By:- Amarjit Singh, Ravinder Singh Chandi and Anureet Kaur Chandi
Chilli and capsicum are one of the popular and remunerative vegetable crops grown in India. Chilli is grown in open field conditions and capsicum is grown in open as well as under protected conditions. These crops are attacked by various insect pests and diseases causing huge qualitative and yield losses. Pests and diseases reduce the quality of produce as even a small spot on the fruit will considerably reduce its market value. As the capsicum crop is having relatively longer duration in polyhouse, the plant is more exposed to adversities of insect pests and diseases. Hence identification of various insect pests and disease symptoms and their management strategies at right stage of the crop should be deployed so that crop is saved from the damage. Various pests viz. aphid, thrips, whitefly, mites and fruit borer and diseases like die back & fruit rot, wet rot, leaf curl and mosaic cause damage to the crop.
The nymphs of thrips resemble the adults in shape and colour but are wingless and smaller in size. Nymphs and adults cause damage by sucking cell sap from tender regions and causing shrivelling of leaves. The attacked plants remain stunted and dry up and severe infestation causes malformation of leaves, buds and fruits. Nymphs and adults lacerate the plant tissues and suck the sap from the leaves forming white blotches and curly leaves with a stunted plant look. Thrips cause upward curling of leaves and reduce leaf and plant growth. In severe case, the leaves of attack plant become wrinkled and gradually dry up. Consequently, yield is reduced considerably.
A. Remove weeds in and around the field, which serve as host of thrips.
B. Protect the nursery beds from thrips attack.
C. Avoid excessive nitrogen fertilizer application.
D. Avoid overuse of insecticides to preserve populations of beneficial insects.
E. Spray the crop with Regent 5SC (fipronil) @ 250 ml/acre in 100 litres of water
Damage by this pest is caused in two ways: a) the vitality of the plant is lowered through the loss of cellsap, and(b)it acts as a vector of leaf curl virus. Consequently, the growth of the plant is adversely affected and when the attack appears late in the season, the yield is lowered considerably.
l. Protect the crop in the nursery beds from whitefly by covering with a nylon net or by spraying with recommended insecticides.
ll. Regular monitoring of the crop should be done to check for whitefly infestation.
lll. Regular surveillance on alternate host crops should be carried out for timely management of whitefly.
lV. Eradication of weeds growing on field bunds, waste lands, road side and irrigation channels/canals to avoid further spread of whitefly to okra fields.
V. For its management, spray the crop with Daita 10EC (pyriproxyfen) @ 160 ml/acre in 100 litres of water.
Aphids may appear on the underside of the leaves, flowers or inflorescences and young sprouts as a colony. Nymphs and adults suck the cell sap, thereby causing stress on the plant and lowering its vitality. In the case of a severe attack, aphids can cause severe damage to the plant. Aphids excrete honeydew on the plant on which sooty mould develops resulting in the blackening of the leaves and thereby reducing the photosynthetic rate of plant. The yield is reduced directly and indirectly through the spread of virus diseases as the aphids act as vectors.
l. Growers should start monitoring the crop for aphids infestation when the plants are small.
ll. Protect the crop in the nursery beds from aphids by covering with nylon net or by spraying with insecticides.
lll. Area-wide eradication and/or treatment of host plants reduce aphid population.
lV. Eradicate weeds growing on field bunds, waste lands, road side and irrigation channels/canals as they contribute to aphid problem.
V. Conserve natural enemies of aphids in chilli and capsicum.
Vl. Aphid populations tend to be higher in plants that are fertilized liberally with nitrogen.
Vll. Spray the crop with Regent 5SC (fipronil) @ 250 ml/acre or Daita 10EC (pyriproxyfen) @ 160 ml/acre in 100 litres of water
Both adults and nymphs suck sap from the leaves resulting in the leaves curling downwards. In severe infestation, scarring of the stem and fruit skin is also common. Frequent watering of plants during the dry weather helps to reduce the pest population.
l. Spray 5% neem fruit aqueous extract or 200 ml Omite 57 EC (propargite) or 100 ml Obreron 22.9 SC (spiromesifen) per acre in 100 litres of water
ll. For the preparation of neem fruit aqueous extract, take fresh neem fruits, dry in shade and make a course powder by grinding. Mix 5 kg of fruit extract powder in 100 litres of water and keep it for 12 hours. Filter the material in a muslin cloth and spray it.
lll. Keep waiting period of 7 days after spray of acaricides.
