Effect of manual and chemical controlling on percentage of infection of Downy mildew and seed yield of a Local Red onion

Abstract

Results indicated that manual and chemical controlling led to improve vegetative growth and seed yield ( kg / ha ) and decrease the percentage of infection of Downy mildew for both seasons . Plants of manually controlling treatment achieved a higher number of tubular blades / plant , followed by plants which were sprayed with Ronstar as compared with control treatment . The percentage of Downy mildew was reduced by manual and chemical controlling up to ( 16.13 , 16.75 and 15.70 , 16.60 % ) for both seasons, respectively ; while it increased for control to ( 35.65 and 35.25 % ) for both seasons, respectively . Seed yield increased to ( 402.93 , 384.50 and 408.63 , 397.93 kg/ha) for manual and chemical controlling for both seasons, respectively; while seed yield reduced for control treatment to ( 266.63 and 259.05 kg/ha) for both seasons, respectively .