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Insect Pests of Important Crops – Essay

Nature of Damage:

The Larva tunnels into the stem causing ‘dead heart’. Its multiplication is favoured by high temperature and low humidity.

Life History:

The small pale grey brown moth with white hind wings. The egg, larval and pupal periods respectively 6, 25-30 and 6-8 days. The total life cycle is completed in 35 to 40 days.

Control:

Infested tillers collected and destroyed. Avoid late planting.

2. Stem borer (or) internode borer: chilo sacchariphagus indicus

Nature of Damage:

It occurs on sugarcane in its growing phase. It affects juice quality.

Life History:

Egg (5-6 days) – Larva (37-53 days) – Bores (nodal – pupa region) (in leaf sheath (8-10 days)

– Adult (Pale brown)

Control:

Release of egg parasite Trichogramma australicum.

3. Top Borer:

Scripophaga excerptalis

Nature of Damage:

It occurs in later stages of growth. Its infestation, is detected by presence of a reddish brown charred ‘dead heart’.

Life History:

Egg (7-9 days) – Larva (35-50 days) – Pupa (8-10 days) (inside Stem)

-Adult (Whitish in colour with buff coloured anal tuft)

Life cycle 50-70 days.

Control:

i. Egg masses collected and destroyed.

ii. Soil application of carbofuran at 2 kg a.i/ ha.

4. Sugarcane Leaf Hopper:

Pyrilla Perpusilla

Nature of Damage:

It remains colonies on the lower surface of leaves and both the adults and nymphs suck up the sap causing yellowing and drying of leaves.

Life History:

Egg – Nymph (50-60 days)- Adult (brownish)

Control:

Endosulfon 0.07% spray.

Cotton:

1. Cotton Aphid:

Aphis Gossypii

Nature of Damage:

It infest tender shoots and the undersurface of leaves severe infestation results in curling of leaves, stunted growth and gradual drying and death of young plants.

Life History:

Nymphs (7-9 days) – Adults (greenish brown)

Control:

i. Methylparathion 0.025 %

ii. Phosalone 0.05%

2. Cotton Leaf Hopper:

Amrasca Devastans

Nature of Damage:

The nymphs and adults suck the plant sap from the undersurface of leaves. The leaves show symptoms of ‘hopper burnt’ such as yellowing, curling and bronzing.

Life History:

Eggs (4-10 days)- Nymphs (7-20 days)- Adult

Control:

i. Methyl parathion 0.025 %

ii. Phosalone 0.05%

3. Cotton white fly:

Bemisia tabaci

Nature of Damage:

The nymphs are found on the undersurface of leaves and drain of sap due to sucking in cases of severe infestation result in premature defoliation and development of sooty mould on honey dew excretion.

Life History:

Eggs (3-5 days) – Nymphs (9-14 days)- Pupa(2-8 days) – Adult

Control:

Spray applications of phosalone 0. 05% + neem oil 0.3%.

4. Spotted boll worm: Earias insulana

Nature of Damage:

The larva causes drying of the shoot due to its feeding by boring into it. Heavy shedding of early formed flower buds due to this pest.

Life History:

Eggs (under surface of leaves (3 days) – Larva (10-12days) – pupa (7-10 days)-Adult,

Total life cycle – 20-22 days.

Control:

i. The infested portions of buds and bolls should be removed and destroyed.

ii. Synthetic pyrethroids like permethrin @ 100-150 g ai/ha and cypermethrin @ 80 g ai/ha.

5. Pink boll worm: –

Platyedra gossypiella

Nature of Damage:

The larva enters the developing boll through the tip portion and the entrance hole gets closed up as the boll matures. The infested flower buds shed prematurely. A rosette shaped bloom ware found.

Life History:

Egg (4-25 days) – Pink larva (20-35 days)- Pupa (6-20 days) – Small dark brown mont.

Control:

i. Attacked parts collected and destroyed

ii. Fumigation of seeds with methyl bromide at 1.5 kg/100 cum for 24 hrs.

Rice:

1. Rice stem borer: Scirpophaga incertula

Nature of Damage:

The larva feeds inside the stem causing drying of the central shoot or ‘dead heart’ in young plant and drying of the panicle or ‘white ear’ in older plant.

Life History:

Eggs (5-8 days)- Larva (dark brown head (35-40 days) – Pupa (inside the stem (6-10 days)

– Adult moth

Total life cycle 50-70 days.

Control:

i. Removal and destruction of rice stubbles from field.

ii. Collection and destruction of egg masses.

iii. Moths may collected by setting light traps.

2. Swarming Caterpillar: Spodoptera mauritia

Nature of Damage:

The leaves are completely eaten away leaving behind the midribs of leaves. They feed mostly during night.

