Insect Pests and their Management

Lentil Insect Pest

kiran — Wed, 03 Oct 2018 04:30:43 +0000

Lentil Insect Pest kiran Wed, 10/03/2018 - 10:15

1. Pod Borer (Helicoverpa armigera hunber )

They are the polyphagous pest. The adult moth is of 20 mm long and has brown color. They are active at night

Damage: The larva feed short time on tender leaves by scrapping green tissues and shift to flower buds and tender shoots.

Management: Helicoverpa spp. has many parasites & predators that give adequate control of this pest. In some areas use of pesticide results to increase in population through the reduction of these natural enemies.

Spray with monocrotophous 36% SL , chloropyriphos 20% EC, synthetic pyrethroids and deltamethrin 11% W/W EC ( Decis 380 g/L a.i/ha) and other at the time of flowering and early pod setting

2. Cowpea aphid (Aphis craccivora Koch )

Aphids are serious pest in all lentil growing areas. The adult aphids are dark colored aphids but the appendages are whitish with black tips.They are shiny black sometime with fine dusting of white powder.

Damage: Aphids feed on plant sap, disrupting the normal plant growth pattern including reduction in root and nodulation growth. At high Aphid densities, plants are deformed;stunted and seed set is reduced. A cowpea aphid does not produce toxins or other persistent effects once aphids are removed. Normal plant growth rates are resumed.

Management: Spray with Neem Oil 3000 ppm @ 2ml/l else spray with systemic or contact insecticides to protect susceptible crops. Systemic materials are often applied at planting including Dimethoae 30% EC (400 g a.i/l) at the rate of 0.8 l/ha.

3. Armyworm ( Spodoptera exigua hubner )

Armyworm (S. exigua) is a polyphagous pest. The adult moth body colour greyish brown, forewings and hind wings are semitransparent with a dark margin.

Damage: The larvae feed on the foliage and only severe infestation can defoliate the plants. The army worm rarely causes economic damage in lentil.

Management: Collect and destroy the caterpillar.Spray 500 ml of Dichlorovous 85 SL or 3 kg of carbaryl 50 WP or 1 liter of Quinalphos 25 EC in 500 liters of water per ha.

4. Cutworm ( Agrotis ipsilon hubnagel )

A.ipsilon is a cosmopolitan and a polyphagous pest. The adult moths are grey brown color, large in size with a wingspan of 40 mm. The forewings are light brown color and hind wings are creamy white with brown edges.

Damage: The larvae of cutworm cuts the blant during night and plant are seen fallen during day, sometimes they also carry the fallen plant to the holes where they hide during the day. Some species of A.ipsilon feed on the upper leaves before moving to the soil surface.

Management: Destroying the holes where they harbour. Deep ploughing of the field in between the crops.

Collect and destroy caterpillar mechanically.

Broadcast Bt mixed bait ( 2 gm Bacillus thuringiensis formulation with 1 kg of wheat bran) @ 10 kg of per ha.

5. Bud Weevil ( Apion arrogans wenck )

The bud weevil (A. arrogans) body length is 3 mm and the snout is longer than the body. They are long legs. Colors of adult weevil have dark blue elytra with black head, thorax, legs and abdomen.The species larvae colors are yellow and legless.

Damage: Adult weevils feed on lentil leaves making small holes but the larvae feed mostly bucks and flowers and the ovary is destroyed he larva cab be found inside the buds and which feeds on the developing seeds. The budweevil A.arrogans also transmit broad bean mottle virus (BBMV) in lentil.

Management: The serious infestation is not observed due to bud weevil. The crop rotation, destruction of damaged buds and use of natural enemies are the economic ways to control the weevil. If the population of weevils are high and infestation is more then the monocrotophos 36 SL @ 2 ml/ha is used to control the weevils.

Category

Insect Pests and their Management

Maize Insect Pest

kiran — Wed, 03 Oct 2018 04:30:24 +0000

Maize Insect Pest kiran Wed, 10/03/2018 - 10:15

1. Maize Stem/Shoot Borer - Chilo Partellus

Chilo partellus is a key pest throughout Nepal . These insects are yellowish brown with straw coloured wings with marks, hairy hindwings. The larvae are yellowish brown with a brown head.

In maize, larvae bore holes visible on the stem near the nodes. They cause causing typical “shot hole” symptom. In severe cases, dead hearts are formed and such plants do not bear the ears.

