Downy mildew—Plasmopara
viticola
Downy mildew causes yellowish and oily or angular, yellow to reddish and brown lesions on leaves. Lesions
are limited by the veins. Sporulation of the fungus appears as dense, white, cottony growth in the lesions.
Infected shoot tips and petioles thicken and curl and eventually turn brown and die. Young berries appear
grayish.
Life cycle
Solutions
The best way to control downy mildew is by prevention. Preventative management consists of effective
soil drainage and reduction of sources of overwintering inoculum, such as pruning out the infected ends
of shoots. Extend the interval between sprinkler irrigations as long as possible. | 
Downy
mildew lesions on grape leaves |
