How to Manage Pests

Pests in Gardens and Landscapes

Air pollution or ozone injury to beans

Ozone symptoms vary depending on the type of pollutant and concentration, the cultivar, and environmental conditions. The most common symptoms of ozone damage on beans is bronzing, in which a purple brown discoloration develops on the upper surface of the leaves. Fruit set in green beans may also be affected.


Ozone injury is caused by high levels of ozone in the air. Ozone is generated by the interaction of atmospheric components and the products of combustion engines. The problem is favored under conditions of high temperature and light intensity. Some tolerant cultivars are available.

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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