Soft Brome-Grass Family
Soft Cheat, Soft Chess
Soft Brome-Grass Family
Soft Cheat, Soft Chess
Characteristics. As with many weeds this is an introduce species from Europe and is currently commonly found in cultivated crops and waste areas. Germination typically occurs in the fall reaching maturity in the early spring months.
Identifying Characteristics. This annual gets its name from the soft pubescence (hair) found on all above ground parts of the plant. The glumes or bracts at the base of the individual seeds on the flower head are distinctly broad and blunt. The awns are short usually around 1/4th inch in length
Bromus is a large genus of the grass family (Poaceae). Estimates in the scientific literature of the number of species have ranged from 100 to 400, but plant taxonomists currently recognize around 160–170 species. They are commonly known as bromes, brome grasses, cheat grasses or chess grasses.
Bromus is part of the cool-season grass lineage (subfamily Pooideae), which includes about 3300 species. Within Pooideae, Bromus is classified in tribe Bromeae (it is the only genus in the tribe). Bromus is closely related to the wheat-grass lineage (they are sister taxa) that includes such economically important genera asTriticum (wheat), Hordeum (barley) and Secale (rye), which are all classified in the tribe Triticeae.
Bromus species occur in many habitats in temperate regions of the world, including America, Eurasia,Australia, and Africa. There are considerable morphological differences between some species, while the morphological differences between others (usually those species that are closely related) are subtle and difficult to distinguish. As such, the taxonomy of the genus is complicated.
The genus Bromus is distinguished from other grass genera by a combination of several morphological characteristics, including leaf sheaths that are closed (connate) for most of their length, awns that are usually inserted subapically, and hairy appendages on the ovary. The leaf blades and sheaths, which comprise the leaves can be hairless, sparsely hairy or hairy. The inflorescence is a dense or open panicle, usually drooping or nodding, sometimes spreading (as in Japanese Brome, B. japonicus).
Bromus species are generally considered to have little economic value to humans, at least in present times. The Tarahumara Indians in northern Mexico use the grains of some native Bromus species to aid fermentation in making one of their cultural beverages. As names like Bromus fibrosus, Poverty Brome (Bromus sterilis) or Ripgut Brome attest, some species are not very useful as fodder because their leaves sclerotize quickly and may even be harmful to livestock due to the high silica content. Others, such as meadow brome (Bromus riparius), native to parts of Russia, are planted as forage in the Great Plains of North America. Brome grasses are not usually grown as ornamental plants due to most species' nondescript appearance. Some are useful to prevent erosion but such use must be cautiously controlled as most Bromus have the ability to spread, becoming invasive weeds. Cheatgrass (Bromus tectorum) is a particularly troublesome weed across much of western North America (from southern British Columbia to California.)
Control. Preventing seed spread. Most infestations begin in headlands and field margins. Cultivating close to the boundary drags seed further into the field. Harvest and subsequent cultivations can move seed up to 50m. Brome can be introduced via contaminated seed, feeding contaminated hay in the field or by spreading contaminated manure. Bromus species ripen later than Anisantha species and any straw removed may contain substantial quantities of viable Bromus seed.
Using the whole rotation. A non-cereal break crop enables use of a wider range of herbicides. A spring crop allows stale seedbed or fallow techniques and encourages germination. Seedlings can be killed using a non-selective herbicide pre-drilling. Use of glyphosate is very effective in fallow breaks.
Maximizing seed loss pre-drilling. In both Anisantha and Bromus species, seeds buried by plowing to 15cm depth cannot emerge so plowing provides effective control. However, high levels of brome are difficult to bury as seeds clump together and can be flicked up during plowing onto freshly plowed land. Slow plowing results in better burial. Annual plowing can be effective but a small proportion of seeds can survive at plow depth from one autumn to the next. Early drilling – before germination of brome – results in weeds in the crop; delayed drilling significantly improves control. Wait for a flush of weeds before drilling.
Managing field margins. Bromes quickly colonize bare patches in hedge bottoms or field boundaries. Sow a perennial grass mixture in these areas to prevent bromes establishing. Mow bromes within 2–6 days of flowering to prevent viable seed forming (April onwards). Ideally mow before the panicle begins to emerge.
Cultivating, or spraying off, a strip between crop and margin initially reduces populations but provides area for new seeds to germinate. Do not use uncultivated strips where brome is confined to field margins. Avoid herbicide spray drift into margins as this creates bare patches. Soft and barren brome can survive in field boundary swards with perennial grasses; mow to prevent seeding.
Plowing the outer few meters of a field at the first signs of infestation could help minimize risk of spread. Chemical and cultural control should beintegrated to provide an effective weed control strategy