Pests

General recommendation: Seedlings in the nursery can be protected using mesh netting or yellow sticky traps. After plants are in the field, regular surveillance and spraying plant extracts are effective. Chemical pesticides should be used mainly as a corrective measure. If possible, choose a pesticide that targets the specific pest that is causing the dam­age, and avoid pesticides that kill beneficial organ­isms. Choose pesticides that have short persistence, i.e., the effects of which last only a few days. Chemi­cal pesticides should be applied in the evening, and if multiple applications are needed, rotate pesticides that have different modes of action.

The major pests found to cause serious damage to chilli crop and their management practices are detailed below:

Aphids (Aphis gossypii, Myzus persicae)

Aphids are small, succulent, pear shaped insects that vary in color from yellow to green to black.  Theses insects pierce leaves and suck the sap, caus­ing foliage to become distorted and often curled un­der. Aphids exude a sticky substance that attracts ants and leads to the development of a sooty mold on plants. Aphids are vectors to many viruses.

Control: Spraying dimethoate at 0.05% is effective for controlling aphids.

Broad mite (Polyphagotarsonemus latus)

Yellow or white, tiny, crab like insects known as mites suck plant juice near the mid vein on the undersides of the leaves causing leaves to curl downwards and become narrow. Most damage occurs between veins of young leaves. Corky tissue develops on fruits.

Control: Use of toler­ant cultivars, weed control, crop rotation, and spraying acaricides such as dicofol helps to reduce mite infestation. Spraying dimethoate at 0.05% or Spiromecifen 22.9 SC @ 96 g ai/ha or Fenpyroximate 5 EC @ 15 g ai/ha  are   is also effective for controlling broad mites.

It is also managed by the application of neem oil 5% and neem oil+ garlic emulsion 2%.

Thrips (Scirtothrips dorsalis, Thrips palmi)

Thrips are very small insects that group together along the mid vein or along borders of damaged leaf tissues. Thrips cause young leaves to curl upwards. Brown areas develop between veins of both young and old leaves. Corky tissue develops on infested fruits.

Control: Reduce thrip damage by controlling weeds, ro­tating crops, using predators and parasites, and ro­tating insecticides. Dimethoate spray at 0.05 % is effective for controlling thrips.

Tomato fruit worm (Helicoverpa armigera)

Tomato fruit worm feeds on flowers, pods and fruits of chilli. Larvae move from one fruit to the next, destroying only small portions of each fruit. Damaged fruits may drop, ripen prematurely, or be­come infected with disease. The entrance hole near the pedicel develops a dark scar. Young larvae are light yellow and spotted. Ma­ture larvae are brown to gray in color with length­wise stripes along the body and are usually found inside the damaged fruits.

Control: Monitor closely for the larvae on plants and destroy them. Remove infested fruits to reduce pest populations. Spraying any contact insecticides will help to kill ex­posed larvae.

Mealy bug

Nymphs and adults of mealy bugs suck sap from the leaves, tender shoots, and the fruits. Leaves show characteristic curling symptoms and heavy black sooty mould may develop on the honeydew like droplets secreted by mealy bugs. When the fruits are infested, it may lead to fruit drop or the fruits remain on the shoots in a dried and shriveled condition.

Control: Spraying insecticides like dichlorvos (0.02%) or quinalphos (0.025%) with fish oil rosin soap control the insect population. Unlike the adults, the crawlers are free from waxy coating and therefore the crawler stage is the most effective stage for spraying pesticides.

Root knot nematode (Meloidogyne spp.)

Root knot nematode damages the root system resulting in the formation of small galls on the roots. The infested plants become stunted and yellow. Severely affected plants may wilt. This nematode has a very wide host range. Its eggs can remain dormant for a few months. Warm temperatures and light sandy soils are conducive for its development.

Control: Cultivating resistant varieties and crop rotation; flooded rice field in par­ticular greatly reduces nematode populations. Destroy alternate hosts harbouring the nematodes. Ploughing during the fallow season will expose nematodes to sun and predators. Soil fumigants or nematicides may also be used.

