Category: Disease
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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…
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Cottony Rot on Stored Carrots
From Clemson Plant Pathologist Tony Keinath. Stored carrots can rot if they are infected by one of several different fungi in the field. Among the culprits is Sclerotinia, typically known as white mold on beans, Sclerotinia stem rot and watery soft rot on brassicas, or timber rot on tomato. On carrot, the same disease is…
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Pythium Damping-Off of Seedless and Pollenizer Watermelons
From Clemson Plant Pathologist Tony Keinath. Stand loss in transplanted spring seedless watermelons is usually not a serious issue in South Carolina, due to relatively sandy soils in the major production areas. Two pathogens that can cause post-transplanting damping-off and plant death are the fungus Fusarium and the water mold Pythium. Fusarium can kill seedlings…
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Black Rot Review: How to Manage this Disease on Brassica Crops
From Clemson Plant Pathologist Tony Keinath. Black rot is the most common disease caused by bacteria on brassica crops. It was widespread in the Lowcountry in fall 2022, so it’s time for a review of this serious disease. Recognizing Black Rot Most often, black rot starts at the edges of the older leaves on brassicas.…
The South Carolina Grower 