Field evaluation of various chemicals and bioagent against bacterial blight of desi cotton

Bacterial blight cause yield losses in cotton crop worldwide. Losses are less when only leaves are infected but when stem lesions are formed, the losses may be high as upto 90%. The experiment was planned to evaluate the twelve spray treatments viz. 10 chemicals, one bioagent and one untreated control in natural field conditions against Xanthomonas axonopodis pv. malvacearum causing bacterial blight of cotton in Desi variety. First Spray was given at first apperance of disease and subsequent two sprays were given at 15 days interval. Observations on disease incidence (PI) and disease severity (PDI) were recorded before one day of each spray. Amongs the chemicals and bioagent tested the results obtained after third spray indicated that significantly lowest disease incidence of 20.84 % was recorded by the treatment streptocycline + copper oxychloride followed by the treatment streptocycline + carbendazim (20.92 %), streptocycline + copper hydroxide (20.96%), bordeaux mixture (21.35 %), but all four treatments found atpar in succession as against the unsprayed control 51.18 per cent (PI) and lowest disease severity of 10.22 % was recorded by the treatment streptocycline + Copper oxychloride followed by the treatmentstreptocycline + carbendazim (11.33 %), streptocycline + copper hydroxide (13.00 %), streptocycline (13.45%).