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Crop: Soybean
S.N: Glycine max
Family: Fabaceae
Pests |
Important pests of Soybean
1. Bihar hairy caterpillar: Spilosoma obliqua
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Symptoms of damage
- Young larvae feed gregariously on chlorophyll mostly on the under surface of the leaves, due to which the leaves look like brownish-yellow in colour.
- In later stages the larvae eat the leaves from the margin.
- The leaves of the plant give an appearance of net or web
Identification of the pest
- Eggs: Laid in cluster on the under side of leaves.
- Larva: Covered with long yellowish to black hairs
- Adult: Medium sized brown moth with a red abdomen.
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| Larval scrabbing |
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Management
- Deep summer ploughing.
- Avoid pre monsoon sowing.
- Use optimum seed rate.
- Adequate plant spacing should be provided
- Intercrop soybean either with (early maturing) pigeon pea variety or maize or sorghum in the sequence of 4:2 should be practiced.
- Collect & destroy infested plant parts, egg masses and young larvae.
- Field Sanitation: Remove the infested plant parts at least once in 10 days and bury them in compost pit to monitor and reduce the population.
- Light Trap: Install one light trap (200W mercury vapour lamp) per hectare to catch the adults of some nocturnal pests such as hairy caterpillar (positively phototropic).
- Apply chlorpyriphos 20 EC @ 1.5 lit/ha or trizophos 40 EC @ 0.8 Lit/ha or quinalphos 25 EC @ 1.5 lit/ha.
- Dust Chlorpyriphos 1.5% DP quinalphos 1.5% @ 25kg/ha when the population is likely to reach 10/m row length (ETL). Repeat it as needed.
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2. Gram pod borer: Helicoverpa armigera
Symptoms of damage
- The young larvae feeds on the chlorophyll of young leaves and skeletonize it.
- They feed voraciously on the foliage in early stage, may defoliate the plant and later they feed on flowers and pods.
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Identification of the pest
- Eggs: Spherical in shape and creamy white in colour, laid singly
- Larva: Shows colour variation from greenish to brown. It has dark brown grey lines on the body with lateral white lines and also has dark and pale bands.
- Pupa: Brown in colour, occurs in soil, leaf, pod and crop debris
Adult
- Light pale brownish yellow stout moth.
- Forewings are olive green to pale brown with a dark brown circular spot in the centre.
- Hind wings are pale smoky white with a broad blackish outer margin.
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Management
- Deep summer ploughing
- Install pheromone traps at a distance of 50 m @ 5 traps/ha for each insect pest.
- Erect bird perches @ 50/ha.
- Clip terminal shoots on 100 days of crop growth.
- Setting of light traps (1 light trap/5 acre) to kill moth population
- Dusting with Chlorpyriphos 1.5 % DP or fenvalerate 0.4% or quinolphos 1.5% @ 25 to 30 kg/ha
- Spray with Chlorpyriphos 1.5 % DP @1200 ml/ha or quinolphos 25 EC @ 1.0 lit/ha.
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3. Tobacco caterpillar: Spodoptera litura
Symptoms of damage
- Larvae feed on the chlorophyll of the leaves.
- The eaten leaves give the appearance of whitish yellow web.
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Identification of the pest
- Egg: Egg masses appear golden brown.
- Larva: Pale greenish with dark markings. Gregarious in the early stages
Adult
- Forewings: Brown colour with wavy white marking
- Hind wings: White colour with a brown patch along the margin
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Larva |
Adult |
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Management
- Deep summer ploughing.
- Avoid pre-monsoon sowing.
- Optimum seed rate (70-100 kg/ha) should be used.
- Collect and destroy infested plant parts, egg masses and larva.
- Install sex pheromone trap @ 10 traps/ha for early deduction of the pest.
- Erection of bird perches @ 10-12/ha.
- Field Sanitation: Remove the infested plant parts at least once in 10 days and bury them in compost pit to monitor and reduce the populations of tobacco caterpillar. Traps are used for monitoring the pest situation.
- Install one light trap (200W mercury vapour lamp) per hectare to catch the adults of some nocturnal pests such as tobacco caterpillar (positively phototropic).
- Install five sex pheromone traps per hectare (change septa after 3 weeks), specific for male adults of tobacco caterpillar (separate pheromone for each).
- Apply Profenophos 50 % EC @ 1000 ml/ha or deltarnethrin 2.8 EC @ 750 ml/ha
or quinolphos 25 EC @ 1000ml/ha
- In case of severe infestation apply polytrin 44% @ 1 lit/ha
or profenophos 50 EC 2.00 lit/ha
- Dust Deltamethrin 2.8% EC or quinalphos 1.5% @ 25kg/ha when their population is likely to reach 10/m row length (ETL). Repeat it as needed.
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4. Thrips: Thrips tabaci
Symptoms of damage
- The infected leaf turns whitish-brown in colour.
- In case of heavy infestation the leaves get dry and drop down and slowly the plant becomes leafless.
Management
- Dusting of cow dung ash and spraying of clay suspension as asphyxiants (in small area and low incidence of sucking insects)
- Spray 0.05 % quinalphos 25 EC or monocrotophos 36 WSC, oxydemeton methyl 25 EC, or dimethoate 30 EC @ 2ml /lit at the crop age of 35-40 days and repeat after 15 days if needed.
