Developing Diseases: Increased Rains Expected to Challenge Melon Growers

Clint Thompson Disease, Georgia, Top Posts, Watermelon

University of Georgia Extension photos show phytophthora

By Clint Thompson

Increased rain events in June mean a potential increase in disease development for Georgia’s watermelon producers.

Bhabesh Dutta, University of Georgia Cooperative Extension plant pathologist, said there are a few diseases that growers need to be mindful of following excessive rain in parts of South Georgia over the past week.

“I would say I’ve been seeing a moderate level of gummy stem blight across the board. I have also seen some anthracnose in some fields,” Dutta said. “With this rain, I’m a little worried about the prospect of phytophthora fruit rot. This is perfect conditions when phytophthora can infect our fruit. Most of our watermelon growers follow stringent fungicide spray programs that include strong fungicides against phytophthora.

“This particular rain that we had over the weekend and last week, that makes me a little worried because we’re really close to harvest. This rain can affect the efficacy of fungicides that are effective against phytophthora.”

Gummy stem blight was a problem in North Florida watermelons this past May. High temperatures and humidity accompanied by frequent rain provided ideal conditions for its development. Symptoms include lesions on the stem that enlarge and girdle the main stem. Cracking is visible on the steam, along with a gummy ooze.

If growers can protect their crop against potential disease development, then they have a better chance of multiple harvests this season.

“Three (pickings) is the average. If you can get to four or five, that’s great. Some people can get six, but if you can get four to five and the market stays high, then it is quite beneficial for our growers,” Dutta said.