Category: Cucurbits
-
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…
-
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…
-
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…
-
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…
-
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…
-
Time to Think About Cucumber Beetles
From Tom Bilbo, Extension Entomologist As the weather warms up and our summer vegetable crops get going, it’s time to be on the lookout for cucumber beetles in our various cucurbit crops. There are three species that we see in South Carolina: banded, spotted, and striped cucumber beetles, with the latter two being more problematic…
-
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…
-
Field Scouting and Identification of Diseases on Cucurbits in South Carolina
From Clemson Plant Pathologist Tony Keinath For anyone who missed the Preplant Cucurbit Meeting on Feb. 7, 2025, at the Edisto Research and Education Center, here is a recap of the main points on scouting fields for cucurbit diseases. Table 1 shows which diseases are most likely to show up on different crops. Use this…
-
Good Progress on Breeding a Downy Mildew-Resistant Pickling Cucumber, 2024 Update
From Clemson Plant Pathologist Tony Keinath I am part of an exciting collaboration with Dr. Michael Mazourek from Clemson University to help him complete the breeding and selection process for a new pickling cucumber with high levels of resistance to downy mildew. Field work at the Clemson Coastal REC in Charleston started last fall. We…
-
Downy Mildew Found on Cucumber and Squash in Charleston
By Clemson Plant Pathologist Dr. Anthony Keinath Similar to 2023, cucurbit downy mildew was found at Coastal REC in mid-September, last Friday the 13th, on cucumber and butternut squash transplanted August 15. Interestingly, cucumbers transplanted about 2 weeks ago didn’t have downy mildew…yet. Symptoms on both cucumber and squash means that both strains of cucurbit downy…
The South Carolina Grower 