The methods of application are a) Broadcasting: Granules are mixed with equal quantity of sand and broadcasted directly on the soil or in thin film of standing water. (eg) Carbofuran 3%G applied @ 1.45kg/8 cent rice nursery in a thin film of water and impound water for 3 days. b) In furrow application: Granules are applied at the time of sowing in furrows applied @ 3 g per meter row for the control of sorghum shootfly. c) Side dressing: After the establishment of the plants, the granules are applied a little away from the plant (10-15 cm) in a furrow. d) Spot application: Granules are applied @ 5 cm away and 5 cm deep on the sides of plant. This reduces the quantity of insecticide required. e) Ring application: Granules are applied in a ring form around the trees. f) Root zone application: Granules are encapsulated and placed in the root zone of the plant. (eg) by mixing it with equal quantity of sand in the central whorl of crops like sorghum, maize, sugarcane to control internal borers. g) Pralinage: The surface of banana sucker intended for planting is trimmed. The sucker is dipped in wet clay slurry and carbofuran 3G is sprinkled (20-40 g/sucker) to control burrowing nematode. 4. Seed pelleting/seed dressing The insecticide mixed with seed before sowing (eg.) sorghum seeds are treated with chlorpyriphos 4ml/kg in 20 ml of water and shade dried to control shootfly. The carbofuran 50 SP and imdacloprid is directly used as dry seed dressing insecticide against cotton sucking pests. 5. Seedling root dip It is followed to control early stage pests (eg) in rice to control sucking pests and stem borer in early transplanted crop, a shallow pit lined with polythene sheet is prepared in the field. To this 0.5 kg urea in 2.5 litre of water and 100 ml chlorpyriphos in 2.5 litre of water prepared separately are poured. The solution is made upto 50 1 with water and the roots of seedlings in boundless are dipped for 20 min before transplanting. 6. Sett treatment Treat the sugarcane setts in 0.05% malathion for 15 minutes to protect them from scales. Treat the sugarcane setts in 0.05% Imidacloprid 70 WS @ 175 g/ha or 7 g/l dipped for 15 minutes to protect them from termites. 7. Trunk/stem injection This method is used for the control of coconut pests like black headed caterpillar, mite etc. Drill a downward slanting hole of 1.25 cm diameter to a depth of 5 cm at a light of about 1.5m above ground level and inject 5 ml of monocrotophos 36 WSC into the stem and plug the hole with cement (or) clay mixed with a fungicide. Pseudo stem injection of banana, an injecting gun or hypodermic syringe is used for the control of banana aphid, vector of bunchy top disease. 8. Padding Stem borers of mango, silk cotton and cashew can be controlled by this method. Bark of infested tree (5x5 cm) is removed on three sides leaving bottom as a flap. Small quantity of absorbent cotton is placed in the exposed area and 5-10 ml of Monocrotophos 36 WSP is added using an ink filler. Close the flap and cover with clay mixed with fungicide. 9. Swabbing Coffee white borer is controlled by swabbing the trunk and branches with lindane 1 per cent suspension. 10. Root feeding Trunk injection in coconut results in wounding of trees and root feeding is an alternate and safe chemical method to control black headed caterpillar, eriophyid mite, red palm weevil. Monocrotophos 10 ml and equal quantity of water are taken in a polythene bag and cut the end (slant cut at 45) of a growing root tip (dull white root) is placed inside the insecticide solution and the bag is tied with root. The insecticide absorbed by root, enter the plant system and control the insect. 11. Soil drenching Chemical is diluted with water and the solution is used to drench the soil to control certain subterranean pests. (eg) Chlorpyriphos / dimethoate used against cutworms, soilmealy bug. 12. Capsul placement The systemic poison could be applied in capsules to get toxic effect for a long period. (eg) In banana to control bunchy top vector (aphid) the insecticide is filled in gelatin capsules and placed in the crown region. 13. Baiting The toxicant is mixed with a bait material so as to attract the insects towards the toxicant. A) Spodoptera. A bait prepared with 0.5 kg molasses (jiggery), 0.5 kg carbaryl 50WP and 5 kg of rice bran with required water (3 litres) is made into small pellets and dropped in the field in the evening hours. B) Rats: Zinc phosphide is mixed of 1:49 ratio with food like popped rice or maize or cholam or coconut pieces (or) warfarin can be mixed at 1:19 ratio with food. Ready to use
