Downy mildew sunflower
Downy mildew occurs in sunflower when 2-3 inches of rain occur within two to three weeks of planting. The only control for downy mildew has been to use Apron treated seed.
Downy mildew is common in many fields, especially where heavy rains has occurred shortly after planting. Plants with systemic downy mildew are recognized by the stunted plants, yellow symptoms on the main veins and a downy white growth on the lower surface of the main veins. Occasional plants with systemic infection do not result in yield losses since nearby plants compensate in yield. When large areas of plants have systemic infection, then yield loss occurs.
Presence among species
|Plasmopara halstedii||Helianthus annuus|