IMPORTANT PESTS AND DISEASES OF CHILLI

Chillithrips: Scirtothrips dorsalis Symptoms of damage:

• The infested leaves develop crinkles and curl upwards

• Elongated petiole

• Buds become brittle and drop down

• Early stage, infestation leads to stunted growth and flower production, fruit set are arrested

Identification of pest:

• Nymph: Are small, linear, easily fragile abdomen with straw yellow colour

• Adult: Fringed wings

Tobacco cutworm: Spodopteralitura

Symptoms of damage:

• Newly hatched larvae scrap the green matter in the leaf

• Affected leaf looks like a papery white structure

• Later instar larvae feed by making small holes

• In severe infestations they feed voraciously on the entire lamina and petiole

Identification of pest:

• Egg: Eggs are golden yellow, laid in masses and covered by silky hairs.

• Larva: Are seen in groups, young caterpillars are light green with black head or black spots

• Adult: Are brown in colour. Forewings are brown colour with wavy white markings, hind wings are white colour with a brown patch along the margin.

Management:

• Plough the soil to expose and kill pupae

• Castor as a trap crop

• Set up pheromone trap @15/ha

• Collect and destroy the egg masses, gregarious larvae and grown up caterpillars

• Spray any one of the following insecticides

Fruit Rot and Die Back: Colletotrichumcapsici

Symptoms

• As the fungus causes necrosis of tender twigs from the tip backwards the disease is called die-back Infection usually begins when the crop is in flower. Flowers drop and dry up.

• There is profuse shedding of flowers. The flower stalk shrivel and dry up. This drying up spreads from the flower stalks to the stem and subsequently causes die-back of the branches and stem and the branches wither. Partially affected plants bear fruits which are few and of low quality.

• On the surface of the soil the necrotic areas are found separated from the healthy area by a dark brown to black band.

Management

• Use of disease-free seeds is important in preventing the disease. Seed treatment with Thiram or Captan 4g/kg is found to be -effective in eliminating the seed-borne inoculum.

• Good control of the disease has been reported by three sprayings with Ziram O.25% Captan 0.2% or miltox 0.2%. Chemicals like wettablesulphur 0.2%, copper oxychloride 0.25% and Zineb 0.15% not only reduced the disease incidence but also increased the yield of fruits.

• The first spraying should be given just before flowering and the second at the time of fruit formation.

• Third spraying may be given a fortnight after second spraying.

Viral diseases

Leaf curl

• Leaves curl towards midrib and become deformed.

• Stunted plant growth due to shortened internodes and leaves greatly reduced in size.

• Flower buds abcise before attaining full size and anthers do not contain pollen grains.

• The virus is generally transmitted by whitefly. So control measures of whitefly in this regard would be helpful.

Mosaic Viruses

• Light green and dark green patches on the leaves.

• Stunted plant growth during early stages.

• Yellowing, chlorotic ring spots on leaves and fruits.

Management of viral diseases

• Control measures are not known for majority of viral diseases.

• Hence, mechanical, cultural methods are mostly recommended.

• The infected plants should be uprooted and burnt or buried to avoid further infection.

• Avoid monoculture of chilli crop.

• Selection of healthy and disease - free seed.

• Suitable insecticidal sprays reduce the incidence of viral diseases, since majority of viral diseases are transmitted by insect vectors.

• Apply Carbofuran 3G @ 4-5 Kg/acre in the mainfield to control sucking complex and insect vectors selectively.

• If it is not possible spray the crop with systemic insecticides. Dimethoate 2ml of Acephate 1g per litre of water.

• Collect and destroy infected virus plants as soon as they are noticed.