Life History:

Egg – Larva (20-25days) – Pupa (10-15days) – Adult (dark Colour moth)

Control:

i. Flooding the nursery makes the hiding larvae to come to the surface

ii. Spray application of methyl parathion 0.05%.

3. Rice Gall Midge: orseolia oryzae

Nature of Damage:

It is popularly known as ‘Silver shoot’ or ‘onion shoot’ because of the formation of hollow pink, dirty white cylindrical tubes bearing at their tips a green reduced leaf blade.

Life History:

Eggs (3-4 days) – Maggots (15-20 days) – Pupa (2-8 days) – Adult (Yellowish brown fly

Control:

Spray application at 0.5/kg ai/ha are chlorfenvinphos and dicrotophos.

4. Rice mealy bug: Heterococcus rehi

Nature of damage:

Its infestation causes round patches in a normal crop and plants have distorted panicles with chaffy grains.

Life History:

Eggs – Nymphs (17-35 days)

Control:

i. The grass on the field bunds should be removed.

ii. The infested plants should be removed and destroyed.

5. Rice leaf roller: Cnaphalocrocis medinalis

Nature of Damage:

The larva rolls the leaf blade by fastening its edges. In a severely infested field the whole crops give a sickly appearance with white patches.

Life History:

Eggs (4-7 days) – Larva (15-25 days) – Pupa (6-8 days) – Adult (Brownish orange colour moth)

Control:

i. Removal of grass

ii. Periodical spray application of dicrotophos and chlorpyriphas at 0.5 kg ai/ha.

Wheat:

Termites:

Odentetermes Obesus

Nature of Damage:

Attack young seedling, wither and die.

Control:

Partially decomposed manure should be avoided apply Endosulfan 25 kg/ha.

Aphids:

Macrosiphum miscanihi.

Nature of Damage:

Nymphs and adults suck sap from tender shoots, immature grain and result in poor yield.

Control:

Avoid heavy manure, and succulent crop, 0 02% dimethoate.

Stemborer:

Sesamia inference

Nature of Damage:

Dead heart

Control:

Pullout and destroy dead hearts, dust 0-05% sulfur.

Ground Nut:

1. Red hairy cater pillar: Amascta albistriga

Nature of Damage:

The larvae feed the under surface of tender leaflets and they also feed nature leaves leaving behind the petiole and mid ribs of leaves.

Life History:

Eggs (2-3 days) – Larva (40-50 days) – Pupa – Adult

Control:

i. Pupae collected and destroyed during summer ploughing.

ii. Putting light traps to attract moths.

iii. Larval parasites like Apanteles flavipes and Apanteles bosei.

2. Leaf minor: stomoperyx subrecivella

Nature of Damage:

The larva mines into tender leaf lots and feeds on the tissue. In a severely infested crop the whole field presents a burnt up appearance.

Life History:

Eggs (3days) – Larva 14 days) – Pupa – Adults

Control:

i. Putting light traps to attract adults.

ii. Spraying Fenitrothion 0.025% or phosalone 0.05%.

3. Stem borer: Sphenoptera perotetti

Nature of Damage:

The grubs of the dark brown shining beetle bore into the stem of groundnut plants and cause wilting and drying of plants.

Control:

The infested plants should be collected and destroyed.

Coconut:

1. Rhinoceros beetle: Oryctes rhinoceros

Nature of Damage:

The adult beetle cut across the leaf in the leaflets. Frequent infestation results in stunting of trees and death of growing point in young trees.

Life History:

Eggs (8-15 days) – Larval grub (90-180 days) – Pupa (10-25days) – Adults

Life cycle – 3 to 8 months.

Control:

i. Decaying trunk of trees should be burnt

ii. Castor cake @ 1 kg soaked in water in small mud pots attracts beetles.

2. Black headed cater pillar: Opisina arenosella

Nature of Damage:

Larvae live on the undersurface of leaf lots within galleries of silk material and feed by scraping the green matter.

Life History:

Eggs (1-5days) – Larva (40 days) – Pupa (12 days) – Adult (Greyish white Small moth)

Control:

i. For young trees spray carbaryl 0.1%.

ii. Releasing parasitoid such as perisierola and Trichospilus pupivora.

3. Red Palm weevil: Rhyncophocus ferrugineus

Nature of Damage:

It attack the central shoot shows sign of wilting. In the grown up trees the crown region is infested.

Life History:

Eggs (2-5days) – Grub (35 – 75days) – Pupa (12-35days) Adult (reddish brown weevil)

Control:

i. Damaged palms should be destroyed.

ii. The infested portion should be scooped out.

