Thursday, December 4, 2008

Management of bacterial wilt in tomato

Management of bacterial wilt in tomato
Diseases are a major hurdle in tomato cultivation, both under controlled and field conditions.
Among them bacterial wilt is most devastating on tomato causing yield losses up to 90 per cent.
The disease is also known as southern bacterial blight or solanaceous wilt. Rapid and complete wilting of normal grownup plants is a characteristic symptom of bacterial wilt.
During warm and wet climatic conditions most conspicuous symptom of sudden drooping of leaves, without yellowing, often accompanied by rotting of the stem are seen. The roots appear healthy and well developed. Cultural management
The disease can be kept under check if crop rotations are followed with crops such as maize, ragi and okra, since they can reduce the pathogen population significantly.
Soil solarisation combined with fumigation reduces the pathogen considerably.
Destruction of weeds, collateral hosts and other off season hosts will reduce the innoculum potential. Application of sawdust
Application of sawdust, peatmoss are efficient in reducing the incidence.
Application of nitrite form of fertilizers is also capable of reducing the bacterial population.
Calcium concentration in soil should be increased to have better control of wilt disease.Chemical control
Soil treatment with chloropicrin, methyl bromide or mixture of both were found effective in retarding the wilt development.
Application of bleaching powder (15kg/ha) has also been found effective against this disease.
Seedling dip with streptocycline avoids early invasion and infection by the pathogen through wounds formed during transplanting.
Bacterinol-100 can be used as dry seed dresser, for nursery spray and field application. Streptomycin sulphate or oxytetracycline when sprayed at 200ppm at 7 days interval provides good control.
Tomato varieties such as Arka Abha, Sonali, DPT-38 and Arka Alok which are resistant to bacterial wilt can be used for cultivation.Biological management
Several biological control agents such as Pseudomonas fluorescens, Bacillus licheniformis, B. cereus, B. subtilis and mycorrihiza are very effective in delaying and reducing the wilt development.
Mallikarjun Y
, Kenganal
& Byadgi, A. S.
Department of Plant
Pathology, UAS, Dharwad

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