Krushi Sutra 3 Krushi Sutra EXERCISE NO. 2 STUDIES ON PESTS OF CITRUS | NAVTS cake formulation (Bromodiolone) is also available. C) Coconut rhinoceros beetle: Castar rotten cake 5 kg is mixed with insecticide. 14. Fumigation Fumigants are available in solid and liquid forms. They can be applied in the following way. Soil: To control the nematode in soil, the liquid fumigants are injected by using injecting gun. Storage: Liquid fumigants like Ethylene dibromide (EDB), Methyl bromide (MB), carbon tetrachloride etc. and solid fumigant like Aluminium phosphide are recommended in godowns to control stored product pest. Trunk: Aluminium phosphide ½ to 1 tablet is inserted into the affected portion of coconut tree and plugged with cement or mud for the control of red palm weevil. EXERCISE NO. 2 STUDIES ON PESTS OF CITRUS 1. Lemon butterfly : Papilio demoleus Linn., Papilio polytes, Papilio helenus ( Papilionidae : Lepidoptera ) Economic Importance: It causes severe damage to citrus particularly in nurseries. Marks of Identification: Butterfly has yellow and black markings on wings Larva : Green colour and measures 38 mm, five larval instars. Early instar larva is dark with white patches resembling the “dropping of birds” when grown up it turns deep green in clolour. The larval stage lasts for 11- 14 days. When disturbed they protrude two fleshy horns from the neck (Osmeterium). P.demoleus is a big beautiful butterfly with yellow and black markings on all the four wings, having wing expanse of about 50-60 mm. Its hind wings have a brick red oval patch near the anal margin and there is no tail like extension behind though common in Papilionidae. P. polytes males are black and females vary in form. P. helenus has black wings with three white distal spots. Host plant: All citurs species and other plants like bael, ber, curry leaves, bawachi etc. Life History: Eggs: Greenish yellow colour 70 – 180, singly on tender leaves, I.P.: 3- 7 days. Larva: L.P. 2 weeks Pupa : Pupation on plant, remain attached by silken threads P.P. : 10-15 days, may extend upto 2- 3 months in winter It pupates in a necked chrysalis attached to the plants by two fine strands of silk in the form of girdlers. No. of Generations : 4 year. Nature of Damage: Caterpillars feed on tender leaves right upto the midrib and defoliate the plants in case of severe infestation. Natural Enemies: The egg parasitoids associated with this pest are Trichogramma evanesens Westwood (Trichogrammatidae), Ptromalus luzonesis (Petromilidae) and Telenomus sp. (Seclionidae). The larvae are attacked by yellow wasp Polistates herebreus and the praying mantid Crebractor gemamatus, the larval parasite is Charops sp. and Brachymeria sp. is parasitic on its pupa. Management Practices : Cultural control: Grow attractant plants: Carrot family, Sunflower family, Buck wheat, hairy vetch, alfalfa, corn, shrubs( Lace wing) Nectar rich plants with small flowers i.e. anise, caraway, parsley, mustard ,Sun flower, hairy vetch, buck wheat and cowpea(Braconid wasp) Mechanical control: Hand pick the larvae and destroy. Biological control: Conserve the parasitoids such as Trichogramma evanescens. Telenomus spp on eggs Brachymeria spp, Cotesia on larvae and Pterolus sp. on pupae. Chemical control: Foliar spray Malathion @ 1 ml/ lit., Quinalphos 25%EC@ 2 ml/l of water
Krushi Sutra 4 Krushi Sutra EXERCISE NO. 2 STUDIES ON PESTS OF CITRUS | NAVTS 2. Leaf miner: Phyllocnistis citrella. S. (Phyllocnistidae: Lepidoptera.) Economic Importance: Most destructive pests, active in monsoon season, infestation noticed in seedling stage. The pest in suspected to be responsible for the spread of bacterial infection causing ‘citrus canker’ Marks of Identification: Moths: Small, silver white colour, forewings with brown strip & prominent black spot near the tip. Caterpillar: Yellow in colour with brown mandibles, apodous, passes through four instars Host Plants: All citrus species. Life History : Eggs : singly on underside of leaves I.P. : 3 – 6 days. Larva : 1 – 2 weeks. Pupa : Pupation inside the larval mines of leaves P.P. 3 – 4 weeks. No. of generations : 9 – 13 / year.