Prevent Cucurbit Powdery Mildew

A healthy curcurbit crop requires preventing powdery mildew damage.

Powdery mildew is one of our biggest disease challenges in cucurbits, especially in the fall, when cooler nights, heavier dews and increased rainfall create ideal conditions for fungal growth. Once early symptoms appear, crops may not recover.

It’s critical to make the first fungicide application before powdery mildew and other fungal diseases develop in cucurbit crops, then maintain a tight application schedule (every 7 to 10 days) and rotate active ingredients. DuPont™ Fontelis® fungicide (Group 7) is a good rotation option, providing preventive and curative activity that’s fast-acting and long-lasting. With a single active ingredient, Fontelis® offers rotational and tank-mix flexibility that fits into a season-long disease prevention program.

To control cucurbit powdery mildew, Alternaria leaf spot* and blight* and gray mold*, apply Fontelis® at 12 to 16 fluid ounces per acre, using the higher rate and shorter spray intervals when disease pressure is severe. No more than two sequential Fontelis® applications should be made before switching to another mode of action to help prevent fungicide resistance.

Fontelis® also controls gummy stem blight or black rot (Didymelia bryoniae), which has become a major melon disease. This disease can infect cucurbits at any growth stage, but is commonly seen in late summer and early fall. For effective control, apply Fontelis® at the full rate of 16 fluid ounces per acre.

*Fontelis® is not labeled for use in California for control of these diseases.

The information provided on this website is for reference only. Always refer to the product labels for complete details and directions for use.