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Results of 2016 and 2017 Bacterial Blight Trials in Dry Beans (07/19/18)

In recent years, we have received many questions about managing bacteria blight in dry edible beans.

Results of 2016 and 2017 Bacterial Blight Trials in Dry Beans

In recent years, we have received many questions about managing bacteria blight in dry edible beans.  Traditionally, response to chemical applications have been variable in our region.  However, bacterial blight epidemics in 2016 and the availability of several new products led to further research by dry bean pathologist Julie Pasche and her Ph.D. student Amanda Beck.  Amanda evaluated many products (new and old) against the most common bacterial blight disease in our region, ‘Common Blight’. 

Information about the treatments.  The treatments used in these trials include plant growth enhancers, copper-based products or peroxide based products.  In some cases, very limited information about the products is available, but most product information is available online and can be found relatively quickly using an internet search tool.

Trial Information.  Each of the trials was conducted on NDSU Agriculture Experiment Station sites.  In all trials, plots were sandblasted to mimic wounding from thunderstorm damage, and inoculated during late flowering with the pathogen causing common bacterial blight (Xanthomonas axonopodis pv. phaseoli).  ‘Early’ chemical treatments were applied at vegetative stages (V3-V4) while all others were applied at approximately 90% bloom.  All treatments were applied twice, unless otherwise noted (Table 1), using flat fan nozzles and 10 gal/ac water. Disease severity was calculated by visually examining leaf tissue and plot damage. Viable yield data could not be collected in Fargo 2016 (rust epidemic) and Prosper 2017 (herbicide injury).

Results.  Reduced disease severity was frequently observed when products were applied (Tables 2 and 3).  ‘Early’ vegetative applications were generally less effective at managing disease (numerically or statistically) than a two- spray program beginning in July.  A high level of variation in disease control among products existed in each of the trials.  Yields were not statistically different (Table 4).

Conclusions.  Data from these trials demonstrates that many of these products can reduce bacteria blight severity, although we did not observe yield differences.  In other parts of the U.S., such as Eastern Colorado and Western Nebraska, a 2-4 spray program is used to actively manage bacterial blights.  In our region, a multi-application bacterial blight program has not been commonly used in our region because it was not cost effective.  That said, it is encouraging that severity reductions did occur in these trials. 

More Information.  More information on this work and other research projects is available in the 2018 Dry Bean Research update of the Northarvest Bean Grower Magazine, located at

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Sam Markell

Extension Plant Pathologist, Broad-leaf Crops


Julie Pasche

NDSU Dry Bean & Pulse Pathologist


Amanda Beck

Department of Plant Pathology

Doctoral Grad Research Asst.

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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