Category: Cucurbits
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2023 Gummy Stem Blight Control for Watermelon Growers: Early is on Time
From Tony Keinath, Extension Vegetable Pathologist. The recent freeze in the lower part of South Carolina more than ended the 2022 watermelon season. It’s not too early to plan for gummy stem blight control in 2023 to allow time to buy the right fungicides in case of shortages. As the saying goes, early is on…
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Charcoal Rot Showing Up in Cantaloupe
From Clemson Extension Agent Rob Last and Plant Pathologist Tony Keinath. Charcoal rot was identified in a cantaloupe crop in South Carolina this week. The fungus responsible for the disease is Macrophomina phaseolina, a soil-borne fungus that survives as microsclerotia. The fungus affects more than 800 host plants. These range from corn and soybean to…
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Resistance to Tebuconazole is Widespread in the Gummy Stem Blight Fungus in South Carolina
From Clemson Plant Pathologist Tony Keinath. Cucurbit growers should reduce the use of tebuconazole to manage gummy stem blight as the pathogenic fungus has become moderately resistant to this very commonly used fungicide. Seven watermelon fields were sampled in 2019 (six fields) and 2021 (one field) in Beaufort, Bamberg, Barnwell, and Hampton counties. Of 229…
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Downy Mildew Spreads to Charleston, SC
From Clemson Plant Pathologist Tony Keinath and Extension Agent Zack Snipes. Downy mildew was found on non-sprayed “sentinel” cucumbers at Coastal REC, Charleston, SC, on June 1. Two susceptible slicing cultivars (Silver Slicer and Poinsette) had 5% leaf area diseased, while the resistant cultivars Citadel pickling and DMR-NY401 slicing and the moderately resistant Bristol slicing…
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Fusarium Wilt Symptoms in Watermelon at Fruit Set Stage
From Clemson Plant Pathologist Tony Keinath and Extension Agent Rob Last. Watermelon growers may find new plants with symptoms of Fusarium wilt as the plants start to set fruit or as fruit sizes up. In the infested field at Coastal REC, 3-5% of the plants previously rated as healthy showed symptoms in the past 2…
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Cucurbit Downy Mildew Arrives in SC
Prepared by Rob Last. Cucurbit downy mildew has been identified in South Carolina this morning (5/25/22). The identification came from a field of cucumbers in Bamberg County. Please remember to make fungicide applications seven days apart, a stretch longer than this is likely to increase the potential for disease spread. For cucumbers, some suggested products…
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Planting Cucumbers Early Avoids Downy Mildew and Increases Yield without Fungicides
From Clemson Plant Pathologist Tony Keinath Growers who have flexibility in deciding when to plant cucumbers should plant them within 1 month of the earliest recommended planting date for their region. Planting dates for commercial growers are in the Southeast Vegetable Crop Handbook (Pg 75). Planting dates for home gardeners are in fact sheet HGIC…
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Preparing for Gummy Stem Blight in Fall Cucurbit Crops
From Clemson Plant Pathologist Tony Keinath. Gummy stem blight is more common and more severe on fall cucurbit crops than crops grown in the spring. The cooler weather and longer dew periods in the fall provide an ideal environment for the fungal pathogen to grow and spread. Gummy stem blight is most common on watermelon…
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Downy Mildew on Watermelon Found in SC
From Clemson Plant Pathologist Tony Keinath. Downy mildew was found on watermelon this week in Allendale and Barnwell counties. Although downy mildew does not infect fruit, it reduces sugar content once 1 in 4 leaves (25%) are infected. All watermelons should be sprayed with a fungicide effective against downy mildew. See pages 214-215 in the…
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Cucurbit Downy Mildew Found In SC
Cucurbit downy mildew was found in SC this week in Bamberg, Barnwell, and Calhoun Counties. In each case it was found on cucumbers and for now severity seems low. This is about two weeks earlier than in the past couple years. If not already doing so, all cucumber and cantaloupe growers in SC should begin…
The South Carolina Grower 