Browsing by Author "Rinella, Matthew J."
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Item Control of downy brome (Bromus tectorum) and Japanese brome (Bromus japonicus) using glyphosate and four graminicides: effects of herbicide rate, plant size, species, and accession(2019-11) Metier, Emily P.; Lehnhoff, Erik A.; Mangold, Jane; Rinella, Matthew J.; Rew, Lisa J.Nonnative annual brome invasion is a major problem in many ecosystems throughout the semiarid Intermountain West, decreasing production and biodiversity. Herbicides are the most widely used control technique but can have negative effects on co-occurring species. Graminicides, or grass-specific herbicides, may be able to control annual bromes without harming forbs and shrubs in restoration settings, but limited studies have addressed this potential. This study focused on evaluating the efficacy of glyphosate and four graminicides to control annual bromes, specifically downy brome and Japanese brome. In a greenhouse, glyphosate and four graminicides (clethodim, sethoxydim, fluazifop-P-butyl, and quizalofop-P-ethyl) were applied at two rates to downy brome plants of different heights (Experiment 1) and to three accessions of downy brome and Japanese brome of one height (Experiment 2). All herbicides reduced downy brome biomass, with most effective control on plants of less than 11 cm and with less than 12 leaves. Overall, quizalofop-P-ethyl and fluazifop-P-butyl treatments were most effective, and glyphosate and sethoxydim treatments least effective. Accessions demonstrated variable response to herbicides: the downy brome accession from the undisturbed site was more susceptible to herbicides than downy brome from the disturbed accession and Japanese brome accessions. These results demonstrate the potential for graminicides to target these annual bromes in ecosystems where they are growing intermixed with desired forbs and shrubs.Item Seeding Causes Long-Term Increases in Grass Forage Production in Invaded Rangelands(2020-03) Rinella, Matthew J.; Knudsen, Alan D.; Jacobs, James S.; Mangold, Jane M.Seeding is sometimes used in attempts to increase grass forage production in invaded rangelands, but insufficient long-term data prevent determining if seeded grasses are likely to become and remain productive enough to justify this expensive practice. We quantified long-term seeding outcomes in a widespread Rocky Mountain foothill habitat invaded by leafy spurge (Euphorbia esula L.) and several exotic grasses. Fourteen yr after seeding, the most productive grass (bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Á. Löve]) produced 900 (100, 12 000) kg ha−1 [mean (95% CI)], which was about 70% of total plant community biomass. This result was not greatly altered by grazing according to an unreplicated, grazed experiment adjacent to our replicated ungrazed experiment. Regardless of treatment, E. esula gradually became less productive and seeded and unseeded plots produced similar E. esula biomass 14 yr after seeding. P. spicata reduced exotic grasses about 85%. Our results resemble those of another foothills study of another invasive forb (Centaurea stoebe L. ssp. micranthos [Gugler] Hayek) and a Great Plains study of E. esula, so foothills seeding outcomes seem somewhat insensitive to invader composition, and seeding can increase forage across much of E. esula’s range. While there is always some risk seeded grasses will fail to establish, our study combined with past studies identifies invaded habitats where seeded grasses have a good possibility of forming persistent, productive stands.Item Weed-Suppressive Bacteria Fail to Control Bromus tectorum Under Field Conditions(Elsevier BV, 2020-11) Reinhart, Kurt O.; Carlson, Chris H.; Feris, Kevin P.; Germino, Matthew J.; Jandreau, Clancy J.; Lazarus, Brynne E.; Mangold, Jane; Pellatz, Dave W.; Ramsey, Philip; Rinella, Matthew J.; Valliant, MorganThe 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.