Soya

Insect Management

Introduction Stem fly Thrips Whitefly Blue Beetle Girdle Beetle Green Jassids Green Semilooper Tobacco Caterpillar Leaf Miner

Introduction

  • Soybean being luxuriant crop, having lush green, soft, succulent and nutritive dense foliage is attacked by over 273 types of insects. Out of the whole range, however, only about two dozens of insects are of significant importance.

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Stem fly

    • This is major pest of soybean in all the soybean growing areas in India as well as in world.
    • During Kharif it is found to infest 95-100% plants and during rabi upto 60%. It remains active from sowing (June-July) to harvesting (October).

Symptoms of damage

  • The adult flies are shining black and about 2 mm long. The damaging stage is maggot which is white in colour and remains inside the stem.
  • Female adults lay eggs inside the cotyledon or leaves. After hatching from eggs, the maggots mine through the leaf and reach the petiole. From petiole, they enter the branch and stem, and feed on xylum and phloem. This results in nonavailability of food material to the plants. When the plants are attacked in early stage, the upper half of the leaves show sign of gradual wit hering.
  • When grown up plants are attacked, they do not show any external symptoms of damage except the exit holes made by the maggots for emergence of adults. Infestation due to stem flies reduce the grain yield by 16 to 20%. With proper control measures atleast 12% yield loss can be avoided.

Control Measures

  • 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 0.07% Endosulfan 35 EC or 0.03% Dimethoate 30 EC or 0.05% Quinalphos 25 EC can stop the damage..

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Thrips

  • They attack soybean from August to October during kharif and from February to April during rabi. Long, hot and humid atmosphere during karif season is found to be more congenial for their multiplication.
  • Adults are minute, yellowish brown in colour with feeble wings.
  • Nymphs are pale yellow.

Nature of Damage

  • Both nymphs and adults scratch the leaf surface and lick the sap coming out of the scratches. This results into brownish spots the leaves.

Control measures

  • Spray 0.01% Endosulphan 35 EC or 0.05 Quinalphos 25 EC or 0.01% malathion.
  • Conclusion: In India soybean crop mainly grown in kharif season. In last few years area under soybean cultivation has increased tremendously. In India around 50 varieties of soybean is grain but none of them are hybrid. By using proper Agro techniques and management practices this crop has potential to became a important oil seed crop.

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Whitefly

  • Though this pest appears regularly on soybean from July to October in Madhya Pradesh, it does not cause economic damage.
  • Adults are small, yellow bodied insects with white wings which are densely covered with a waxy powder. Nymphs and pupae are black and round or oval. Pupae have marginal bristles.

Nature of Damages:

  • Both adults and nymphs suck the plant sap from tender leaves and stem, and transmit YMV disease. Plants suffering from this disease have reduced pod formation and yield. It is reported that if infection occurs when plants are 30 days old, reduction in yield is upto 19% compared to healthy plants.

Control measures:

  • Spray 0.01% endosulphan 35 EC or 0.05 quinalphos 25 EC or 0.01% malathion.

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Blue Beetle

  • This is a new pest of soybean, first reported to feed on soybean from M.P. during kharif

Nature of Damages

  • It appears at seedling stage (June-July) and feeds on cotyledons unifoliates and young trifoliates by making holes on the leaves.
  • Adults are dark shining deep blue with yellowish brown head.

Control measures

  • Spray 0.01% endosulphan 35 EC or 0.05 quinalphos 25 EC or 0.01% malathion.

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Girdle Beetle

    • This is more common in M.P, Rajasthan and West Bengal. Its first occurrence was seen in M.P.
    • It has become more and more devastating insect through years.
    • Infesting 60 to 80% Soybean in recent years.

