Tomato Late Blight

— Written By

Phytophthora infestans is the oomycete responsible for both Tomato Late Blight and Potato Late Blight and was the cause of the 1840 Irish Potato famine.

Tomato Late Blight image by Margaret McGrath, Cornell Bugwood

Tomato Late Blight
image by Margaret McGrath, Cornell Bugwood

It also attacks other members of the solanacea family including petunia and nightshade affecting all above-ground portions of the plant. Symptoms appear first on the younger leaves as irregularly shaped lesions and white cottony growth on the underside of the leaf.

Cool (nights in the 50s-60s and days in the 80s), wet weather and clouds provide optimal conditions for the disease.

Tomato Late Blight image by Gerald Holmes - Bugwood

Tomato Late Blight
image by Gerald Holmes – Bugwood

Management

  • Grow resistant varieties
  • Plant early in the season
  • Prevent water from staying on leaves
  • Remove infected leaves, fruit, plants, and weeds

.

If you're a North Carolina resident with a question about a topic on this site, your local N.C. Cooperative Extension office can help.

Contact your local county center.

Written By

Lucy Bradley, N.C. Cooperative ExtensionDr. Lucy BradleyUrban Horticulture Professor and Extension Specialist Call Dr. Lucy E-mail Dr. Lucy Horticultural Science
NC State Extension, NC State University
Updated on Nov 10, 2020
Was the information on this page helpful? Yes check No close
Scannable QR Code to Access Electronic Version