Bacterial blight is a major disease of rice. The disease is observed in both seedlings and older plants.
On seedlings, infected leaves turn greyish green in colour and roll up. Appearance of a milky or opaque dewdrop on young lesions early in the morning is one sign of infestation.
The entire plant wilts. The infected field should be kept well drained soon after infection is detected (in conventionally flooded crops). Apply potassic fertilizer in two split doses at tillering and pre-flowering stages.
Split dosesAvoid using high doses of nitrogenous fertilizers. Go for judicious application. Apply nitrogen fertilizer in three split doses, 50 per cent basal, 25 per cent in tillering phase and 25 per cent nitrogen in panicle initiation stage.
Use fresh cow dung slurry at 2kg/10 litres of water, strain it in fine cloth and spray at an interval of 7-10 days 3-4 times at 500 litres/ha. Keep fields clean — remove weed hosts and plough well.
Use of resistant varieties like ajaya, asha, biraj, CO-43, gobind, IR-64, janaki, PR-4141, radha, sona mahsuri, sujata, suraj, swarna, udaya, swarna radha, prasad gobind and pant dhan 4 IR-20 prevents this infestation.
Reduce the disease spread by careful handling of seedlings during transplanting, maintain shallow water in nurseries.
Use only disease free seedlings. Pseudomonas fluorescens and Bacillus strain 3 FZB42 are found effective against this infestation.
Chemical controlSoak the seeds with a solution of plantomycin 10gms or streptocyclin 1.5gms and copper oxychloride 25gms in 10 litres of water. Spray the affected crop with the same chemicals at 500 litres /ha at 7-10 days intervals 2-3 times on need basis.
Streptomycin sulphate and copper oxychloride have been found superior for reducing the infestattion and increasing grain and straw yield.
(Ritika Bhattacharjee, Msc, Research scholar and Utpal Dey, Ph.D. scholar, Department of Plant Pathology, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani-431402, Maharashtra. email: utpaldey86@gmail.com. Mobile:08275824103.)
