Chris H Carlson
Kevin P Feris
Matthew Germino
Clancy J Jandreau
Brynne E. Lazarus
Jane M. Mangold
Dave W Pellatz
Philip Ramsey
Matthew J. Rinella
Morgan Valliant
Kurt O Reinhart
2019
<p><span>The exotic winter annual grass </span><i>Bromus tectorum</i><span> L. (downy brome or cheatgrass) infests millions of hectares of western rangelands. Weed-suppressive bacteria (ACK55 and D7 strains of </span><i>Pseudomonas fluorescens</i><span> Migula 1895) have been shown to reduce </span><i>B. tectorum</i><span> 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 </span><i>B. tectorum</i><span> from Montana and Wyoming. We also tested effects of ACK55 on </span><i>B. tectorum</i><span> at six field sites in Montana and one in Wyoming. </span><i>P. fluorescens</i><span> reduced </span><i>B. tectorum</i><span> germination and root and shoot lengths in Petri-plates but had no effect on plants during growth chamber plant-soil bioassays or field experiments. </span><i>Bromus arvensis</i><span> L. (field brome or Japanese brome), a species similar to </span><i>B. tectorum,</i><span> was prevalent at two of our sites, and ACK55 was ineffective against </span><i>B. arvensis</i><span> as well. Our findings contribute to a growing body of evidence that the ACK55 and D7 strains of </span><i>P. fluorescens</i><span> are not reliable tools for controlling </span><i>B. tectorum</i><span> in the Northern Great Plains, Central Rocky Mountains, and elsewhere.</span></p>
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10.1016/j.rama.2019.07.006
en
Elsevier
Weed-suppressive bacteria fail to control bromus tectorum under field conditions
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