Weed of the Month
January's weed of the month is Ventenata (Ventenata dubia)
Why is it a Noxious Weed?
Ventenata is rapidly spreading throughout counties in Eastern Oregon, including Wasco County. Infestations have been identified in rangeland in the southern portion of the county. Like other cool season annual grasses, Ventenata competes for moisture and nutrients in the soil and outcompeting native plants. Ventenata as very little forage value for livestock and wildlife. Ventenata is beginning to replace perennial grasses and forbs along roadsides and in hay, pasture, range and CRP fields in the western United States. In addition to having minimal forage value for livestock and wildlife, Ventenata is also undesirable because its shallow root system may cause the soil to be more prone to erosion. Over time, decline of productivity and land value occurs.
Ventenata was named after a professor of botany at Paris, Pierre Etienne Ventenat, 1757-1805 (Hitchcock & Cronquist, 1973.)
How would I identify it?
Grass Family (Poaceae).Ventenata is a winter annual that germinates in the fall when temperatures are moderate to high (18C - 28C, or 64F - 82F) Northam & Callihan, 1986).
Seed heads are produced May through June, about one month following annual Bromus species. Seedling leaves are in-rolled or lengthwise folded and appear very narrow. The inflorescence is an open panicle, appearing silvery green but rapidly maturing to a yellowish-tan color. At the end of each spreading to drooping rachilla are 1-5 spikelet's. About 15-35 seeds are produced per plant (Lass & Prather, 2007).
The plant has slim, erect culms from 10 to 46 cm (4-18 in) tall with microscopic hairs that give the appearance of being smooth.
Where does it grow?
Ventenata is seen primarily in disturbed areas such as pastures, and fields. It is also commonly found on south-facing hillsides with shallow, rocky clay or clay-loam soils, though it can be found on other aspects and substrates (WSU, Noxious Weed Control Board nwcb.wa.gov).
In Oregon Noxious weeds fit into classifications;
A weed of known economic importance which occurs in the state in small enough infestations to make eradication or containment possible; or is not known to occur, but its presence in neighboring states make future occurrence in Oregon seem imminent. Recommended action: infestations are subject to eradication or intensive control when and where found.
A listed Weed:
B listed Weed:
A weed of economic importance which is regionally abundant, but which may have limited distribution in some counties. Recommended action: Limited to intensive control at the state, county or regional level as determined on a site specific, case-by-case basis. Where implementation of a fully integrated statewide management plan is not feasible, biological control (when available) shall be the primary control method.
T Designated Weed:
A designated group of weed species that are selected and will be the focus for prevention and control by the Noxious Weed Control Program. Action against these weeds will receive priority. T-designated noxious weeds are determined by the Oregon State Weed Board and directs Oregon Department of Agriculture (ODA) to develop and implement a statewide management plan. T-designated noxious weeds are species selected from either the A or B list.
How does it reproduce?
Ventanata reproduces by seed and not by vegetative means.
How do I control it?
Hand-pulling may be an effective method if the infestation site is small. Mowing in some cases may help to prevent seed production and more effective when mowed regularly throughout the growing season.
There are no approved biological control agents for Ventenata dubia.
Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordiantor.
Merle Keys, Wasco County Weed Department Supervisor
2705 E. 2nd Street
The Dalles, OR 97058
Phone (541) 506-2653
For more information see the resource pages linked below or contact the Wasco County Weed Department
Photo credit Google search: flickr.com
photo from Eastern Washington University
photo from flickr.com Google search