Powdery mildew threatens crops

By Diane Palmer

powdery mildew on plantPowdery mildew is showing up on watermelon and cantaloupe plants in south Georgia and is expected to move into South Carolina this year, according to Anthony Keinath, plant pathologist.

“Dry weather favors powdery mildew over other leaf diseases, because the spores contain water that allows them to germinate on dry leaves,” said Keinath.

If powdery mildew is found, he recommends applications of the fungicides Nova or Procure and Quintec for watermelon, cantaloupe, and summer squash. Nova or Procure, which have the same active ingredient, should be rotated with Quintec.

To minimize the risk of yield loss, growers should make one preventive fungicide application and then scout fields regularly. Home gardeners can spray chlorothalonil (Daconil), sulfur, copper fungicide, or SunSpray horticultural oil to control powdery mildew.

For information: Anthony Keinath, , akeinath@clemson.edu