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 started on June 7 or earlier.
The cucumber strain of cucurbit downy mildew also infects cantaloupe. All cucumber and cantaloupe growers should already have been spraying protectant fungicides. It’s now time to add downy mildew-specific fungicides to the spray program. See Land-Grant Press 1002 Cucurbit Downy Mildew Management. (Note that there was no update for 2023 as there has been no substantial change in fungicide efficacy in the past year.)
The South Carolina Grower 