Chilli (Capsicum annuum) is one of the important vegetable and commercial spice crops grown throughout the tropics and warm temperate regions of the world.
Although there is a scope to enhance the productivity of chilli, a number of limiting factors have been attributed for the low productivity, among which, the damage caused by insect pests and mites is of paramount importance.
More than 293 insects and mite species attack the crop in field as well as storage. Amongst these, the thrips, Scirtothrips dorsalis and yellow mite, Polyphagotarsonemus latus are the most important.
Thrips and mites have become regular pests of the crop in traditional chilli growing tracts, known for monocropping resulting in the qualitative and quantitative crop loss.
The indiscriminate use of insecticides has led to insecticide resistance, pest resurgence, environmental pollution besides upsetting the natural ecosystem. Further the presence of pesticide residues in chillies is a major non tariff barrier against export .
Chilli thrips and mites, characterised by relatively short life cycles, can complete several generations on a crop. Adults and nymphs of these pests suck sap from the leaves and growing shoots. Affected leaves curl upwards and downwards resulting in damage called chilli leaf curl or chilli murda complex.
As a result of thrips infestation, leaves become smaller, thickened and brittle. Mite infestation is a characterised by elongation of leaf petiole and clustering of tender leaves at the tip of branches.
— Seed treatment with imidacloprid at five grams per kg seed is effective.
— Spray with acaricides such as dicofol at five ml per litre or wettable sulphur three grams per litre or diafenthiuron at one gm per litre or Vertemic at 0.5 ml per litre.
Utilisation of indigenous materials have confirmed that garlic chilli kerosene extract [GCK at 0.5 per cent] +nimbecidine (2.5 ml/lit) can effectively combat the problem.