Editor: Cesar Escalante                                                                                                

Extension Plant Pathologist

escalac@purdue.edu

812-886-0198

August 14, 2026

MELCAST fungicide recommendations indicate a split trend across Indiana locations this week. While many southern and central production areas maintain a steady 14-day spray interval, significant EFI point accumulation requires a rapid tightening of schedules in the north and east.

For cantaloupes, most state tracking stations remain at a full 14-day spray frequency due to very flat cumulative EFI values. However, weather conditions in northern and eastern Indiana indicate a need to shorten spray intervals. Growers in Williamsburg, LaGrange, Wanatah, and Goshen are encouraged to transition to a 6- to 7-day protective schedule.

For watermelon, MELCAST shows a more volatile pattern across the state. Wanatah, LaGrange, Williamsburg, and Goshen require a 7- to 8-day spray program. Intermediate risks have also triggered tighter mid-range suggested schedules in several locations: West Lafayette (11 days), Ft. Vallonia (12 days), and Merom Station, Oaktown, and Washington (13 days). Standard 14-day intervals apply only to Decker, Marshall, Princeton, Purdue Ag Center, Starlight, and Vincennes.

Gummy stem blight and anthracnose continue to threaten fields. Regular scouting is essential. Utilize a combination of preventive and curative products, choosing fungicides based on specific field observations. If symptoms are actively spreading, prioritize highly curative fungicides and rotate FRAC groups to prevent resistance.

Downy mildew risks remain elevated in northern Indiana following regional cucumber reports. Keep a close watch on cantaloupe and watermelon plantings, and apply preventive measures if localized humidity or rainfall patterns persist. Maintain preventive measures against Phytophthora blight in low-lying, poorly drained rows.

I hope you are having a safe and successful harvest season. Please contact me directly with any field observations or questions.