MANAGEMENT:

Release of Trichogramma chilonis at rate of around 1 lakh per hectare
Inter-cropping with legume reduces borer
Clip the lower leaves of maize upto the 4th
Use of safe chemical pesticides/ Seed and At-Planting Insecticide Treatments:

use carbofuran 3G at or before sowing @33 kg per hectare
Fenvalerate 20EC @375ml/ha, Cypermethrin 10EC @650ml/ha in250-500 litres of water as foliar spray
15 kg granular pesticide of fipronil

2. Corn Leaf Aphid - Rhopalosiphum maydis

Maize, also reported to occur on sorghum, wheat, and barley. Yellow, green in color with nymphs are wingless adults with smaller size. Corn leaf aphid acts as a vector of Maize dwarf mosaic virus (MDMV). It causes leaf mottling and discoloration; reddening of corn leaves exacerbated under drought stress. The aphid also produce a sticky honeydew.

MANAGEMENT:

Use Aphilines wasp as parasitoid
Avoid buying infested seedlings for the nursery
Use of mineral oil @15ml/l
Treatment of roots with Malathion, tobacco
use carbofuran 3G at or before sowing @15gm per plant

3. Army worm - Mythimna separate

Armyworms are occasionally a problem in corn, especially in weedy fields, in fields near severely infested small grain, and in no-tillage corn. The adults are pale brown while larvae are voracious, dull-white, green. It causes naked(skeletonized), cut crops. Maximum infestation occurs at rise of springand also damages inflorescence, ear, grains.

MANAGEMENT:

Removal and destruction of weeds
Manual operations: handpicking of large caterpillars, beetles and egg masses and use of sweep nets, wire gauges etc.
flooding irrigation
Use of safe chemical pesticides/ Seed and At-Planting Insecticide Treatments:

form pit around field and sprinkle Malathion 5% ; Chloropyriphos 1.5%
spray 500 ml dichlorovous 85SL o3 kg of carbaryl 50 WP or 1 lit of Quinalphos 25 EC in 500 lit water per ha.

4. Maize Stem Fly - Atherigona orientalis

These are small grey coloured fly. The larvae are small, pale yellow tappering towards head. It affects the maize plants at the seedling stage and leads to drying of the seedlings or ‘dead heart’.

MANAGEMENT:

Seed treatment with imidacloprid 70 WS 10 g/kg of seeds
Use of safe chemical pesticides/ Seed and At-Planting Insecticide Treatments:

Carbofuran 3%CG 33.3 kg/ha
Dimethoate 30%EC 1155 ml/ha
Phorate 10%CG 10 kg/ha

5. Wireworms- Agriotes Spp.

Wireworms look wiry with conspicuous segments. The adult click beetles have two characteristic rear-facing pointed corners of pronotum. The pests reduce germination rate by feeding on germinating seed , damaging or eliminating a potential plant. Wireworms may also injure corn by feeding on soft stem and root tissues underground.

MANAGEMENT:

Crop rotation including alfa-alfa and high glucosinolate or use of Brassica spp.
Use of trap crops: trap crops used for maize could include wheat.
Use of biopesticides: Release of Trichogramma chilonis at rate of around 1 lakh per hectare and use of fungi like Metarrhizium, Beauveria.
Destruction of pest harbouring places.

Category

Insect Pests and their Management

Wheat Insect Pest

kiran — Wed, 03 Oct 2018 04:30:08 +0000

Wheat Insect Pest kiran Wed, 10/03/2018 - 10:15

1. Pink borer - Sesamia inferens

The larvae are pinkish, smooth cylindrical body about 25mm.The moth is straw colored with stout body. These are nocturnal and lay eggs on leaves or on the ground. Damage in wheat are dead heart in young plants and are killed together, older plants are killed leaving few grains only.

MANAGEMENT:

Removal of plants showing early damage symptoms: removal and destruction of infested plants from the base
Use of Bacillus thuringiensis @3gm/lit.
Use of biopesticides: Release of Trichogramma chilonis at rate of around 5o thousand to 1 lakh per hectare.
Use of safe chemical pesticides/ Seed and At-Planting Insecticide Treatments:

To fields showing greater than 5 % dead heart symptoms, spray with 875 ml Triazophos 40 EC or 1.25-2.5 liters of chloropyriphos 20EC in 500-1000 liter of water.

