Editor: Cesar Escalante                                                                                                

Extension Plant Pathologist

escalac@purdue.edu

812-886-0198

August 20, 2026

MELCAST data indicate that many locations in Indiana currently fall within a 14-day spray interval for cantaloupes. Slightly shorter intervals of approximately 12 days are recommended for LaGrange and West Lafayette, while Wanatah is currently at a 10-day interval. Williamsburg remains the location with the shortest recommended interval for cantaloupe at 8 days.

For watermelon, spray intervals are more variable. Locations near Decker, Oaktown, Princeton, Purdue Ag Center, Starlight, Vincennes, and Washington currently have recommended spray intervals of 14 days. Merom Station and Ft. Vallonia are at 11 days spray intervals. Goshen, Marshall, LaGrange, and West Lafayette each have a recommended interval of 9 days. The shortest intervals are found at Wanatah and Williamsburg, where current recommendations are 7 days.

As the season approaches its end, growers often ask when the final fungicide application should be made. In most situations, the last fungicide spray should occur approximately 10 to 14 days before the final harvest. Most fungicides used for foliar disease management provide protection for about this length of time. Making applications closer to harvest will unlikely offer significant additional benefit. Furthermore, diseases such as downy mildew (this year only reported in northern Indiana), gummy stem blight, and powdery mildew primarily affect foliage and vine health rather than the fruit itself. Consequently, fungicide applications made only a few days before harvest are often unnecessary and may not be economically justified.

When considering late-season applications, growers should also pay close attention to the Pre-Harvest Interval (PHI) listed on fungicide labels to ensure compliance with label requirements and food safety standards.

This report marks the final MELCAST update for 2026. I appreciate the continued support and participation of Indiana growers, crop consultants, Extension personnel, and industry partners who utilized MELCAST this season. Comments and feedback are always welcome and help improve future recommendations. I look forward to working with Indiana cucurbit growers again during the 2027 growing season.