By Clint Thompson
Powdery mildew disease has been observed in North Florida watermelons. Bob Hochmuth, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Regional Specialized Extension agent in Live Oak, Florida, confirmed the disease’s presence in an email this week, though most fields have not yet shown signs of the disease.
“The disease is in its initial stages where it depends on the protected microclimate of the fully grown vines to get the humidity it requires to establish and to start sporulating,” the email read. “If scouting for powdery mildew, take a closer look to leaves and stems closer to the base of the plants. Look for small yellow areas in the leaves (mostly round) and whitish growth on stems and petioles.”
If growers suspect they have lesions, hold the underside of the leaf against light, and infected tissue will appear lighter in color.
Producers should stay ahead of the disease by incorporating a fungicide that targets specifically for powdery mildew, such as Quintec, Procure or Rhyme. Though Rhyme can be applied through the drip, growers should spray it instead for better results.