By: Terry Kowalchuk PAg, Provincial Forage Specialist
Downy brome is an invasive species that germinates at low temperatures (3.5 to 15 C). The plant’s ability to begin growth early gives it a competitive advantage over other plants, especially in dry years. Early germination, a short life-cycle and a dense fibrous root system allow downy brome to make more efficient use of early-season water than perennial grasses. Even in dry years plants can thrive, head out and produce prolific amounts of seed. Once a seed bank has developed, seeds germinate continuously under moist conditions or go dormant during a drought, only to flourish again when moisture returns; this makes downy brome very difficult to eradicate. If not controlled, this rapidly spreading grass can quickly advance into native grass stands, choking out native species.
Downy brome is easiest to recognize when it has headed out because of its characteristic drooping tuft-like seed head with awns and its “downy” leaves. The seed heads are 5 to 20 cm long, rather dense, slender and drooping, and pale green with a purple tinge. It has up to eight nodding spikelets that are 2 to 4 cm long and have two to eight seeds each.
There is no biological control for downy brome, so a combination of cultural and chemical control is required. Cultural control includes hand picking, mowing or grazing prior to seed set. Several chemicals can be used for controlling downy brome, but in most cases they must be used early in the spring when non-target species are dormant. Refer to the Saskatchewan Ministry of Agriculture Guide to Crop Protection for a list of products and procedures.
Although most surface seeds germinate soon after they are shed, buried seeds can remain viable for up to five years, so be prepared to monitor the site and deal with new outbreaks after you have initiated controls. With sustained effort, the seed bank can be exhausted and infestations can be eradicated, but early detection and action greatly increases chances of success.
If you suspect you have downy brome and would like an identification, contact your local Regional Forage or Regional Crops Specialist, or send a sample to the Crop Protection Lab for a fee for service identification. For more information about how to eradicate downy brome, contact the Provincial Ag Knowledge Centre at 1-866-457-2377 or firstname.lastname@example.org.