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ARS Home » Midwest Area » West Lafayette, Indiana » Crop Production and Pest Control Research » Research » Publications at this Location » Publication #198095
Title: DISEASES OF SOYBEAN: BROWN STEM ROT

Author
item WESTPHAL, ANDREAS - PURDUE UNIV.
item ABNEY, THOMAS
item SHANER, G - PURDUE UNIV.

Submitted to: World Wide Web New Crops Center Purdue University Bulletin
Publication Type: Experiment Station
Publication Acceptance Date: 6/11/2006
Publication Date: 6/11/2006
Citation: Westphal, A., Abney, T.S., Shaner, G.E. 2006. Diseases of soybean: brown stem rot. World Wide Web New Crops Center Purdue University Bulletin. Available at www.btny.purdue.edu/Pubs/index.html.

Interpretive Summary: Soybean yield losses due to brown stem rot (BSR) occur regularly. This disease is a root and vascular disease of soybean caused by the soilborne fungus Phialophora gregata. The disease has become more widespread during the past several years, and now it can be found in most soybean growing areas particularly in the northern region of the U.S. Yield losses of 16-30% have been reported in some fields in years highly favorable for disease development. Disease development is particularly damaging in years when cool, wet weather during early pod fill is followed by dry weather. Although root infections occur much earlier, brown stem rot affected plants usually show no outward symptoms of infection until later in the growing season in mid-August or later when plants are in the pod filling stages of growth or as pods begin to yellow. The disease is usually first noticed when plants in portions of a field prematurely die. The most reliable symptom for the field diagnosis of brown stem rot is revealed by splitting the lower stem of affected plants. Healthy plants have white pith tissues (tissues in the center of the stem), whereas plants affected by brown stem rot usually have dark, reddish-brown pith tissues. Control of brown stem rot is accomplished by crop rotation, the use of resistant soybean varieties, or a combination of both. There are no fungicides available for effective disease control. The information describing symptoms, disease cycle, and control outlined in this Extension Publication will provide crop specialists and soybean growers current insight into disease diagnosis and management practices that will reduce disease losses. Information presented in this Soybean Disease Bulletin will permit extension specialists to diagnose disease development and recommend disease control strategies that can be used in soybean production to minimize yield losses

Technical Abstract: Soybean yield losses due to brown stem rot occur regularly. Yield losses of 16-30% due to root and stem infections of soybean caused by the soil-inhabiting fungus Phialophora gregata have been reported in some fields in years highly favorable for disease development. This bulletin summarizes the cardinal characteristics and disease cycle associated with brown stem rot of soybeans. Crop rotation and information about resistant soybean varieties for disease control strategies are included in this bulletin. The information will be useful to extension and crop specialists in diagnosing and recommending control measures for soybean production where the disease is a major problem.