Extension Network Sites > Pacific Northwest Vegetable Extension Group > Photo Gallery of Vegetable Problems > Basil

Basil

Diseases

Insect/Mite Pests

(Click on photo to enlarge)

Diseases

Downy mildew

Disease: Downy mildew
Pathogen: The oomycete, Peronospora belbahrii

downy-mildew symptoms on a basil leaf — Photo Source: Chris Benedict, Regional Extension Specialist, WSU Whatcom Co. Extension

downy-mildew on basil leaf bottom — **Photo Source:** Chris Benedict, Regional Extension Specialist, WSU Whatcom Co. Extension

Basil-downy-mildew symptoms — **Photo Source:** Chris Benedict, Regional Extension Specialist, WSU Whatcom Co. Extension

Online Resources:

Pacific Northwest Plant Disease Management Handbook: Basil, Sweet (Ocimum basilicum) – Downy Mildew.
Expect and Prepare for Downy Mildew in Basil, Vegetable MD Online, Cornell University.

Insect/Mite Pests

Thrips

Disease: Thrips, including western flower thrips, onion thrips, and other species.
Latin binomial: Various thrips including Frankliniella occidentalis (western flower thrips) and Thrips tabaci (onion thrips).
Host Crops: Numerous plant species including many vegetables such as basil, broccoli, cabbage, cauliflower, cucumber, onion, potato, pumpkin, spinach, squash, tomato and watermelon.

Symptoms of basil thrips — Symptoms of thrips feeding injury on basil plants. Thrips tend to aggregate in the buds, feeding on succulent new leaves. This results in misshapen leaves as the damaged leaves expand, thickening and scarring of the leaf tissue, and even holes in the leaf blades.
**Photo Source:** Lindsey du Toit, Washington State University

Symptoms of thrips feeding injury on basil plants. Thrips tend to aggregate in the buds, feeding on succulent new leaves. This results in misshapen leaves as the damaged leaves expand, thickening and scarring of the leaf tissue, and even holes in the leaf blades.
**Photo Source:** Lindsey du Toit, Washington State University

basil-thrips results results in misshapen leaves as the damaged leaves expand — Symptoms of thrips feeding injury on basil plants. Thrips tend to aggregate in the buds, feeding on succulent new leaves. This results in misshapen leaves as the damaged leaves expand, thickening and scarring of the leaf tissue, and even holes in the leaf blades.
**Photo Source:** Lindsey du Toit, Washington State University

basil-thrips results holes in the leaf blades — Symptoms of thrips feeding injury on basil plants. Thrips tend to aggregate in the buds, feeding on succulent new leaves. This results in misshapen leaves as the damaged leaves expand, thickening and scarring of the leaf tissue, and even holes in the leaf blades.
**Photo Source:** Lindsey du Toit, Washington State University

Online Resources:

Pests – Western flower thrips, Frankliniella occcidentails and Onion thrips, Thrips tabaci. Protected Herbs: Best Practice Guide for Integrated Pest and Disease Control.
Pacific Northwest Insect Management Handbook: Vegetable crop pests – Thrips.
See Diseases, pests, and other problems common to many vegetables: Western flower thrips.

PDF Accessibility

If you need the content provided on this site in an alternate format or for further information on the Vegetable Seed Pathology program,

please contact: Lindsey du Toit at dutoit@wsu.edu or at 360-848-6140.

Our pages provide links to external sites for the convenience of users. WSU Extension does not manage these external sites, nor does Extension review, control, or take responsibility for the content of these sites. These external sites do not implicitly or explicitly represent official positions and policies of WSU Extension.