Bean Plant Bronzing & Sunscald

Appearance

• Reddish-brown flecking appears on upper leaves of plants affected by bronzing. In the early stages, bronzing can be confused with some bean diseases. Sunscald appears on bean pods as reddish-brown discolorations with the possibility of leathery pods.

Environmental Causes

• Noninfectious, bronzing is the direct result of ozone pollution; all plants in the garden can be affected. Sunscald most often occurs on outside rows receiving direct sunlight; the cause is loss of water due to wind or heat.

Weather Conditions

• Prevalent during warm weather, bronzing occurs in plants in moist soil. Intense sunlight following periods of high humidity, and overcast skies create optimal conditions for sunscald.

Prevention

• Occurrence of bronzing can be reduced by choosing cultivars that show resistance to ozone. Chemicals can also be applied to protect plants. Reduce sunscald by retaining foliage above the pods. Shade fabric draped on hoops over plants can increase protection.

Crop Loss

• Bronzing can result in stunted plants and widespread crop loss. Affecting mainly plants on the edges of gardens, sunscald losses are not extensive.