Effect of Sowing Time and Plant Population on Bacterial Blight and Yield of Cowpea

Effect of sowing time and plant density on bacterial blight (X. campestris pv. vignicola) and yield of cowpea has been tested for 3 and 2 consecutive years, respectively. July sowing was found best for cowpea as yield was maximum (15.99 and 12.78 kg/5 × 3 m) under both natural and artificial inoculations. Reduction in yield over natural was also minimum (20.07 per cent) in July sowing. The r and relative ADPC varied from 0.008 to 0.0049. 0.212 to 0.508 and 0.004 to 0.040, 0.371 to 0.706 during March to July under natural and artificial inoculation, respectively. Whereas, these were less during July to October. In general July to October sowing was best. In case of population density disease increased with the increase in plant population The r and relative ADPC ranged from 0.004 to 0 025, 0.060 to 0.201 and 0.001 to 0.018, 0.244 to 0.693 under natural and artificial inoculation, respectively. Reduction in yield in artificial inoculation over natural ranged from 25.29 to 53.50 per cent.