bacteria pustule_SOYB003.JPG

Bacterial pustule

Area of impact: Leaves and pods

Description: Starts as small, dry light-green spots with raised centers. Spots are found on upper and lower leaf surfaces but can also develop on pods. Tiny tan pustules develop in the center of these spots especially on the undersides of leaves. These spots can merge to form large brown blotches.

Pathogen involved: Xanthomonas axonopodis (a bacterium)

Timing/Conditions: Occurs all season long, but the pathogen prefers warm wet weather.

Contributing factors: Overwinters in unburied crop debris and wheat roots and can be transmitted by seed.

Management practices: Plant resistant varieties and pathogen-free seed, rotate with non-host crops, avoid cultivating wet fields and deep-plow fields where the disease is common.

Ask an Agronomist