This pest is gaining importance in North India and emerged as an important pest of chilli crop. It damages the crop at flowering and fruit formation stage. Severe attack of fruit borers leads to flower and fruit drop in chilli. This pest bore into the tender and maturing fruitsand feed on the seed resulting in the hallowing of the fruit and finally dropping of the infested fruit.
l. Pick regularly all ripe fruits before spraying.
ll. All the infested fruits should be picked and destroyed.
lll. Spray 50 ml Coragen 18.5 SC (chlorantraniliprole) or 50 ml Tracer 45 SC (spinosad) or Regent 5SC (fipronil) @ 250 ml/acre in 100 litres of water per acre.
lV. Same insecticide should not be used repeatedly in order to avoid the development of pesticide resistance.
This is an important disease of chilli and is severe during the rainy season in July- August. The fruit rot phase of the disease can cause heavy damage in the field and also during transit. Fruit rot symptoms mainly appear on mature red fruits as circular to elliptical sunken spots with black margins. Numerous black dots (fructifications of the fungus) appear on the spots in concentric rings. The diseased fruits often fall prematurely. The fungus also causes necrosis of the tender twigs from the tip backwards after the fruits begin to ripen. The entire top of the plant may be killed. Large numbers of black dots are formed on the affected twigs. To get rid of this problem it is desirable to obtain seed from healthy fruits and thereafter treat the seed with Captan@ 2g per kg before sowing. Check the disease in the field by spraying the crop with Folicur @250 ml or Indofil M-45 or Blitox @750g in 250 litres of water per acre. Give the first spray in the first week of July followed by three more sprays at 10 days intervals.
This disease is severe during the months of July and August. The pathogen attacks tender young shots, flowers and green fruits. The infected parts get rotten and the growth of the fungus is visible as black pinheads on the infected parts. The infection spreads downward and the infected portion becomes lumpy. Green fruits become soft with bead-like black conidial heads. The disease is favoured by warm and humid weather conditions after heavy rains. Manage this disease by adopting control measures as recommended for fruit rot and dieback of chilli.
This is a very common viral disease of chilli. The characteristic symptoms of the disease are the downward curling of the leaves and their small size. Affected plants become stunted and give a bushy appearance. Fruiting is very rare and if formed the fruits are smaller and deformed. Such plants remain stunted in growth and give a rosette appearance due to the proliferation of axillary buds. The size of these leaves is also reduced. The affected plants bear fewer fruits which may be small and deformed. This disease is transmitted by whitefly. To get good returns from the crop it is necessary for the growers to manage this disease right from nursery. The nursery should be raised under poly-house and infected plants should be removed. The population of whitefly should be controlled by spraying with Daita 10EC (pyriproxyfen) @ 160 ml/acre in 100 litres of water. Virus-infected plants should be rogued out and destroyed as soon as they become visible.
The leaves of the plants show mottling and have yellow and dark green patches on the leaf lamina. These plants remain stunted in growth. Plants exhibiting disease symptoms should be rogued out of the field and destroyed. This disease spreads through aphids as well as through contact. Therefore, unnecessary touching of the plants should be avoided and after touching infected plants, farmers should wash their hands and then touch the healthy crop. The crop should be protected from insect vectors by spraying with Regent 5SC (fipronil) @ 250 ml/acre or Daita 10EC (pyriproxyfen) @ 160 ml/acre in 100 litres of water. To get maximum returns from chilli cultivation, the growers are also advised to raise hybrid seeds of chilli from disease free parents. The virus free hybrid seeds will ensure healthy and disease free nursery plants. Thus the seeds should be harvested only from virus free plants.
Fruit rot of chilli Leaf curl of chilliChilli mosaic virus
Thrips Whitefly Fruit borer Aphid
The Writers are from the Department of Plant Pathology and the Department of Entomology
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29 Jan, 2024
29 Jan, 2024
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