Description
Ventenata (Ventenata dubia (Leers) Durieu) is native to central and southern Europe, Asia, and Africa. Ventenata has established itself in a number of states in the United States and provinces in Canada. It is currently increasing its expansion across the Pacific Northwest and will continue to spread, particularly as a contaminant in grass seed.
Ventenata is an introduced tufted annual grass, with slim, erect culms extending 6-27 inches tall. Although the stem appears smooth, tiny hairs are visible when magnified. The leaf blades are flat but become in-rolled; they are usually smooth on the upper surfaces but rough underneath. The grass’s inflorescence is an open panicle and is yellowish-brown to yellow in color. The branches of the panicle often spread until they droop. Spikelets are near the branch tips and are stalked. Ventenata has twisted and abruptly bent awns (3/8 – 1 inch in length), located on the upper florets. The upper 1-2 florets are bisexual. Ventenata’s bent awns distinguish the plant from cheatgrass (Bromus tectorum), which has straight awns but otherwise appears very similar (Figure 1). Ventenata and cheatgrass are both annual grasses that grow to similar heights and have open panicles. However, cheatgrass flowers earlier in the season (May to June), while ventenata flowers from June to August.Ventenata germinates best at moderate to high temperatures. The grass establishes in disturbed areas and is highly invasive in bluegrass, alfalfa, winter wheat, pasture, range and CRP sites. When it infests crops, it can obstruct and even damage mechanical harvesting equipment, and is known to cause loss of crop yield. Ventenata grass is unpalatable, so its spread into grazing land causes loss of forage.
Control Methods
Cultural
Prevention is always the preferred and most effective method of controlling invasive plant species, but when an invasive annual such as ventenata has already established, the strategy should be to reduce seed production. Mechanical and physical control methods are generally ineffective since the grass tends to bend rather than cut.
Mechanical
Ventenata can bind up and cause damage to harvesting equipment. Ventenata has very little nutritive value and has silica concentrations higher than most winter annual grasses other than medusahead, which in turn discourages grazing by wildlife and livestock.
Biological
There are no biological control agents for managing ventenata grass.
Chemical
Herbicides can be effective in the management of ventenata. Ventenata has shown resistance to glyphosate and sethoxydim (Weed Alert 2002). Research has been conducted in eastern Washington from 1997-2019 testing a multitude of herbicides for the management of ventenata. Research studies found that fall applications provided the greatest control of ventenata. Until recently, only one year of control could be obtained by using herbicides. The use of flufenacet/metribuzin provided variable control from year to year. The herbicide imazapic normally provides one year of control, however, injury (delayed heading, plant reduction) can occur to specific grass species. Triasulfuron, rimsulfuron, and sulfosulfuron can also provide effective control but control can be variable year to year. The most effective multi-year control can be with the use of the herbicide indaziflam.