Mariana Prieto Torres is a graduate student in the Vegetable Pathology Lab at NC State University and is working on a PhD under the guidance of her major professor, Dr. Lina Quesada
South Florida Pest and Disease Hotline scouting report for November 22, 2022 including updates on Whiteflies, Aphids, Viruses,
Gummy Stem Blight, and Oomycete Diseases.
Cucurbit diseases such as downy mildew, powdery mildew, and gummy stem blight thrive in moist conditions. The current hot and dry weather conditions in Georgia have meant reduced disease pressure, which is normally prevalent this time of year.
Downy mildew (DM) is an important disease of cucumber and other cucurbits. Many quantitative trait loci (QTL) have been identified from different resistant resources but very few have been fine mapped or cloned. CucCAP researchers in USDA-ARS and the University of Wisconsin Madison reported identification and functional characterization of the candidate gene for the major-effect QTL, dm5.3, for DM resistance from the plant introduction line PI 197088. This gene, which can enhance plant disease signaling, is currently being used to breed for disease resistance in cucumber.
Downy mildew on jack-o-lantern pumpkin was reported for the region. Downy mildew has also been reported on summer squash in New Jersey and watermelon on Long Island, NY. These hosts are primarily affected by clade 1 isolates of cucurbit downy mildew. Before this, downy mildew has primarily been affecting cucumber and cantaloupe, which are largely affected by clade 2 isolates.
Epidemic Status of cucurbit downy mildew (Pseudoperonospora cubensis) displayed on the website map for 9-22-2022 on all Cucurbit hosts. Disease observations on cucumber, squash, and pumpkin were reported in the previous seven days.
Downy Mildew Found in Watermelon on Long Island.
Powdery mildew was reported on pumpkins and hard squash across the state. Downy mildew spores have been detected in all spore traps in the state’s network.