A problem on a wide variety of plants. Yellow, discoloured areas develop on upper leaf surfaces with greyish -white fungal growth beneath. Eventually spreads over the entire leaf or plant. Downy mildew is common on young plants and those growing in moist environments. Symptoms may be confused with those of Powdery Mildew.
Cultural measures: Remove infected leaves immediately and improve air circulation around plants and in greenhouse.
Remove all debris around plants. Avoid overhead watering. Practice crop rotation.
There is currently no chemical control available for this problem.