Diseases

General recommendations: Use high quality, pathogen free seeds and seed­lings. Cultivate resistant varieties in disease endemic areas. High plant density leads to weak and susceptible plants, therefore use the proper plant density, both in seedling production beds and in the transplanted field. Follow clean cultivation practices, remove diseased leaves and seedlings promptly, and control weeds regularly. Many pathogens spread through irrigation water, and therefore never allow irrigation water from diseased field to enter disease free field. Prevent plants from being overloaded with fruits. Crop rotation, particularly a rice-chilli rotation, helps reduce disease and insect problems. Chilli crop should never follow other solanaceous crops as these crops share many soil borne diseases. Do not plant chilli after sweet potatoes, due to allelopathic effects. The following are some of the most common diseases on chilli:

Damping off

This is a serious disease in the nursery. High soil moisture and moderate temperature along with high humidity especially in the rainy season favour the disease. Two types of symptoms are observed, viz., pre emergent and post emergent damping off. The pre emergent damping off results in rotting of seed and seedling before emerging out of soil, whereas in the post emergent damping off, seedlings after emergence are infected near the collar region at ground level. The infected tissues become soft and water soaked. The collar portion rots and ultimately the seedlings collapse and die.

Control: For avoiding damping off of the seedlings in the nursery, sow the seeds as thin as possible in raised beds prepared in the open area during summer months. Spray nursery and main field with 1% Bordeaux mixture at monthly intervals during rainy season.Soil solarisation of nursery beds for 30 days  prior to sowing and seed treatment with Trichoderma @ 5 g/kg seed is effective in managing the disease.

Bacterial wilt (Ralstonia solanacearum)

The initial symptom is wilting of lower leaves followed by a sudden and permanent wilt of the entire plant without yellowing. Bacterial ooze streams out when cross sections of the lower stem are sus­pended in water. It is more severe on tomato, to­bacco, potato and eggplant, but it can be very dam­aging to chilli. The bacterium is found to survive in the soil for long periods. It gains entry through natural root wounds or wounds created by insects, nematodes or implements. High temperature and high soil mois­ture favour disease development.

Control: Using pathogen ree seed­beds to produce disease fee transplants and fumigating seedbeds help to contain the diseases. Use raised beds to facilitate drainage. Rotating with flooded rice, and other non usceptible crops provides limited control. Crop rotation with brinjal, tomato, and potato should be avoided. Avoid cultivation operations that damage roots. To avoid soil splash, the use of mulch and furrow irrigation, rather than overhead irri­gation, are preferred. Removal and destruction of affected plants and use of disease resistant varieties like Manjari, Ujwala or Anugraha in bacterial wilt prone areas help to reduce the disease incidence. Before sowing, the seeds should be dipped in a solution of streptocycline (1 g/ 40 litres of water) for 30 minutes. 

Anthracnose (Collectotrichum spp.)

Anthracnose may occur in the field or develop as a post arvest decay of chilli fruits. Typically, symp­toms first appear on mature fruits as small, water soaked, sunken lesions that rapidly expand. The le­sions may increase to 3-4 cm in diameter on large fruits. Fully expanded lesions are sunken and range from dark red to light tan. The disease may occur wherever chilli is grown under overhead irrigation or rainfed conditions. The pathogens can be seed borne in chilli and persist in crop debris and have a wide host range.

Control: Use seeds collected from anthracnose free fruit and treat seeds with a fungicide. Hot water treatment at 520 C for 30 minutes is also recommended. Crop rotation with non host crops and mulching to reduce soil splashing onto fruit and flowers are also effective. Avoid overhead irrigation to reduce periods of wetness on chilli fruit. Harvest fruits as soon as it ripens since anthracnose develops more readily on mature fruits. Weed regularly and avoid injuring chilli fruit. Remove and destroy infected plant debris. Avoid planting overlapping chilli crops nearby. Apply protectant fungicides to plants starting when the first fruit is set.

Phytophthora blight (Phytophthora capsici)

This disease can occur on chilli grown anywhere in the world, at any stage of growth, and on all plant parts. The most common symptom is a stem or col­lar rot followed by sudden wilting without foliar yel­lowing. Other symptoms include damping off and tip blight of young seedlings; dried tan colored lesions on foliage, as well as soft­ened fruit.

Control: Since Phytophthora blight is soil-borne and more prevalent on poorly drained soils, ensuring adequate drainage and following careful cultural practices are important for providing good control. Practice crop rotation with crops other than tomato, eggplant, and cucurbits for at least 3 years to reduce the soil inoculum. Overhead irrigation, will encourage disease spread and should be discontinued if the disease is present. 

Aphid transmitted viruses

Chilli veinal mottle vi­rus (ChiVMV), cucumber mosaic virus (CMV) and po­tato virus Y (PVY) are the major viruses that are transmitted through aphids. Symptoms vary, but generally these diseases show mosaic, mottled or deformed leaves. Plants are stunted and the loss of marketable yield can be drastic.

Control: Use of resistant cultivars, and controlling aphid vectors by destroying weeds, using insecticides, and using mesh netting to exclude aphids from seedlings provide good control.