Pacific Northwest Vegetable Extension Group

of Washington State University, Oregon State University, and University of Idaho

Photo Gallery of Vegetable Problems


(Click on photo to enlarge)


Disease: Downy mildew
Pathogen: The oomycete, Peronospora belbahrii

photo of downy mildew symptoms on basil
Photo Source: Chris Benedict, Regional Extension Specialist, WSU Whatcom Co. Extension

On-Line 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

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.

Photo showing symptoms of thrips feding injury on basil plants
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: Jules Riske Photo Source: Lindsey du Toit, Washington State University

On-Line Resources:

Pests – Western flower thrips, Frankliniella occcidentails and Onion thrips, Thrips tabaci. Protected Herbs: Best Practice Guide for Integrated Pest and Disease Control

How to Control Thrips on Basil. eHow

Pacific Northwest Insect Management Handbook: Vegetable crop pests – Thrips.

See Diseases, pests, and other problems common to many vegetables: Western flower thrips


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WSU Mount Vernon NWREC, 16650 State Route 536, Mount Vernon, WA 98273-4768, 360-848-6120
Contact Us: Lindsey du Toit and Carol Miles