📢South Florida Pest and Disease Hotline📢
🍉 Increasing whitefly numbers, squash vein yellowing virus, cucurbit yellow stunting disorder virus, and papaya ringspot virus, Powdery mildew, Cucurbit downy mildew 🥒
Powdery Mildew
Downy Mildew and Powdery Mildew
CucCAP Plant pathologists discussed cucurbit diseases reported by growers in Growing Produce Magazines’ 2023 State of the Vegetable Industry Survey. CucCAP plant pathologists provided information about Cucurbit Downy mildew and Powdery mildew for this article.
Hausbeck Lab Plant Disease Management Reports
In 2022 and 2023, the Hausbeck Plant Pathology Lab evaluated pickling cucumbers, acorn squash, and hard squash.
Fungicide resistance a concern for watermelon growers
Symptoms begin as circular yellow areas on the leaves. Growth of the fungus appears as the infection progresses and can be observed on the underside of the leaves. “White powder” can be viewed on both surfaces of the leaves and stems as the tissue decays.
South Florida Pest and Disease Hotline | Dec. 3, 2023
Widespread Cucurbit yellow stunting disorder virus (CYSDV), squash vein yellowing virus (SqVYV), and cucurbit leaf crumple virus (CuLCrV) infestations have been reported on watermelon in multiple locations. Crumple virus and yellow stunt virus are now common in mature watermelon fields with low levels of vine decline.
Gummy stem blight is reaching moderate to high levels in watermelon fields.
Low levels of Anthracnose on watermelons.
Powdery mildew and Downy mildew was reported in cucumber and squash. Downy mildew is expected to increase in melons due to the recent rain.
Three steps for Powdery mildew management
Components of a good PM management program:
1. Choose PM-tolerant or -resistant hybrids whenever possible to maximize host plant resistance against this disease.
2. Scout for PM beginning mid-summer on the upper and lower leaf surfaces throughout the field and leaf canopy. If even a few colonies are found, treatment should begin immediately and continue until harvest.
3. Know the Fungicide Resistance Action Code (FRAC) or mode of action (MOA) number (found on the label) for each fungicide used on your farm and how to rotate it.
Clemson Crop Update | 10/30/23
Squash are still hanging on, but with increased disease pressure from powdery mildew and the occasional out break of downy mildew. These plantings are on their last leg and are recommended to be terminated.
Powdery mildew management | VGNews
Plant Pathologists at Land Grant Universities conduct fungicide efficacy trials on cucurbits to determine spray programs to recommend. Results of these trials are published in Plant Disease Management Reports.
