Disease Discovery: Gummy Stem Blight a Problem in North Florida Watermelons

Clint Thompson Disease, Florida, Top Posts, Watermelon

By Clint Thompson

Wilting is common in a heavy gummy stem blight outbreak.

Fusarium wilt is not the only disease affecting North Florida watermelons. According to an email alert sent by Suwannee Valley Extension agents, the region’s watermelon crop is undergoing high gummy stem blight pressure. High temperatures and humidity along with rain showers have provided the perfect environment for gummy stem blight.

“In fact, I would be willing to bet we could find gummy infections in every field if we looked hard enough,” according to the report.

Symptoms include lesions on the stem that enlarge and girdle the main stem. Cracking is visible on the stem, accompanied by gummy ooze. Cankers develop on the stem that can be red, brown or black in color. A red to amber gummy substance can exude from the region.

Black fruiting bodies of the fungus can also be seen on infected leaves, stems and fruits. Large, brown lesions from severe infections can form on the areas of the leaves that retain moisture for long periods of time, such as around veins or leaf margins.

Symptoms differ depending on if either Miravis Prime or Inspire Super were sprayed prior to last weeks.

Growers need to apply an application of Inspire Super immediately. It is the top-rated fungicide in University of Florida/IFAS research trials.

Growers are encouraged not to spray in the hottest part of the day.