Gummy stem blight, powdery mildew, and downy mildew are three big diseases watermelon producers want to keep at bay. Researchers at Clemson University’s Cooperative Extension have put together a guide to help them be successful.
Knowing the symptoms of each disease is as important as knowing when to spray. According to the researchers’ step-by-step guide to spraying, growers should follow these four steps:
- Start spraying when vines start to run, no later than the first (male) blooms open.
- From vine run until mid-May, spray every 10 days
- After mid-May or when powdery and downy mildew typically show up, spray every week through harvest regardless of weather.
- Do not stop spraying until one week before the final pick. Downy or powdery mildew can attack any time a crop goes more than a week without a fungicide.