Learn about how to control pests of oilseed crops!
1. Castor Semilooper:
Achaea Janata Linn. (Lepidoptera- Noctuidae):
This is one of the most destructive pests of castor crop. Damage is caused by the caterpillars which feed voraciously on the delicate parts of the leaves and at the end only the veins remain. Due to considerable loss of leaves, the castor seed yield is also greatly reduced.
The peculiarity of Achaea janata is that in the larval stage, it is a serious pest of castor and in adult stage it is a fruit sucking moth and is a serious pest of Citrus fruits, a rare feature among moths, which are normally harmless.
The adult of Achaea janata is a pale reddish-brown moth with a wing expanse 60-70 mm. The wings, both the fore and the hind are decorated with broad zigzag markings and a large yellowish area and dark brown patches. The mature larva is dark and is marked with blue black, yellow and reddish stripes and a dorsal hump near the head end of the body. There is a characteristic white mark on the head. The colour pattern is very different in this insect and some workers recognize four different varieties of caterpillars in the 3rd and 4th instars. They are very distinct against the background of the plants.
Each female moth can lay several hundred eggs. The total number of eggs laid by a female varies from 450-500 which are deposited singly on the leaves. The egg is about 1 mm. in length and has numerous ridges and furrows on the surface, radiating from a circular depression at the apex. On account of its cryptic blue-green colour, it is extremely difficult to spot out the eggs on the leaves.
Hatching of the larva takes place within 2 to 5 days. The first instar larva is extremely small and measures about 3.5 mm. in length. The larva emerges by biting a hole into the egg shell; the latter also forms the first meal of the newly hatched larva before it begins to feed on the leaves. The larva feeds and moults 4 or 5 times and become full grown in about 15-25 days.
The mature larva measures about 60 to 65 mm. in length. The larva after searching a suitable hiding place prepares a loosely knitted cocoon of silk. Occasionally soil particles also get attached with the cocoons. The pupal duration is about 10-15 days and the moth, on emergence feeds on soft fruits of citrus, mango etc. There may be several generations in a year.
Semiloopers can be controlled by spraying Thiodan (endosulfan) 35 EC @ 1.25 litres in 800 litres of water/ha. The use of insecticides is not recommended in the case of castor crop meant for the rearing of the erisilkworms. The semiloopers should be regularly collected and destroyed.
2. Castor Hairy Caterpillar:
Euproctis Lunata Walk. (Lepidoptera- Noctuidae):
The castor hairy caterpillar is distributed throughout India. The caterpillar feeds on the leaves of various host plants and in the case of severe infestation they may cause complete defoliation. The attacked plants remain dwarf (under developed) and produce very little seed. Thus it is the larvae which cause damage to the castor plants.
Life History:
The eggs are laid in the late winter i.e. February in clusters on the underside of the leaves. The eggs are covered with brown hairs from the anal tuft of the female. They hatch in 5-7 days. The young larvae feed gregariously for about a week and then disperse and feed individually. They pass through 6 stages and are full-fed in 2-3 weeks. The mature larvae measure 35-40 mm. dark grey in colour with a white stripe on the dorsal side. They have long hair all over the body.
They make loose silken cocoons in the plant debris lying on the ground and pupate inside. The pupal stage lasts about a week in summer. During the winter months the egg, larval and pupal stages may be prolonged. The moths are pale yellow and are seen sitting on castor and other neighbouring plants during day-time and are harmless.
The young caterpillars can be killed by applying 5% malathion or carbaryl dust to the crop. The grown up caterpillars can be killed with methyl parathion 0.04% sprays.
3. Castor Capsule Borer:
Dichocrocis Punctiferalis Guen. (Lepidoptera- Pyralididae):
The castor capsule borer is distributed throughout the country. The damage is caused by the caterpillars which bore into the capsules. The mature caterpillar measures 25-30 mm. in length and is reddish- brown in colour with black blotches all over the body and a pale stripe on the lateral side, the moths are orange yellow with black markings on both the wings. Since the capsules and the seeds are damaged from inside, the yield is greatly reduced.
The moths lay eggs on the leaves and other soft parts of the plant. The eggs hatch in about a week. The larvae pass through 4-5 instars and are full fed in 2-3 weeks. Pupation takes place inside the seed or in the frass that collects after feeding. The pupal stage lasts about one week. The life cycle is completed in 4-5 weeks. Three generations are completed in one year. This pest is active on caster from September to March.
Control:
The castor capsule borer can be controlled with the repeated applications of carbaryl 0.2%. In the capsule bearing crop application of insecticides is very difficult. It has been advised to collect and destroy the infested shoots and capsules.
4. Mustard Sawfly:
Athalia Proxima Klug (Hymenoptera- Tenthredinidae):
It feeds on various cruciferous plants like mustard, cabbage, cauliflower, turnip, radish etc. Damage is done by the larvae which are dark green, measuring about 16-18 mm. in length. It is a very harmful pest of mustard and other crops of the family Cruciferae.
The pest is distributed practically throughout the India. The activity is confined from October to March. It is in the larval stage that the pest damages the crop by voraciously feeding on the leaves of the young crop. The adult stage is a rather thick-set insect with a mixture of yellow-brown markings on the body and a dark reddish-brown colour on the wings.
