Effect of plant age and duration of leaf wetness on pea powdery mildew development

Studies on the effect of plant age the susceptibility to pathogen revealed that plant age has no direct relationship with powdery mildew appearance in pea. There was non-significant differences in disease severity when plants were inoculated at different days after sowing. Whereas the disease severity increased significantly with age upto 70 days after sowing beyond which there was non-significant increase in disease severity. The incubation period of the pathogen ranged between 8-12 days. The effect of wetting periods on infection of pea with Erysiphe polygoni indicated that powdery mildew severity increased progressively with increase in duration of leaf wetness upto 36 hrs but the increasing rate of disease severity was observed more upto 24 hrs. Thus, 24 hrs leaf wetness after inoculation was found optimum for powdery mildew development in pea plant.