How to Manage Pests
UC Pest Management Guidelines
Ozone symptoms vary depending on the type of pollutant and concentration, the cultivar, and environmental conditions. The most common symptoms of ozone damage on field-grown beans is bronzing, in which a purple-brown discoloration develops on the upper surface of the leaves.
Ozone injury is caused by high levels of ozone (O3) 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.
UC IPM Pest Management Guidelines: Dry