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5. White fly: Bemisia tabaci
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Symptoms of damage
- Due to attack of the insect the leaves turn yellow and become curled.
- This insect spread the mosaic disease in soybean.
Identification of the pest
- Nymphs and pupae: Black and round or oval. Pupae have marginal bristles.
- Adults: Small, yellow bodied insects with white wings which are densely covered with a waxy powder.
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Management
- Dusting of cow dung ash and spraying of clay suspension as asphyxiants (in small area and low incidence of sucking insects)
- Spray 0.05 % quinalphos 25 EC or monocrotophos 36 WSC, oxydemeton methyl 25 EC, or dimethoate 30 EC @ 2ml /lit at the crop age of 35-40 days and repeat after 15 days if needed.
6. Soybean Aphid: Aphis spp.
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Symptoms of damage
- They suck the plant sap from the stem, leaves and pods which cause reduction in yield.
- The infested leaves are wilted or curled.
- Plant stunting, reduced pod and seed counts, puckering and yellowing of leaves.
Identification of the pest
- Winged adults: Have a black head and thorax.
- Aphids: Excrete honeydew on surface of lower leaves.
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Aphids under surface of leaves |
Management
- Dusting of cow dung ash and spraying of clay suspension as asphyxiants (in small area and low incidence of sucking insects)
- Spray 0.05 % quinalphos 25 EC or monocrotophos 36 WSC, oxydemeton methyl 25 EC, or dimethoate 30 EC @ 2ml /lit at the crop age of 35-40 days and repeat after 15 days if needed
7. Jassids: Apheliona maculosa
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Symptoms of damage
- Infested leaves start yellowing from the margins.
- In case of severe attack, all the leaves become yellow and eventually fall off from the plants.
Identification of the pest
- Adults and nymphs: are light green in colour and suck the sap from leaves and stem.
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Management
- Install one light trap (200W mercury vapour lamp) per hectare to catch the adults of some nocturnal pests such as jassid, (positively phototropic)
- Spray 0.05 % quinalphos 25 EC or monocrotophos 36 WSC, oxydemeton methyl 25 EC, or dimethoate 30 EC @ 2ml /lit at the crop age of 35-40 days and repeat after 15 days if needed.
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II. Stem Borers
8. Girdle beetle: Oberea (Obereopsis) brevis
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Symptoms of damage
- Girdling of stems and petioles
- The inside of the stem is eaten by the larvae and a tunnel is formed inside the stem.
- The leaves of plant of infected portion are unable to get the nutrient and are dried up.
- In later stages the plant is cut at about 15 to 25 cm above the ground.
Identification of the pest
- Larva: White, soft-bodied worm with a dark head.
- Adult: The freshly emerged adult is yellow, red, brown on the head, thorax and bases of elytra.
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Management
- Deep summer ploughing
- Planting time on the onset of monsoon
- Optimum seed rate (70-100 kg/ha) should be used
- Intercropping with maize or sorghum should be avoided
- Crop rotation should be followed
- Avoid excess nitrogenous fertilizers.
- Collect and destroy infested plant parts and egg masses.
- Remove the infested plant parts at least once in 10 days and bury them in compost pit to monitor and reduce the populations of girdle beetle
- Apply phorate 10 G @ 10 kg/ha or carbofuran 3 G @ 30 kg/ha at the time of sowing.
- One or two sprays of 0.03% dimethoate 30 EC or 0.05% quinalphos 25 EC or 0.05% methyl demeton 25 EC or 0.04% monocrotophos 36 SC can check further damage.
- Spray monocrolophos 36 WSC, quinalphos 25 EC triazophos 40 EC @ 2 ml/lit. at the crop age of 30-35 days and repeal after 15-20 days (1000 l spray/ha)
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9.Stem Fly: Melanagromyza sojae
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Symptoms of damage
- The eggs are laid on leaves.
- After hatching from the egg yellowish maggots bore the nearest vein of the leaf.
- The maggot then reach the stem through petiole and bore down the stem.
- If the infected stem is opened by splitting, distinct zig zag reddish tunnel can be seen with maggot or pupae inside it.
- The maggots feed on cortical layers of the stem, may extend to tap root, killing of the plant.
Identification of the pest
- Maggot: White in colour and remains inside the stem.
- Adult: Flies are shining black and about 2 mm long.
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Infested stem with bore holes |
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Management
- Deep summer ploughing.
- Avoid pre monsoon sowing.
- Use optimum seed rate and plant spacing.
- Proper crop rotation with dissimilar crops should be followed.
- Remove and destroy the damaged plant parts.
- Spray monocrotophos 36 WSC @ 1 l/ha, twice, at the crop age of one and three weeks. In case of severe infestation, apply phorate or lindane in the soil @ 10 kg/ha before sowing.
- Soil application of phorate 10 G @ 10 kg/ha or carbofuran 3 G @ 30 kg/ha at the time of sowing will prevent early infestation by stem fly.
- One or two sprays of 0.03% dimethoate 30 EC or 0.05% quinalphos 25 EC can stop the damage.
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