The History and Distribution of Downy Brome (Bromus tectorum) in North America

Abstract

Downy brome (Bromus tectorumL. # BROTE) has developed into a severe weed in several agricultural production systems throughout North America, particularly on rangeland and in winter wheat (Triticum aestivumL.). Several million hectares of winter wheat, pastureland, alfalfa (Medicago sativaL.), grass seed fields, and overgrazed rangeland, as well as other crops, have been invaded by this annual grass since its introduction into this hemisphere. Downy brome is most abundant in the Great Basin and Columbia Basin areas of the western United States, but is found throughout the continental United States and parts of Canada and Mexico. In some cases, the vegetation on overgrazed rangeland consists totally of downy brome, while winter wheat growers in the western United States proclaim it as their worst weed problem. Changes in tillage practices that are currently being implemented for the control of soil erosion coupled with the lack of selective herbicides for the control of downy brome have aided its increase and spread.

Acroptilon repens, an Asian invader, has stronger competitive effects on species from America than species from its native range

“…Interestingly, several of the Eurasian natives, other than Acroptilon, are also invaders in North America, and in fact a substantial proportion of the overall competitive effect came from B. tectorum, a global invader and a highly competitive species (Harris 1967;Morrow and Stahlman 1984;Vasquez et al 2008), which suppressed P. spicata as much as P. spicata was suppressed when grown with Acroptilon (-56.15 ± 13.88% vs. -59.04 ± 8.93%, F 1,16 = 0.033, P = 0.858). Poa bulbosa has also become widely distributed in North America but suppressed its North American neighbor, P. alpina very little (3.87 ± 13.97%).…”

Potential Management Alternatives for Invaded Rangelands in the Northern Great Plains

“…12 Both cheatgrass and Japanese brome, also known as fi eld brome (Bromus arvensis L.), have been noted as invasive species of grasslands and agricultural areas within the western United States including the Northern Great Plains, invading millions of hectares nationwide for over 80 years. 13,14 The impact of annual bromes on ecological communities such as sagebrush steppe is common knowledge, transforming once diverse communities into monocultural stands of annual bromegrasses. 15 In the Northern Great Plains, annual bromes have been shown to decrease the above-and belowground seasonal biomass within rangeland communities; 16 however, their removal has been shown to increase native graminoid production over time.…”

MON 37500 Soil Residues Affect Rotational Crops in the High Plains1

“…Downy brome (Bromus tectorum L. # 3 BROTE) is a troublesome winter annual in the winter wheat-fallow rotation areas of the United States, especially where residue management is used for erosion control (Morrow and Stahlman 1984). Germination, growth, and development of downy brome is similar to winter wheat thus there are few effective controls in wheat (Thill et al 1984;Wicks 1984).…”