Chilli is a commercial crop grown in many parts of India. The commercial crop faces many biotic and abiotic stresses starting from seed sowing to harvesting and also in post harvest storage.
The symptoms appear on above ground parts such as buds, flowers, injured leaves, side branches and green immature fruits.
Early symptoms appear on lower side of leaves. Initially water-soaked circular or irregular lesions occur that become necrotic with brown centres and thin chlorotic borders.
Lesions on leaves enlarge up to 10mm in diameter sunken on the top surface and slightly raised on the bottom. Under favourable conditions these lesions coalesce and appear blighted, and later turn yellow and drop prematurely.
The lesions become light brown and rough in appearance. Fruit lesions initially begin as pale green spots, which enlarge and become brown in colour.
These spots are raised with cracked rough watery appearance up to 5mm diameter. Wounds caused by wind, insects, mechanical injuries and sand particles on leaves and fruits are vulnerable sites of infection. Heavy, continuous and prolonged periods of rainfall favour early disease development.
Infection takes place under a wide range of temperatures with peak infection during July-September.
The bacterium spreads within the field by wind driven rain droplets, clipping of transplants and aerosols.
Spraying of Agrimycin 100 alone or with 3gm/l copper oxychloride/ copper sulphate or 2gm/l mancozeb will control the bacterium.
Disinfecting the seeds
Disinfecting the seeds for 1 minute in 1.3 per cent sodium hypochlorite solution and drying in shade is the best way to reduce seed borne bacterium.
The field should be well drained and chilli should be rotated with crops such as tomato. Resistant cultivars can be used wherever available.
(Authors: University of Agricultural Sciences, Dharwad)