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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #311097
Title: First report of bacterial blight of crucifers caused by Pseudomonas cannabina pv. alisalensis in Minnesota on arugula (Eruca vesicaria subsp. sativa)

Author
item Bull, Carolee
item ORTIZ-LYTLE, MARIANNE - California State University
item IBARRA, ANA - Hartnell Community College
item DU TOIT, L. - Washington State University
item REYNOLDS, G. - Non ARS Employee

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2014
Publication Date: 3/1/2015
Citation: Bull, C.T., Ortiz-Lytle, M., Ibarra, A.G., du Toit, L.J., Reynolds, G.J. 2015. First report of bacterial blight of crucifers caused by Pseudomonas cannabina pv. alisalensis in Minnesota on arugula (Eruca vesicaria subsp. sativa). Plant Disease. 99:415.

Interpretive Summary: Minnesota is ranked 6th in the nation for the number of organic farms. Little is known about the impact of plant diseases in organic production, but significant arugula losses were experienced in organic production in Minnesota due to bacterial blight in 2011. The first step in reducing the impact of emerging plant diseases on crops is to identify the pathogen causing the disease. In this study, we identified the causal agent of bacterial blight on arugula as a pathogen that was not previously described in Minnesota though we had previously described it as a pathogen of arugula and other crucifers. This information will help producers make crop production choices to help reduce spread of the pathogen from one susceptible crop to another.

Technical Abstract: In 2011, bacterial blight of arugula (Eruca vesicaria subsp. sativa; cv. Roquette) was observed in organically grown plants under overhead irrigation near Delano, MN. Approximately 80 to 100% of each planting was affected. Blue-green fluorescent pseudomonads were isolated consistently on King’s Medium B agar (KMB) from symptomatic leaf tissue. Physiological tests indicated that the bacteria belonged to Lelliot’s LOPAT group 1. DNA banding patterns of rep-PCR products were identical to the banding patterns of Pseudomonas cannabina pv. alisalensis. Pathogenicity was confirmed on the arugula cv. My Way in two independent experiments. Identical replicated experiments conducted on broccoli raab indicated that the arugula isolates were also pathogens of broccoli raab (Brassica rapa subsp. rapa, the original host from which P. cannabina pv. alisalensis was isolated). To our knowledge this is the first report of bacterial blight of crucifers caused by P. cannabina pv. alisalensis in MN. Arugula germplasm is being evaluated for resistance to this pathogen as an acceptable management method for organic cropping systems.