Downy Mildew - Peas
Established infection on leaves & visible downy mildew on underside of pea leaf
Pathogen
Fungus
Hosts
Peas and beans (field and broad)
Symptoms
A dense grey/brown velvety fungal growth develops on the underside of infected leaves and there is a yellowing of their upper surface. The fungal growth may also develop on stems and pods.
Development
Infective spores can survive in the soil for at least 8 years and attack seedlings as they emerge. The disease then spreads to the surrounding crop by air and rain splash. Oospores are formed within diseased tissue which overwinter in crop debris in the soil which infect seedlings as they emerge in the spring. The same pathogen affects both peas and beans.
Favourable Factors
Cool, wet conditions.
Importance
Yield losses can be considerable, particularly in wet seasons. Yield losses in peas can be as much as 55%.
Control
Peas and beans both have a degree of varietal tolerance
Adopt a rotation of at least 4 years between bean and pea crops
Remove crop debris after harvest
Fungicide seed treatment. A second spray 14 days later may be necessary to control severe infections.