2. Army worm - Mythimna separate

MANAGEMENT:

Manual operations: handpicking of large caterpillars, beetles and egg masses and use of sweep nets, wire gauges etc.
Use of safe chemical pesticides/ Seed and At-Planting Insecticide Treatments:

form pit around field and sprinkle Malathion 5% ; Chloropyriphos 1.5%
spray 500 ml dichlorovous 85SL @3 kg of carbaryl 50 WP or 1 lit of Quinalphos 25 EC in 500 lit water per ha.

3. Wireworms - Agriotes Spp.

MANAGEMENT:

Crop rotation including alfa-alfa and high glucosinolate or use of Brassica spp.
Use of trap crops: trap crops used for maize could include wheat.
Use of biopesticides: Release of Trichogramma chilonis at rate of around 1 lakh per hectare and use of fungi like Metarrhizium, Beauveria.
Destruction of pest harbouring places.

4. Termites - Odonotermes obesus/Microtermes obesi

These are important pests in wheat. These are delicate white bodies with light brown head around 3-6 mm long. They cause destruction of germinating grains. Hollow main primary root beneath the soil filled with soil, tunnels found along the shoot filled with soil is seen.

MANAGEMENT:

Destruction of pest harbouring places: destroy the stubbles, weed and possible alternate hosts of pests like stem borer through different cultural practices
Locating termitarium for removal
Use of safe chemical pesticides/ Seed and At-Planting Insecticide Treatments:

Seed treatment with Chloropyriphos @6ml/kg of seed.
Soil application of Chloropyriphos 50 EC @10ml/l as a soil drench at sowing time in termite prone soil.
Use Chloropyriphos 10 G @ 1 kg per ropani before sowing in heavily infected area
Us of kerosene as an alternative.

Category

Insect Pests and their Management

Rice Insect Pest

kiran — Wed, 03 Oct 2018 04:29:52 +0000

Rice Insect Pest kiran Wed, 10/03/2018 - 10:14

1. Brown plant hopper - Nilaparavata lugens

Both nymph and adult feed on paddy by sucking cell sap. The nymphs are brownish in color and have grayish blue eyes. They lay eggs in mass by lacerating parenchymatal tissues. The eggs are somewhat cylindrical having two distinct spots.

Damage: Suck the cell sap from the leaves and the leaves turns yellow. A heavy infestation produces symptoms of ‘hopper burn’ i.e leaves become dry and brown after insect feeding and the infected plant often lodges in patches. Even tillering is adversely affected. High humidity, optimum temperature, high nitrogen application and no wind favors growth of BPH.

Management

Maintain proper spacing
Grow resistant varieties IR26, IR36, IR56, IR64, and IR72
Alternate drying and wetting of the field and draining of the standing water.
Spray monocrtophos 35 EC @ 2ml/l (78 ml/ropani) at nursery stage.
Application of granular phorate 10G@ 0.5 kg/ropani or carbofuran 3G@ 1.2kg/ropani insecticides in presence of thin film of water.
Spray imidacloprid 200 SL @ 0.5ml (15 ml/ropani) or thiomethaxm 25WG @ 0.5g (15kg/ropani) or phaslone 35 EC @ 2ml/l (100ml/ ropani) water or quinolphos 5G @ 1.5kg/ropani.

2. Yellow rice stem borer - Scirpophaga incertulas

They are dirty white or greenish yellow having brown head and pronotum. Female moth is bigger than the male and has a centrally situated black spot on each of the forewing also female has prominent tuft or brownish yellow silken hair at the tip of their abdomen. They lay eggs on the underside of the leaves. The eggs are covered with yellowish brown hair of the female tuft.

Damage: causes death of the central leaf whorl at the vegetative stage known as dead heart and at reproductive stage causes ear devoid of grain known as white head.

Management

Larva may be killed by flooding of the field in rainy season.
Before the transplantation clip the tips of the seedlings
Recommended insecticides and doses for spray (Twice at 7-10 days interval)
Monocrotophos 36 WSC @ 1100 ml ha-1 or Chlorpyriphos 20 EC @ 2000 ml ha-1 or Endosulfan 35 EC @ 1100 ml ha-1 or Cartap 50 WP @ 800 g ha-1 or Fipronil 5 SC @ 800 ml ha-1

3. Rice ear-head bug - Leptocorisa oratorius

It is green, light brown or mixed yellow in color. The head is triangular, have long legs. The abdomen of both sexes is constricted slightly in the middle and either side contain stink gland that emit foul odor hence called stink bug or Gandhi bug. Lay round yellow eggs along the midrib on the upper surface of the leaf blade.

