Top Vegetable Diseases to Watch in 2017

Top Vegetable Diseases to Watch in 2017

Southern Blight by Schwartz FEATURE

Southern blight is a problem on both the East and West Coasts. Photo by Howard Schwartz.

We sent out a call to vegetable pathology Extension agents to let us know which diseases are top of mind for growers.
Here’s what we learned:



(as reported by Anthony P. Keinath, Professor, Vegetable Pathologist, Clemson University)

Powdery mildew on watermelon. It was the No. 2 most common disease in my grad student’s survey in three growing seasons. It is often overlooked by growers.

Gummy stem blight on watermelon and cantaloupe. It was the No. 1 most common disease in my grad student’s survey (which was done on watermelon) in three growing seasons.

Southern blight on tomato and pepper. Growers in South Carolina and Georgia have been complaining about it. I just finished a three-year study on it.

Bacterial spot on tomato and pepper. Depending on year/season, bacterial spot on tomato and pepper. Limited resistance to all 10 races is starting to become available in pepper. Shifts in the bacterial species have expanded the range of this disease to include the mountain production regions for tomato.


(as reported by Amanda Jane Gevens, Associate Professor & Extension Agent, Potato and Vegetable Pathology, University of Wisconsin-Madison)

White mold of beans, potatoes, and other vegetable crops. This disease is caused by the soilborne fungus, Sclerotinia sclerotiorum, which has a very broad host ranging, included most dicotyledonous crop plants.

Black rot of brassicas. Black rot of brassica crops, such as cabbage and broccoli, caused by Xanthomonas campestris, has been a recurring problem in fresh and processing cabbage production in Wisconsin.

Several bacterial pathogens on onion continue to cause quality challenges in necks and bulbs especially when precipitation is frequent during production.

Black leg and soft rot of potato (including discovery of Dickeya species). Increased precipitation and contamination of seed have played a role in increasing the incidence and severity of these diseases in potato crops.

West Coast and the Southwest

(as reported by Joe Nunez, Extension, University of California Cooperative Extension; Steve Koike, Plant Pathology Farm Advisor, UC Cooperative Extension, Monterey County; and Michael Matheron, Extension Plant Pathologist & Professor, The University of Arizona)

• Southern Blight
• Beet curly top virus on tomatoes (vectored by beet leafhopper)
• Root knot nematode
• Verticillium wilt on lettuce
• Fusarium wilt on lettuce
• Downy mildew on lettuce and spinach
• Fusarium yellows on celery
• Septoria late blight on celery
• Bacterial leaf spot on cilantro
• Tomato spotted wilt on peppers
• Powdery mildew on peppers