UC IPM Home > Homes, Gardens, Landscapes, and Turf > Fruits and Nuts > Diseases

How to Manage Pests

Pests in Gardens and Landscapes

Pest identification and confirmation—Bacterial blast

Bacterial blast symptoms on apple and pear are similar to fire blight. However, blast seldom affects more than 1 or 2 inches of the shoot tip, where fire blight frequently extends 1 foot or more down the shoot. The bark of twigs affected by bacterial blast is light tan and has a papery appearance, in contrast to the dark brown or black, sunken, hard appearance of twigs with fire blight. Grayish brown bacterial ooze is usually produced on fire blight lesions during humid or wet weather, but is never produced on tissue affected by bacterial blast.

Blast rarely moves past the base of shoot tip
Blast rarely moves past the base of shoot tip

Fire blight infections extend down the shoot
Fire blight infections extend down the shoot

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2013 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/GARDEN/FRUIT/DISEASE/ID/idappbloblast.html revised: May 31, 2013. Contact webmaster.