Life History:
The female lays 30-35 eggs singly in slits made with the saw like ovipositor along the leaf margins on the underside. The eggs hatch in about 4-8 days and the larvae feed exposed in groups of 3-6 on the leaves during the morning and the evening. They pass through seven stages and are fully grown in 16-35 days. The full grown larva measures 16-18 mm. in length which enters the soil and pupate there in a water proof, oval silken cocoon, and emerges as adult in about 11- 37 days. Thus the life cycle is completed in about 31-74 days.
Control:
Spray the crop with metasystox 25 EC @1 litre/ha or dimethoate (Rogor) @1 litre/ha in 1000 litres of water or malathion 50 EC or thiodan 35 EC @1-1.25 litres/ha in 1000 litres of water.
5. Mustard Aphid:
Lipaphis Erysimi Kalt. (Homoptera- Aphididae):
The most serious pest of the mustard crop is the aphid, L. erysimi. This species has a wide distribution in the world. Besides brassicas to which the mustard belongs, this pest attacks a number of other economic plants, particularly to those of the family Cruciferae. The attack commences on plants even when they are in seed-beds as well as at all subsequent stages of their growth.
They suck the sap of the plant by thrusting their needle like stylets into the tissues. Such damage renders the attacked crop pale, weak, exhausted and incapable of bearing any seed. Leaves are most susceptible, those which are affected curl, shrivel and form cups, and finally drop.
The insect pours a good deal of sugary excreta known as honey dew which makes the infected plant sticky to touch and facilitate the growth of a black fungus on them. This gives the appearance of dirty black leaves with shrivelled up lamina on the plant.
The adult insects are very small having light green or slightly yellowish colour. They have a soft body and are of oblong in shape. One of the special morphological features in these insects is the presence of a pair of short tubes known as honey tubes or cornicles which project from the upper surface of the hind end of the body. It is through these tubes that honey dew is excreted out.
This insect is most abundant in winter i.e. from December to March. In the summer aphids survive on some other cruciferous plants of minor importance. The aphid breeds parthenogenetically and the females give birth to 26-133 nymphs. They grow very fast and mature in 7-10 days. Thereafter, they begin to give birth to another generation. There are about 45 generations in one year. Cloudy and cold weather is very favourable for the multiplication of this pest. Generally, apterous forms are present but during migration of the insect species in spring, winged forms are produced.
Mustard aphid can be controlled by spraying the crop with any one of these insecticides- nicotine sulphate 0.05% diazinon/ methylparathion/phosphamidon 0.025%, dimethoate 0.03%, methyl demeton or malathion 0.1% or 0.04% monocrotophos 40 EC. Basal application of thimet 10% granules @ 10 kg/ha is also useful.
In the flowering season, spraying should be carried out in the evening, when most of the pollinators including honey bees stop visiting the crop. When the crop is in the flowering stage, phosphamidon and dimethoate which are comparatively safer to pollinators, should be preferred.
6. Painted Bug:
Bagrada Cruciferarum Kirk. (Heteropterar Pentatomidae):
It is a serious pest of many of the cruciferous plants as well as those of the cucurbitaceous species, the seriousness being sporadic. All the stages in the insect’s life cycle cause damage to the plants. The individuals suck the sap from the leaves which consequently turn yellow and drop off exposing the plant to bacterial and fungal infection.
The adult is black in colour painted with irregular red markings. The scutellum is very large. The adults are extremely tenaceous and can withstand the absence of food for a fairly long period.
Life History:
The female lays about 230 eggs singly or in groups of 2-12 on the leaves and stems. The eggs which gradually become red in colour hatch in about a weeks’ time into young greenish red nymphs. They immediately start feeding on the plant and gradually change colour. At the same time they moult also, the number of moults varying often. The nymph transform into adult in about 3 weeks’ time. The activity of pest ranges from October to March with 6-7 broods in a year.
Control:
The pest can be controlled by spraying the crop with any of the insecticides- viz. diazinon 0.02% or malathion 0.05% or dimethoate 0.03%.
7. Groundnut Aphid:
Aphis Craccivora Koch. (Homoptera- Aphididae):
It is a serious pest of ground nut and is distributed throughout India. Both nymphs and adults suck the sap from the underside of leaves. The attack at the time of flowering and pod formation reduces the yield considerably. The infestation by this aphid on the ground nut crop usually occurs 4-6 weeks after sowing.
Life History:
The offsprings of the winged forms may be wingless or even parthenogenetic. The female may produce 8 to 30 young ones in a life span of 10-12 days. The young nymphs are brownish in colour and pass through 4 moults to become adult in about 5-8 days. The wingless females start producing the brood within 24 hours of attaining that stage. Breeding occurs – throughout the year and both forms, winged and wingless are present.
Control:
The pest can be controlled by repeatedly spraying the crop with any of the insecticides viz. malathion 0.05%, carbaryl 0.1%, endosulfan 0.05%, dimethoate 0.05%, or methyl demeton 0.05%.
