Alert: Florida Watermelon Producers Wary of Increased Disease Pressure

Clint Thompson Disease, Florida, Top Posts, Watermelon, Weather

File photo/Wilting is common in a heavy gummy stem blight outbreak.

Rainfall over the weekend in north Florida has watermelon producers wary of potential diseases that could potentially occur. Bob Hochmuth, UF/IFAS Regional Specialized Extension agent in Live Oak, Florida, cautions farmers to look for any new symptoms that could occur.

“Most of our fungicides are in fact preventative. Trying to play catch-up with a preventative fungicide after a disease has gotten started is not the best plan,” Hochmuth said. “There are some systemic fungicides that have good activity once we see the disease start. But for sure, we want to try to stay on a really good, early-season preventative maintenance program. What we try to do as we move into these next few weeks is to keep a close eye on new diseases and then begin to target the fungicide application to the best-case scenario for the diseases that show up.

“We don’t have a lot of silver bullets to correct a problem once it occurs.”

Farmers Prefer Dry Conditions

Florida watermelon producers prefer a dry production season since the crop is vulnerable to various diseases. Farmers utilize drip irrigation to supply ample amount of water. But any extra moisture leaves the crop susceptible to potentially devastating diseases.

“The drier conditions typically help reduce the disease pressure. The only exception to that is powdery mildew. It can still be a problem, even in dry weather,” Hochmuth said. “But the other diseases, the primary ones being downy mildew, gummy stem blight and bacterial diseases, those are all encouraged by, especially, multi-day rain events.”

He added that watermelon fields were disease-free heading into the weekend. But chances are that could change this week.

“There was pretty significant rainfall throughout the watermelon growing region. A little bit on Friday but pretty significant on/off showers over the weekend,” Hochmuth said. “We were clean going into the weekend I feel like. We haven’t really seen anything other than the fusarium wilt, which has nothing to do with rain.