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Commercial Horticulture > Comm Hort Blog > Posts > NEW DISEASE OF WATERMELON DETECTED IN ALABAMA

 It appears we may have identified a new disease of cucurbits in Alabama.  On June 8th we collected samples from plants expressing symptoms of “Cucurbit yellow vine decline” (CYVD) from a small commercial watermelon field in east-central Alabama (Fig. 4).  This would be the first report of the disease in the state.  We are trying to confirm our diagnosis with the help of USDA scientists in Oklahoma.  The disease is caused by the bacterium Serratia marcescens, and is spread by squash bugs. The disease has also been observed on squash and pumpkins, as well as melons in the U.S. 

Symptoms of CYVD include stunting, yellowing, and decline in plant vigor typically one to two weeks prior to harvest. In addition to yellowing leaves, the phloem in the plant stems turns brown.  Symptoms caused by CYVD are very similar to those of bacterial wilt, which is a disease transmitted by cucumber beetles. Although bacterial wilt has similar symptoms, the progression of the disease is much slower than cucurbit yellow vine decline. With cucurbit yellow vine decline, the plants rapidly turn yellow and wilt almost overnight.  The bacterium is able to survive the winter in the squash bugs and infect plants the following year.  Control of the disease relies on managing squash bugs early in the season. If you find any problem, please send samples to the Plant Diagnostic Lab at Auburn or contact a Regional Extension Agent for assistance.

Dr. Edward Sikora
Extension Plant Pathologist


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