8. Groundnut Leaf Miner:
Stomopteryx Nerteria Meyr. (Lepidoptera- Gelechiidae):
This pest is fairly specific to ground nut, although it has been reported infesting a number of other plants also in different parts of the country. The damage is caused by the small caterpillars which mine into the leaves, skeletonize them and web them together.
Life History:
The adult stage is a small moth rather bronzy in colour and with a wing span of less than 1 cm. Its activities are nocturnal, it is strongly attracted to light, during the day it remains hiding under clods or in crevices. It lays eggs singly on the underside of the leaves of its food plants and one female can lay up to several hundred eggs. The eggs hatch after about 3 days.
The newly hatched larva is about 1.5 mm. It wanders about for a little while and then it mines into the leaves and later on bites its way out. It then webs together a number of leaflets and feed inside the chamber so formed.
The larvae are full grown in 9-17 days. The full grown larva is 6 to 8 mm. in length and dirty-green in colour. Pupation takes place in silken cocoon, which is about 9 mm. in length. Pupal period is about 4 days. Under suitable conditions (food, climate etc.), this insect can breed throughout the year.
Control:
It can be controlled by spraying the crop with carbaryl 0.2%. The pest can also be controlled by spraying the crop with metasystox 25 EC or dimethoate (Rogor) 30 EC @ 1 litre/ha in 1000 litres of water or 250 ml/ha of dimecron in 1000 litres of water.
9. Til Hawk Moth:
Acherontia Styx West. (Lepidoptera- Sphingidae):
This insect is commonly referred as “Hawk Moth” “Sphinx Moth” or “Death’s Head Moth”. The larvae feed on the leaves and defoliate the Til plants (Sesamum indicum). Besides Til, it has also been found to damage potato, brinjal, lab-lab and the ornamental plants like balsam. The moth is also harmful to apiarists because it sucks honey from the honey-combs, although at times it is stung to death by the bees.
The adult of Acherontia styx is a large reddish – brown moth, with a wing span of at times more than 10 cm. The forewings possess a mixture of dark- brown and grey ornamentation with dark blackish- wavy markings and a prominent yellow spot on each wing. The hind wings have an ochre background on which there are two broad dark brown wavy cross stripes. The head and thorax are also dark brown and on the latter there is a prominent Death’s Head mark. The abdomen is ochracious in general hue with dark-brown cross stripes.
Life History:
The moths lay eggs singly on the under surface of the leaves of the food plant and the eggs are fairly large, their colour is at first greenish white but later on it turns yellow. Hatching takes place within a few days and the just hatched larva is pale- yellowish in colour. Soon it begins to feed on the leaves and develops broad green stripes running obliquely along the dorso-lateral surface.
The full grown caterpillars which attain a length upto 5 cm. or more and also a thickness of more than 1 cm. are in the habit of retracting and drawing in the head and some of the anterior segments of the body into a sort of Sphinx- like posture, this along with a horn-like projection from the hinder end of the abdomen enhances the monstrosity of these larvae which otherwise have quite a plump body with a pleasant mixture of soft colours.
The larval period is un-usually long and at times it lasts 2 months or more. The pupa is also almost equally long lived. The winter is passed in the pupal stage in the soil. There are 3 generation in a year.
Control:
The Hawk moth larvae can be controlled by spraying the crop with endosulfan @ 1.25 litres/ha in 1000 litres of water or quinalphos 25EC @ 500 ml/ha in 1000 litres of water. Hand picking is also a good method to suppress the larvae.
10. Til Leaf and Pod Caterpillar:
Antigastra Catalaunalis Dupon. (Lepidoptera- Pyralididae):
This is a serious pest of Til (Sesamum indicum). The larval stage damages both the young apical shoot and the young pods. The adult stage is a medium sized moth with a wing span of 15-20 cm. The fore wings are reddish yellow in colour with zigzag indistinct reddish decorative markings on them the hind wings are pale-yellow and transparent. They are nocturnal in habit.
Life History:
The female moth lays about 140 eggs singly on the underside of the leaves and on the apical portion of the growing shoots. The eggs are greenish in colour and they hatch out within 2 to 7 days depending on the season. The just hatched larva is about 2 mm. in length and somewhat whitish in colour. Later on, the colour changes to green and the mature larva is about 15 mm. in length, is also provided with dark brown markings.
Larval period lasts from 10 days to more than a month. Pupation takes place in cracks, crevices or under the fallen leaves. The just formed pupa is green but becomes brown later on. Pupal period varies from 4 to 20 days. Thereafter the moth emerges which begins to lay eggs for the next generation within 4-5 days after emergence. The pest completes about 14 generations in a year depending on the temperature and humidity.
Control:
The pest can be controlled by spraying the infested crop with carbaryl 0.1% against the moth to prevent them egg laying. Mechanical and physical methods can be also used. For controlling almost all the insect pests of oil seed crops like aphids, leaf miners, thrips and bugs, spraying the crop either with methyl demeton 25 EC @ 1 ml/litre of water or dimecron 100 EC @ 1 ml/ha in 1000 litres of water or dimethoate 30EC @ 1 litre/ha in 1000 litres of water is recommended. Spraying should be repeated if needed.