Cucumber downy mildew was discovered early last week in South Carolina, according to the South Carolina Grower.
Clemson plant pathologist Tony Keinath attributed the discovery at the Coastal Research and Education Center on June 12 to a rain event that occurred the previous week. The plant, Straight 8, was observed with 50% diseased leaf area which suggests that infection started earlier.
Keinath believes that downy mildew will start to appear on other cultivars within the next week.
Vegetable producers should be aware that the cucumber strain of cucurbit downy mildew also infects cantaloupe. Cucumber and cantaloupe growers should already have applied protectant fungicides, but it is 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.)