No Rain, Minimal Disease Pressure for Vegetable Growers

Web AdminDisease

By Clint Thompson

The lack of rainfall in recent weeks means increased irrigation usage for Georgia’s specialty crop producers. It has also meant reduced disease pressure, which is normally prevalent this time of year.

Tim Coolong, associate professor in the University of Georgia (UGA) College of Agricultural and Environmental Sciences, discusses the current scenario facing vegetable production.

Southeast drought

“Thus far, as long as growers are keeping water on them, which most of our vegetable guys do, it has kept some of the diseases down. The humidity has been really low. I’m actually doing a disease trial with broccoli and Alternaria and we inoculated it both (in Athens) and in Tifton. Disease is much, much less than last year. It has to do with the complete lack of rain we’ve had, the low humidity. Even in the mornings, normally we have dew, and it’s not been too bad,” Coolong said.

It’s not as if growers don’t have the challenge of navigating a fall crop with minimal disease pressure. Diseases are usually present and widespread.

“If you’re in like cucurbits, it’s everything. It’s downy (mildew), powdery (mildew), gummy (stem blight), across the board. In a lot of the brassicas, it’s typically the bacterial diseases that we’ll start to see; maybe some black rot,” Coolong said. “It’s not every year but some years we will have erwinia really badly. It’s usually driven by really wet, dewy, foggy mornings. There have been years where I remember in Tifton, you could go out for like 10 days straight in the morning and it would just be really wet until 11 a.m. or something. That type of weather is really good for erwinia.”

But the current hot and dry weather conditions are not good for most diseases. According to the U.S. Drought Monitor, the majority of Georgia is either abnormally dry or moderately dry. With little moisture to feed off of, diseases can’t find much of a foothold in vegetable crops. That’s just the way Georgia growers like it.

“It’s why they grow so much in California. There might be six months of the year they don’t get rain. The plants stay dry, and it makes things a little bit easier compared to the Southeast,” Coolong said.