Ripgut brome, great brome, giant brome

Scientific name: Bromus diandrus

Soft brome (Bromus hordeaceus) plant

Ripgut brome infestation

Ripgut brome infestation

Soft brome (Bromus hordeaceus) infestation

Ripgut brome seed heads

Ripgut brome seed head

Soft brome (Bromus hordeaceus) seed head

Prairie grass (Bromus wildenowii) infestation

Prairie grass (Bromus wildenowii) infestation
  • Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Annual grass with a large nodding flower head, consisting of few or many large spikelets
  • Leaves are rough and broad (about 1 cm across) on a fairly short unbranched flower stalk, 30 – 90 cm tall, that is often hairy towards the top
  • Seed head is a loose nodding panicle approximately15 – 20 cm in length
  • Ligule is prominent and membranous
  • Plants often have a reddish brown tinge and are red at the base of the tillers
  • Ripgut brome has a fibrous rooting system
  • Produces many seeds which have a short lifespan of 1 – 2 years. Seeds are large, hard and sharp, with bristly awns up to 6 cm long.

Origin and habitat

  • Indigenous to the Mediterranean region (Turkey, Cyprus, Israel and Egypt)
  • Adapted to a wide range of climatic conditions, pH ranges (acidic or alkaline), and tolerant of saline soils
  • Particularly prevalent in laxly grazed or ungrazed sites, such as stock camps, roadsides, waste places, steep sunny slopes, recently disturbed areas, and under low shrubs
  • Unaffected by legume cover, shrub presence, or altitude.

Growth

  • Flowering occurs from August through to November, triggered by the cold, short days of winter, followed by longer days in spring
  • Can tiller freely in the absence of competition
  • Each plant produces between 600 and 3500 seeds, which are dispersed by wind, animals, or as contaminants of pasture or crop seeds
  • Seed heads are formed in early summer but seeds are not released for several months. Most seeds germinate within their first year but some seeds may stay in the soil seedbank for over a year
  • Seeds do not germinate at high temperatures and low soil moisture conditions.

Impacts on pasture

  • Competes with crops and pasture for nutrients and moisture which can reduce yields (30% reduction in crop yield has been reported with ripgut brome densities of 100 plants per square metre, see references under ‘Further information’)
  • Seeds may contaminate grain and seed crops
  • Can host a wide range of serious cereal diseases.

Impacts on livestock

  • Seeds penetrate and damage the carcasses and flesh of grazing livestock (especially lambs). Awns attach to sheep’s wool and work their way to the skin
  • Seeds also reduce the value of wool and damage animal hides. Wool and meat products can be downgraded as a result, and affected lambs may have reduced growth rates.

Benefits

  • Palatable during its vegetative stage and early in its growing season, ripgut brome can provide good forage until it flowers.

  • Identify the worst paddocks on sheep and beef farms and graze with stock less susceptible to its effects, such as shorn hoggets or cattle. In particular do not graze ewes with lambs in contaminated areas between November and January
  • Salt blocks may be used as a grazing attractant to increase grazing pressure on areas infested with ripgut brome
  • Graze so as to prevent seed production over several years to exhaust the seedbank
  • Herbicides such as glyphosate can be applied to small localised patches. However, this leaves bare ground in which weed seeds can germinate. Oversowing with desirable pasture species can help in preventing further weed invasion.

Chemical control options for ripgut brome in pastures

ALWAYS READ PRODUCT LABELS BEFORE APPLYING

Active ingredient When to apply Residual effect Grass damage Clover damage
clethodim When the plants are small, preferably before tillering. Spot spray only. Moderate Severe No
haloxyfop-P As above Moderate Severe No
propyzamide and ethylene glycol As above Moderate Severe No
simazine, amitrole & dalapon As above Severe Severe No

Consult your farm consultant, industry rep or the New Zealand Agrichemical Manual for more information about chemical control.

Other brome grasses

Bromus hordeaceus         soft brome

A very common annual grass 10-100cm high, found in many pastures and in waste places.

  • Plants have an erect flower stem with relatively few spikelets, but as the plants age their flower heads can droop
  • At the seedling stage can be confused with barley grass but this species does not have auricles at the junction of leaf and sheath
  • Soft, leafy grass that is readily grazed.
Bromus wildenowii          prairie grass

A coarse, tufted perennial grass 30-120 cm tall, found in pastures, along roadsides and in waste places.

  • Flower-stem stout with hairless internodes. An erect (but later nodding) flower head, pyramid-shaped, with rough branchlets in 2s and 3s
  • Palatable to cattle even at seed head stage, and has some drought tolerance
  • Improved cultivars of this species are available.

  • Reducing ripgut brome brochure
  • Champion P, James T, Popay I, Ford K 2012. An illustrated guide to common grasses, sedges and rushes of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 208 p.
  • Gill GS, Poole ML, Holmes JE 1987. Competition between wheat and brome grass in Western Australia. Australian Journal of Experimental Agriculture 27: 291-294.
  • Kon KF, Blacklow WM 1989. The biology of Australian weeds 19. Bromus diandrus Roth and B. rigidus Roth. Plant Protection Quarterly 4: 51-60.
  • Marshall A 2014. Ripgut brome management. Lincoln University. Ripgut brome management brochure (accessed 4 August 2014).
  • Tozer KN, Marshall AJ, Edwards GR 2008. Methods of reducing ripgut brome seed production and carcass damage. Proceedings of the New Zealand Grasslands Association 70: 265- 269.
  • Tozer KN, Marshall AJ, Sedcole JR, Edwards GR 2007. Ripgut brome (Bromus diandrus) distribution in relation to topography and management on seven high country properties in the South Island. New Zealand Plant Protection 60: 168-173.
  • Young S. 2012, New Zealand Novachem Agrichemical Manual. Agrimedia Ltd, Christchurch, New Zealand.