(Pest is active in monsoon season.) Population of the pests decreases during hot summer months. Nature of Damage: On hatching, the larva feed on leaf tissues between upper and lower surfaces of leaves making glistering zigzag tunnels. The leaves turn pale, curl & finally dry. Besides, mined leaves may get bacterial infection, which leads to ‘citrus canker’. Management Practices : Mechanical control: Use pheromone trap @ 5/acre. Pruning of affected parts during winter and burning Removal of infested leaves and their proper disposal in the initial stage. Chemical control: Carbofuran3%CG @ 20000g/acre Foliar spray with Imidacloprid 17.8% SL@ 50ml and use spray volume depending on size of tree &Protection equipment used Foliar spray Permethrin25% EC @160-240 ml in 400 l of water/acre Granular application with Phorate 10% CG @ 6000 gm/acre Biological Control: Natural Enemies: The larvae are parasitised by Cirrospiloideus phyllocnistodes, the euliphod parasitoid’s Cirripilus quadristriatus and tretrachus phyllocnistoides. 3. Citrus psylla: Diaphorina citri K. (Psyllidae : Hemiptera) Economic Importance: Most destructive of all pests of citrus, also transmit “Greening Melody”, a micoplasma disease in citrus. Marks of ifentification: Adults: Small, dark brown in colour and measures 2.4 mm long. Wings are folded like roof over body. They remain mostly on the under surface of leaves with their heads almost touching the surface and rest of the body raised up Host plants: Citrus & other plants belonging to family Rutaceae.i.e Curry leaves Life History: Eggs: In the folds of half opened leaves and leaf axis, 800, orange colour elongate thicker at the basal end anteriorly it is slightly curved & tapering I.P. : 4-6 days summer & 22 days in winter. Nymph: They are light yellow with an orange tinge in the region of abdomen, five nymphal instars N.P. 2 weeks in summer & 3-4 weeks in winter. Adult: Longevity may extend over 6 months. The insect is active from February and increase during March-April. It disappears by about the middle of October. In a year there are about 9 generations. C.O.: Pests over wintering in adult stage. Nature of Damage: Both nymph & adult suck the cell sap from tender leaves, shoot & buds, which as a result curl, dry up & ultimately drop down. Complete crop failures are reported in case of servere infestation. Honeydew exertion of the nymphs favours multiplication of black sooty mould (Capnodium sp.) on the leaves. Management Practices : Mechanical control: Collect and destroy the infested plant parts Biological control: Conserve parasitoids such as Tamarixia radiata, Diaphorencyrtus aligarhensis Conserve predators such as Chrysoperla carnea, Coccinellids, Syrphids. Chemical control: Systemic insecticides like imidacloprid 17.8%SL@ 50ml depending on size of tree & Protection equipment used are very effective at controlling both the nymphs and the adults. Foliar spray Thiamethoxam 25%WG@40g in 400 l of water/acre. Foliar spray with Oxydemeton-methyl25% EC @ 600-800ml in 600-800 l of water/acre 4. White fly: Dialeurodes citri A. Black fly: Aleurocanthus woglumi A (Aleurdidae: Hemiptera) Economic Importance: White fly, D. citri is common occurrence & destructive pest of citrus. It causes ‘Kolshi’ in citrus & reduce plant vigour. Marks of Identification: White fly: Adult: Minute insect with yellowish body & red eyes. Wings white or greyish, covered with mealy secretions. The longetivity of adults is about 2 to 8 days. Black fly: dark orange with smoky wings and fore wings having four whitish areas of irregular shape. Nymphs : Oval shaped, scale like & blackish with marginal bristle like fringes. Black fly: Smaller in size & black, in colour. Host Plant: Citrus, cotton, Castor Banana, Coffee & some ornamental plants. Life History: Eggs: Underside of leaves, I.P. 10 days. Nymph: N.P. 3 – 10 weeks. Pupa: Pseudo pupa (Quiescent stage) on underside of leaves, P.P.: 16 – 22 weeks. Nature of Damage: Nymphs & adults of flies suck the cell sap from leaves, as a result leaves wither & turn brownish. Nymphs excrete honeydew on which black sooty mould develops. The blackish coating commonly called “Kolshi”. Fruit setting is adversely affected in case of severe infestation. Management Practices : White Fly Cultural control: A regularly maintained program of hedging and topping can help avoid whitefly problems. Biological control: Parasites and predators attack the citrus whitefly Chemical control: Oxydemeton–methyl 25% EC @600-800 ml in 600-800 l of water/acre