Damage: adult and nymph both suck sap of developing rice grain at the milking stage and causes empty or partially filled and chaffy grains and enhances subsequent fungal and bacterial infection.

Management

Using light traps can monitor as well as reduce the insect population
Keep on hanging the cattle urine soaked gunny bags or cow dung wrapped cloth or dead animal body just at the crop height in the field to attract the bug
Tiger beetle are the predator of ear-head bug
Dust any one of the following at 25 kg/ha twice, the first during
- Quinalphos 1.5 D
- Methyl parathion 2% DP
- KKM 10 D (The new KKM dust formulation consists of 10% of Acorus calamus rhizome powder and 90% of flash which is a waste product from Thermal Power Station)
- flowering and second a week later: Spray any one of the following twice as above
  - Neem seed kernel extract 5% 25 kg/ha
  - Notchi or Ipomoea or Prosopis leaf extract 10%
  - Malathion 50 EC 500 ml/ha

4. Rice case worm - Nymphula depunctalis

They lay eggs on the undersurface of the leaves and grasses. The larva makes tubular case out of a portion of the leaf cut from it and remain inside it.

Damage: The larva feeds upon the leaves. The leaf blade are eaten away completely leaving only the midribs. In case of severe attack, the tillers become stunted and lose their vigor and often the plants are killed

Management

Drain off the water from the field to kill the floating larva.
At 10-12 DAS 1 ml of methyl parathion 50EC or 0.5ml fenitrothion 100EC or 0.9ml diazinon 60EC or 1.3ml monocrotophos 36SL or 2ml chloropyriphos 20 EC or 1.5ml fenthoate 50EC or 2ml phasalone 35EC or 2ml endosalfon 35EC or 2ml quinolphos 25EC in 1 liter of water for spraying crop

5. Rice leaf folder - Cnaphalocrosis medinalis

It is greenish caterpillar that feed inside the fold made by fastening together the edges of a leaf. Moths are golden or yellowish brown; the wings have 2-3 wavy lines characterized by dark bands. They lay oval, creamy white egg on the leaves and leaf sheath.

Damage: young larva feed on tender leaves without folding them. The older larvae fasten the longitudinal margins of leaf together with a sticky substance and feed inside the fold by scrapping the green matter. The scrapped leaf become membranous, turn white and finally wither. The heavily infested crop has streaks and appear whitish from a distance. Single larva damages a number of leaves as it migrates from leaf to another as a result of attack photosynthetic activity of leaves is interfered and the plants are exposed to fungal and bacterial infections.

Management

Use light traps to reduce the population
Maintain wider spacing and use low nitrogenous fertilizer
Use Trichogramma chilonis for 6 times @50000-100000 per hectare soon after the appearance of moth.
Spray cartap 50 WP @ 600 g ha-1 or monocrotophos 36 WSC @ 850 ml ha-1or chlorpyriphos 20 EC @ 1500 ml ha-1or quinalphos 25 EC @ 2000 ml ha-1.
Spraying should be done only when there are 3 freshly damaged leaves per hill

6. Rice ear cutting caterpillar - Mythimna separata

This is also known as armyworm of which the adult is pale brown. They lay egg in overlapping rows. The larva larva pupates in clumps of paddy, in cracks and crevices in ground or in loose soil.

Damage: caterpillar cause damage to paddy leaves and ears. Newly hatched larva feeds on the epidermis of the tender leaves. The second and third instar larva feed by cutting the leaves from the edge toward mid rib. The fourth, fifth and sixth instar larvae besides damaging leaves also cut off the panicles mostly at the base.

Management

Collect and destroy the caterpillar
Install light traps
1 ml of methyl parathion 50EC or 0.5ml fenitrothion 100EC or 0.9ml diazinon 60EC or 1.3ml monocrotophos 36SL or 2ml chloropyriphos 20 EC or 1.5ml fenthoate 50EC or 2ml phasalone 35EC or 2ml endosalfon 35EC or 2ml quinolphos 25EC during evening hours.

Category

Insect Pests and their Management