Warm temperatures and rain have caused several diseases to pop up on tomatoes and cucurbits throughout the state during the past month.
University of Kentucky extension plant pathologist Kenny Seebold said he’s seen cases of bacterial leaf spot, early blight, Septoria leaf blight and bacterial canker on tomatoes.
“The first three problems can be managed with cultural practices and fungicides; the degree of success depends on timeliness of treatment and also the length of environmental conditions that favor disease,” said Seebold, who works in UK’s College of Agriculture. “Bacterial canker, however, can be nearly impossible to stop once it gets started in the field, and there are no bactericides labeled to control it.”
He added if bacterial canker is found early on, growers can slow the disease to other plants by removing the infected ones. If the disease is found in the field, growers need to rotate away from the field for two years and sanitize stakes they plan to reuse.
Several diseases, including angular leaf spot, Alternaria leaf blight, anthracnose, gummy stem blight and powdery mildew, have affected cucurbits. Bacterial wilt is affecting a number of cantaloupes and cucumbers, and yellow vine decline is beginning to appear on some squashes and pumpkins.
As with tomatoes, growers can control the majority of these diseases with cultural practices and fungicides, with the exception of yellow vine decline. This disease is transmitted by insects, so the only way to control it is by controlling the insect vectors.
Pictures of these diseases are available in the ID-91 IPM Scouting Guide for Cucurbit Crops in Kentucky.
UK extension publications ID-36 Vegetable Production Guide for Commercial Growers and ID-128 Home Vegetable Gardening in Kentucky provide information for commercial growers, organic growers and home gardeners on available practices and chemicals to help control tomato and cucurbit diseases. All extension publications are available on the college’s website and at county extension offices.