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How to Manage Pests

Interactive Tools and Models: Fire Blight Risk Assessment

This program presents assessments of the risk of Erwinia amylovora infection of apples and pears, based on two models and using calculations based on weather data stored in the UC IPM weather database.

The degree-hour fire blight model assesses actual conditions for Erwinia amylovora bacterial growth and infection. It also indicates when treatment is unnecessary. It takes into account early bloom and periods of continuous cool weather, allowing adjustments in treatment timings.

The mean air temperature model predicts colonization of blossoms by the bacterium, based on daily air temperatures.

Use the models in conjunction with weather data gathered and stored in the UC IPM weather database. If possible, start the season with a full soil water profile so you can avoid irrigation during bloom, which affects the local relative humidity.

Spray considerations
Model results suggest when you will need to treat for fire blight. For complete information, see the UC IPM Pest Management Guideline for Fire Blight on Pear.

Existing orchards

None available.

Set up new orchard

Orchard name:
Weather data: UC IPM database   (Check for availability)
Start date: mm/dd/yyyy   (Selecting a start date)
End date: mm/dd/yyyy  

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright 2018 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.

Agriculture and Natural Resources, University of California

Accessibility   web template revised: November 18, 2018 Contact webmaster.