Weed-suppressive bacteria fail to control bromus tectorum under field conditions

Rangeland Ecology & Management
By: , and 



The exotic winter annual grass Bromus tectorum L. (downy brome or cheatgrass) infests millions of hectares of western rangelands. Weed-suppressive bacteria (ACK55 and D7 strains of Pseudomonas fluorescens Migula 1895) have been shown to reduce B. tectorum populations in eastern Washington. Unfortunately, outside of Washington, little is known about the efficacy of these or other weed-suppressive bacteria. We used Petri-plate and plant-soil bioassays to test effects of ACK55 and D7 on B. tectorum from Montana and Wyoming. We also tested effects of ACK55 on B. tectorum at six field sites in Montana and one in Wyoming. P. fluorescens reduced B. tectorum germination and root and shoot lengths in Petri-plates but had no effect on plants during growth chamber plant-soil bioassays or field experiments. Bromus arvensis L. (field brome or Japanese brome), a species similar to B. tectorum, was prevalent at two of our sites, and ACK55 was ineffective against B. arvensis as well. Our findings contribute to a growing body of evidence that the ACK55 and D7 strains of P. fluorescens are not reliable tools for controlling B. tectorum in the Northern Great Plains, Central Rocky Mountains, and elsewhere.

Publication type Article
Publication Subtype Journal Article
Title Weed-suppressive bacteria fail to control bromus tectorum under field conditions
Series title Rangeland Ecology & Management
DOI 10.1016/j.rama.2019.07.006
Volume 73
Issue 6
Year Published 2019
Language English
Publisher Elsevier
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 6 p.
First page 760
Last page 765
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