Category: Disease
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Cucumber Cultivar Response to Downy Mildew
From Clemson Plant Pathologist Tony Keinath This blog is an update on the preliminary cucumber cultivar reactions to downy mildew posted on June 16, 2023. Use the info in this blog to choose cultivars. Clearly, a few cultivars had temporarily “escaped” infection, although I don’t know how that was possible. In addition, the resistances originally…
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2023 Fusarium Wilt on Seedless Watermelon Experiment – Week 7 Observations
From Clemson Plant Pathologist Tony Keinath This year’s Fusarium wilt experiment includes 3 seedless cultivars, 3 fungicide treatments applied via drip irrigation, and grafting. This experiment is supported in part by a USDA SCRI grant. Transplants were set April 5 in a field infested with Fusarium races 1 and 2. These preliminary results are based…
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Fungicide Sensitivity of Cucurbit Powdery Mildew in Charleston, SC
From Clemson Plant Pathologist Tony Keinath A fungicide sensitivity bioassay was done between June 1 and June 10, 2023, to find out which fungicides can be used against the current outbreak of powdery mildew on squash, watermelon, and other cucurbits. Methods: Yellow summer squash plants ‘Early Prolific’ with three true leaves were treated with one…
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Cucumber Downy Mildew Found in Charleston, SC
From Clemson Plant Pathologist Tony Keinath One of the rainstorms the latter part of last week (the week of June 5) brought cucumber downy mildew spores with it to Coastal REC. On June 12, the most susceptible cucumber cultivar, Straight 8, already had 50% diseased leaf area. This amount of disease suggests that the infection…
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Basil Downy Mildew Arrives in Charleston, SC
From Clemson Plant Pathologist Tony Keinath. One of the rainstorms the week of June 5, 2023, brought basil downy mildew spores with it to Coastal REC. On Friday, June 9, all four cultivars in our demonstration were healthy and more than ready to harvest. On Monday, June 12, this is what we found. Basil downy…
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Watch for Late Blight in Tomatoes
By Clemson plant pathologist Tony Keinath. The unusually cool weather in South Carolina the past two weeks and the rain from the tropical storm system over the Memorial Day weekend create favorable environmental conditions for late blight to develop on tomatoes that have not been sprayed with a fungicide in the past week. However, I’ve…
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Urgent: Powdery Mildew Found on Watermelon in Charleston, SC
From Clemson Plant Pathologist Tony Keinath. Powdery mildew was found on three cultivars of seedless watermelon at the Clemson Coastal REC on May 23, 2023. All watermelon crops in South Carolina should be 1) scouted for powdewry mildew and 2) if found, sprayed to prevent powdery mildew from reducing yields by up to 40%. When…
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2023 Fusarium Wilt on Seedless Watermelon Experiment – Week 5 Observations
From Clemson Plant Pathologist Tony Keinath This year’s Fusarium wilt experiment includes 3 seedless cultivars, 3 fungicide treatments applied via drip irrigation, and grafting. (This experiment is supported in part by a USDA SCRI grant.) Transplants were set April 5 in a field infested with Fusarium races 1 and 2. Right on schedule, symptoms of…
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Cucurbit Downy Mildew Found in SC
Prepared by Rob Last, Justin Ballew, and Tony Keinath. Cucurbit downy mildew was identified in South Carolina on 5/12/23. The identification came from butternut squash grown in a sentinel plot at the Coastal REC in Charleston. The same strain that affects butternut squash also affects watermelon and summer squash. Now that downy mildew has been…
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Bacterial Spot on Tomato: Are the Cures as Bad as the Disease?
From Clemson Plant Pathologist Tony Keinath and Extension Agent Zack Snipes. Now that tomatoes are in the ground in coastal South Carolina, it’s time to think about a tomato spray program for a disease that shows up every year: bacterial spot. Current recommendations are based on a tank mix of copper + mancozeb. The comments…
The South Carolina Grower 