Tag: disease management
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Spray Strategies for Strawberry Disease Control in South Carolina
Guido Schnabel, Extension Plant Pathologist Disease management is essential for growing high-quality strawberries in plasticulture. While Botrytis fruit rot (BFR) is a disease you can expect every year, Anthracnose fruit rot (AFR) and the more recently introduced Neopestalotiopsis fruit and crown rot (Neo-P) may or may not appear (Fig. 1). This largely depends on how…
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2025 Recommendations For Fall Chemical Treatments In Strawberry Crops
By Guido Schnabel, Clemson University; Phil Brannen, University of Georgia; Bill Cline and Caleb Bollenbacher, North Carolina State University Whether or not Neopestalotiopsis (Neopest) will harm your strawberries this season depends on many factors – including the quality of the transplants, the cultivar, sanitation practices, soil inoculum levels, weather conditions, and the fungicides you use.…
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Reminders about Managing Cucurbit Downy Mildew with Fungicides
From Clemson Plant Pathologist Tony Keinath Cucurbit Downy Mildew This Fall Warm days and cool nights help create long dew periods in the fall, weather is ideal for cucurbit downy mildew (CDM) to start and spread, as reported in the Weekly Field Update – 9/15/25. We have not yet seen CDM in our fall sentinel…
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Why Reusing Watermelon Plastic for Watermelon is a Very Bad Idea and Other Plant Pathology Horror Stories
From Clemson Plant Pathologist Tony Keinath Extension agents have recently received some questions from growers about reusing plastic from a spring watermelon crop for a fall watermelon crop. This scenario is what I call a classic plant pathology “horror story.” It is literally the worst thing a watermelon, cantaloupe, or cucumber grower could do for…
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2025 Recommendations to Manage Powdery Mildew on Cucurbits
From Clemson Plant Pathologist Tony Keinath Results from a June 2025 bioassay with powdery mildew on susceptible yellow summer squash ‘Early Prolific’ showed that, although all 8 fungicides reduced powdery mildew, 4 worked better than the rest. The Best Fungicides To Manage Powdery Mildew on Cucurbits Torino, Quintec, Gatten, and Vivando completely suppressed powdery mildew…
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Gray Leaf Spot on Heirloom Tomatoes
From Clemson Plant Pathologist Tony Keinath Gray leaf spot has been found in a home garden in Greenville County and on a farm in Charleston County, South Carolina. This disease is the most common foliar problem on heirloom tomatoes. ‘Cherokee Purple’ is particularly susceptible. The recent hot, humid, rainy weather is ideal for the gray…
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Biologicals and Their General Performance Against Strawberry Diseases
Johanna Wesche and Guido Schnabel, Clemson University “Do biologicals work?” That is a frequently asked question coming not only from strawberry growers, especially in light of increasing resistance issues with many of the conventional fungicides and the fungicide insensitivity of Neopestalotiopis sp. In our recent article, “Biologicals Made Easy: Grouping and Understanding Biological Fungicides,” we…
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Sudden Wilt or Pythium Root Rot On Mature Cantaloupe
From Clemson Plant Pathologist Tony Keinath After a very dry April, the heavy rains in May triggered a case of Pythium root rot in one cantaloupe field in South Carolina in the past 2 weeks. Another name for Pythium root rot on mature cucurbits is “sudden wilt” to distinguish it from the more common damping-off…
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Cucurbit Disease Update for Mid-May 2025 (Downy Mildew Found in SC)
From Clemson Plant Pathologist Tony Keinath Despite relatively dry conditions this spring, two foliar diseases have shown up on cucurbits in different parts of South Carolina. Gummy stem blight was found on watermelon in the Central Savannah River Area, and downy mildew was found on cucumbers at Coastal REC. Five of 23 watermelon samples (that’s…
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Cucurbit Downy Mildew Fungicide Trial Report for Fall 2024: Part 1, Pickling Cucumber
From Clemson Plant Pathologist Tony Keinath In fall 2024, fungicide programs were tested on ‘Gershwin’ pickling cucumber to find out which programs worked best. Eight fungicide programs (plus a non-sprayed control) were used with various combinations of chlorothalonil (Bravo), Ranman, and Orondis Opti (Orondis + Bravo pre-mix). Cucurbit downy mildew (CDM) symptoms were noticed on…
The South Carolina Grower 