Pests of Vegetables:

Brinjal:

1. Shoot and fruit borer: Leucinodes orbonalis

Nature of Damage:

The larva bores into tender shoots in the early stage and causes ‘dead hearts’. It also bores into flower buds and developing fruits.

Life History:

The moth has brownish and red markings on the whitish forewings. The female lays eggs on tender shoots and developing fruits. The egg, larval and pupal periods respectively 5, 15 and 6-8 days.

Control:

The damage portions should be removed.

Periodical spray application of phosalone .07%.

2. Stem borer: Euzophera perticella

Nature of Damage:

The larva bores into the stem and covers the hole with excreta. The plants become stunted growth and the infestation is generally noticeable in the later stage of crop growth life history.

The moth has greyish brown fore wings and transverse lines in the middle wings. The yellowish larva with a red head. Life cycle ranges from 26 to 55 days.

Control:

The attacked plants should be removed periodical application of carbaryl 0.1%.

3. Spotted leaf beetle: Epilachina vigintioctopunctata

The grubs and adults scrape the leaves and feed.

Life History:

The female lays eggs in group of 10 to 20 on the under surface of leaves. The egg period is 2-4 days. The yellowish spiny grubs become full grown in 10-20 days. The total life history takes 15-40 days.

Control:

Spray application of carbaryl 0.1% malathion 0.1 %.

4. The Grey weevil: Myllocerus subfasciatus

Nature of Damage:

The adult beetles feed on leaves of brinjal; the grubs feed on roots and cause wilting and death plants.

Life History:

The weevil lays eggs in the soil. The incubation period is about a week. The grubs become full grown in 2 months. The adults emerge in 10-20 days.

Control:

The adult beetles should be collected and destroyed or killed by dust application of carbaryl.

Cucurbits:

1. Snake gourd semilooper:

Plusia peponis

Life History:

The brownish moth has shiny brown fore wings. The caterpillar is greenish with white longitudinal lines. The pupa is greenish but turns dark brown before the emergence of the adult moth. Life history occupies around 1 month.

Control:

The larvae when found in small numbers may be hand picked and destroyed. Spray application of parathion .025% controls the pest.

2. Snake gourd stem weevil:

Baris trichosanthis

The small black weevil feeds on the green leaves. It lays eggs in nodes. The incubation period is 5-6 days. The grubs bore into the stem and cause damage.

3. Fruit flies:

Dacus cucurbitae

Nature of Damage:

It is slightly bigger with brown marking on wings. The maggots feed on the contents of fruits and cause premature dropping of fruits. The insects attack the fruits of snake gourd, bitter gourd etc.

Life History:

It lays eggs on flowers or tender fruits. The maggots that hatch out from the eggs in 2-9 days feed on the seeds of the fruit. The larval and pupal periods occupy respectively 3 and 5 days. The total life history occupy 12 to 35 days.

4. Pumpkin beetles:

Raphidopalpa foveicollis

Nature of Damage:

The beetles bite holes on leaves and also feed on flowers. The roots as well as the stem and fruits that come in contact with the soil are damaged by the grubs.

Life History:

The brownish eggs are laid in the soil. The egg period is 5 to 8 days. The grubs become full grown in 13-25 days and pupae in the soil. The pupal period from 7 to 17 days.

Cole Crops:

Cabbage:

1. The diamond back moth:

Plutella Xylostela

The larvae bite leaves and cause serious damage.

Life History:

The moth is greyish brown with narrow wings having pale white markings anteriorly which form diamond like white patches. It lays eggs on the undersurface of leaves. The larva is greenish. The period from egg to adult is 25 to 35 days.

2. The Cabbage borer:

Hellula undalis

Nature of Damage:

The larvae web the leaves or bore into stem and cause damage.

Life History:

The moth lays eggs on the leaves and hatch in about 4 days. The brownish larva has a black head. It becomes full grown in about 9 days and pupates in the soil. Pupal period is about 6 days.

Radish:

1. Leaf webber:

Crocidolomia binotalis

Nature of Damage:

The larvae remain undersurface of leaves in webs and feed on them. They also attack flower buds and pods.

Life History:

The small moth with light brownish fore wings lays eggs in masses. The incubation period ranges from 5-15 days. The larval becomes full grown in 20-25 days. Pupates emerges as adult in 14 to 40 days.

2. Painted bug:

Bagrada Cruciferarum

Nature of Damage:

The nymphs and adults suck the sap from leaves, shoots and pods.

Life History:

The bug is small, black in colour with red and yellow lines. It lays barrel shaped brownish eggs. The egg and nymphal periods take respectively 1 and 3 weeks.