P2936

Plant Doctor - Greenhouse Basil Downy Mildew

Greenhouse Basil Downy Mildew

Most common seasons

Late fall, winter, and early spring.

Weather

Rain and high humidity, especially originating from the Gulf of Mexico. Temperatures between 53 and 77°F.

Basil types affected

Especially bad on sweet basil. Colored types and other species are not so susceptible.

Quick symptoms

Chlorotic (yellow) area in center (mid-rib) of leaf. May develop fuzzy, gray growth on undersides of leaves. In very conducive situations, fuzzy growth may be on upper leaf surfaces, as well.

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This work is supported by Crop Protection and Pest Management, Extension Implementation Program, award no. 2024-70006-43496 from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.

The information given here is for educational purposes only. References to commercial products, trade names, or suppliers are made with the understanding that no endorsement is implied and that no discrimination against other products or suppliers is intended. Products, especially for residential use, change frequently. This information was accurate at the time of publication.

Publication 2936 (POD-07-25)

By Alan Henn, PhD, Extension Professor, Agricultural Science and Plant Protection.