    Symptoms of damage

    • The initial damage is caused by the female which makes two parallel girdles with its mandibles either on petiole, branch or main stem, for egg laying. These girdles reduce the water supply and thus ensure successful hatching. A female can make 4-6 pairs of girdles on a single plant; eventually the entire portion above the girdles dries. This insect remains active from July to October damaging most severely during August-September.
    • The grubs after hatching from eggs, move downwards by tunnelling the petiole or branch or the stem as the case may be, finally reaching upto the ground level. It has been found that about 75% of the plants get totally damaged when the insect attacks 15-17 days old crop. When the crop is attacked between one and a half to two months age, the plants will appear healthy from outside, but there may be a reduction upto 53% in pod number, 65.5% in pod weight, 56.5% in grain number and 66.6^ in grain weight. This loss is further increased when the grubs cut the stem of maturing plants from 5 to 25 cms above the ground level causing a net loss of 5.43 kg of grains for every per cent of infestation. In general, if 25% of the total plant population is infested by girdle beetle, an inevitable loss of about 136 kg/ha is observed. Early sowing is more prone to attack.
    • The grubs of this insect which tend to fail to complete their development within the same season, enter into diapause during winter. The grubs cut small portion of the stem and crawl along with it by remaining inside and closing one end of it. Finding a suitable place in the crevices they close the other end also and remain till the onset of monsoon (July) when the grubs develop into pupae from which adults emerge out in 8-11 days and again start infesting the crop.

    Control Measures

    • Mechanical removal of dried (infested) leaves can reduce the population of eggs and grubs of girdle beetle and grow resistent varieties.
    • 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 girdle beetle and stem fly.
    • One or two sprays of 0.07% Endosulfan 35 EC or 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. These insecticides have been reported to have detrimental effect on eggs and newly hatched grubs of girdle beetle reducing 90% of their population.

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Green Jassids

  • This is a minor pest of soybean found from August to October in kharif and from February to April in rabi.

Nature of Damage:

  • Adults and nymphs are light green in colour and suck the sap from leaves and stem. Infested leaves start yellowing from the margins. In case of severe attack, all the leaves become yellow and eventually fall off the plants.

Control measures :

  • Spray 0.01% Endosulphan 35 EC or 0.05 Quinalphos 25 EC or 0.01% Malathion.

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Green Semilooper

(Diachrysia orichaicea Fabr)

  • During kharif season, it damages the crop from August to September and during rabi from March to May.





  • Adults are medium sized moths having golden triangular mark on the forewings. Caterpillars of both species are green in colour and from a loop while in motion. With posterior end wider than the anterior end and two white longitudinal markings on the body

Nature of Damage

  • Caterpillars first feed on leaves by scratching the green matter. Later on, grown up larvae consume entire leaf leaving behind only the midribs and veins. When not controlled, the infestation can result into 30% undeveloped pods and about 50% yield loss. In case of heavy attack, the caterpillars are also found to feed on flowers and pods. The caterpillars of this insect are found to suffer from a fungal disease.

Control measures

  • Spray 0.01% endosulphan 35 EC or 0.05 quinalphos 25 EC or 0.01% malathion.

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Tobacco Caterpillar

    • This is a serious and regular pest in M.P. It damages Soybean from mid August to October in karif and from November to March in rabi.
    • Adults are active during night time and remain on the lower leaf surface or on the ground during day time. Forewings are brown in colour with white markings on the centre, and hind wings are membranous white with brown border. Full grown caterpillars are dull green coloured with longitudinal yellow and green lines on the dorsal side and black dots on the first to last abdominal segments.

    Nature of Damages:

    • Newly hatched larvae have characteristic gregarious feeding behaviour. They feed only on the chlorophyll leaving behind the white thin papery leaves. Later instars gradually disperse and feed on the leaves eating away the entire portion. After eating the leaves, they also start feeding on young pods, consequently damaging 30-50% of the pods. It has been observed that soybean crop with higher dose of nitrogen are more prone to attack.

    Control measures:

    • Spray 0.01% endosulphan 35 EC or 0.05 quinalphos 25 EC or 0.01% malathion.

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Leaf Miner

  • Basically this is regular and serious pest of groundnut in Maharashtra, Gujrat and Karnataka, but of late it has started infesting soybean also specially in M.P. and Maharashtra.
  • Adults are small, dark brown moths with two white specks near the costal margin of the forewings. Outer edge of hind wings bear closely placed hairs. Larvae are small, green in colour and with black head.
  • It remains active from June to October during kharif and from November to April during rabi, but maximum damage is observed during third week of September.

Nature of Damages:

  • Newly hatched larvae mine into the leaves and feed between the epidermis. One leaf may contain 2-4 mines, Later on the larvae stick the adjacent leaves together and feed by remaining inside the folded cup-shaped structure. One account of heavy infestation, plant growth retards, pod number reduces and grains become shrivelled, consequently yield losses up to 50% may occur.

Control measures:

  • Spray 0.01% endosulphan 35 EC or 0.05 quinalphos 25 EC or 0.01% malathion.

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Andhra Pradesh

Soya

Soya Management