Bacterial Pustule of Soybean
Published: 01/25/2022
Bacterial pustule is caused by Xanthomonas axonopodis pv. glycines. This disease occurs mid- to late season when temperatures are warmer. Lesions are found on outer leaves in the mid- to upper canopy. Lesions start as small, pale green specks with elevated centers and develop into large, irregularly shaped infected areas. A greenish-yellow halo surrounds each lesion. A pustule may form in the center of some lesions, usually on the lower leaf surface. Bacterial pustule will not cause leaves to tatter like bacterial blight.
Disease development is favored by hot, wet weather.
Avoid extremely susceptible varieties where disease is a potential problem; some varieties are marketed as resistant to bacterial pustule. Crop rotation and tillage reduce survival of the bacteria.
Bacterial pustule on soybean leaf.
Image: D. Mueller
A pustule may be observed in the center of lesions on the underside of leaves.
Image: A. Robertson
Bacterial pustule lesions are on outer leaves in the mid- to upper canopy.
Bacterial pustule occurs mid- to late season when temperatures are warmer.
Bacterial pustule will not cause leaves to tatter like bacterial blight.
A pustule may form in the center of some lesions, usually on the lower leaf surface.
A pustule may be observed in the center of lesions on leaf underside.
A greenish-yellow halo surrounds each bacterial pustule lesion.
A greenish-yellow halo surrounds each bacterial pustule lesion.
Soybean plant canopy with bacterial pustule.
Bacterial pustule lesions start as small, pale green specks with elevated centers.
A pustule may be observed in the center of bacterial pustule lesions on leaf underside.
This publication was developed by the Crop Protection Network, a multi-state and international collaboration of university/provincial extension specialists and public/ private professionals that provides unbiased, research-based information to farmers and agricultural personnel.
This information in this publication is only a guide, and the authors assume no liability for practices implemented based on this information. Reference to products in this publication is not intended to be an endorsement to the exclusion of others that may be similar. Individuals using such products assume responsibility for their use in accordance with current directions of the manufacturer.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD).
USDA is an equal opportunity provider and employer.
©2022 by the Crop Protection Network. All rights reserved.
