By Clint Thompson
North Florida watermelon growers should be cautious about powdery mildew disease heading into the upcoming season. Its potential resistance to fungicide applications has industry experts like Nick Dufalt wary with the start of the season just a couple of months away.
Dufalt, a plant pathologist with the University of Florida Institute of Food and Agricultural Sciences, talked about the disease concerns at the recent Suwanee Valley Watermelon Institute meeting in Fanning Springs, Florida, last November.
“It’s definitely out there. It’s something we want to pay attention to,” Dufalt said. “If they feel a product fails, the best thing they can do is to come to someone in Extension so we can talk about it. I think we have a lot of options still available, so that’s good for us.
“We have a lot of products. We have the ability to change. If we feel there’s a failure, let’s look at it. If it’s a time when the environment is really good, you may want to, in seven days, get another product out there just to make sure we don’t have that 21-day window between sprays.”
Symptoms
For producers and scouts who will be scouting for the disease, symptoms begin as circular yellow areas on the leaves. Growth of the fungus appears as the infection progresses and can be observed on the underside of the leaves. “White powder” can be viewed on both surfaces of the leaves and stems as the tissue decays.
“There are years where it can be very devastating and it can even go on to the melon and cause some quality issues, too,” Dufalt said.
Dufalt said powdery mildew is showing up more in the Suwanee Valley region, though it wasn’t too bad during the 2021-22 seasons.