Epidemiological factors in relation to the development of cowpea anthracnose caused by Colletotrichum dematium

Survey on the cowpea anthracnose at 17 locations in himachal Pradesh shows that disease severity ranged between 19.7–53.5 per cent being maximum (53.5%) at Palampur. Disease severity was observed maximum when plants were raised from diseased seeds followed by infested soil and diseased plant debris. Maximum spore germination (82.1%) was observed at 25°C followed by 20°C after 48 hours of incubation. With an increase in inoculum age there was corresponding decrease in the disease incidence. Maximum disease incidence (86.7%) was noticed with 15 days old culture. A negative correlation was observed between disease severity and mean temperature during both the years and at all sowing dates. Multiple regression coefficient of disease severity with mean temperature was negative, whereas, with mean rh and cumulative rainfall was mostly positive.