Photo courtesy of UF/IFAS
Bob Hochmuth, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) regional specialized Extension agent for commercial vegetable crops, has reported downy mildew has shown up in the Suwannee Valley region of North Florida this week.
“It was seen in small areas at the end of last week but as downy mildew can do, it spread rapidly over the weekend,” Hochmuth noted in the UF/IFAS Extension Suwannee Valley Watermelon Crop Update. “That fast movement is a description of how it got its name ‘wildfire.’ It was found in a field that had been harvested a few times.”
Hochmuth added unless a field is wrapping up for the season, growers will want to consider adding a material to the spray tank for downy mildew.
Our suggestions include either Raman or Orondis Ultra,” he said. “The choice of Ranman may be OK if you see no signs of downy, but otherwise if any areas of downy are of concern in a field, then use Orondis Ultra. If in doubt, I suggest you use the best material we have, Orondis Ultra.
“Both have zero days to harvest Pre-Harvest Interval in watermelon. Remember both Ranman and Orondis Ultra are only targeted very specifically at downy mildew and will not help on other diseases. If you see signs of downy but are not due to spray again for a few days, you may consider a separate and immediate spray for downy mildew. The signs include the firing of the leaves and the upward cupping of the affected leaves.”
By Frank Giles