Panhandle Perspectives - April 4, 2017

Ventenata Grass – invasive species that may come to western Nebraska

By Gary Stone, Extension Educator, Panhandle Research and Education Center, Scottsbluff

Early Detection and Rapid Response (EDRR) is a concept to identify potential invasive species prior to or just as the invasive is becoming established.  An integrated pest management plan can be developed to manage, contain and eradicate the invasive species before it can spread further.  This will avoid costly, long-term control efforts.

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Gary Stone

Two invasive grasses, Ventenata and Medusahead, have been identified in parts of Wyoming. Both of these invasive grasses are slowly spreading east. While neither has been identified in Nebraska, it’s important to be aware of what these grasses look like, how they spread and be ready to deal with them should they show up in our state.

If they would become established in the Pine Ridge area or the Sandhills, they could be devastating to the ecology and range production.

This article is about Ventenata, also known as North Africa grass, Wiregrass, Avena dubia Leers, and Ventenata avenacea Koel. Its scientific name is  Ventenata dubia (Leers) Coss, and it is of the Poaceae / Gramineae family.

Originating in western Asia, southern Europe, and northern Africa, it was first reported in North America in 1952. Ventenata is found in the northwestern and northeastern states of the United States and the western and eastern provinces of Canada.

Ventenata is an exotic, invasive, self-pollinated, shallow-rooted winter annual grass. It germinates in the fall and overwinters as a seedling. It is typically 4-20 inches tall. The leaves are folded or rolled lengthwise and appear narrow and each plant may produce 15 to 35 or more seeds.

The inflorescence is an open panicle, pyramidal in shape. The nodes turn a reddish-black color in May-June. Awns become twisted and bent when plant senesces in July-August.

Ventenata is tawny to light yellow in color. Seed longevity is two to three years. Ventenata has been shown to displace cheatgrass and Medusahead.

Ventenata has a high silica content and is slow to decay. Its seed can be transported long distances by contaminated seed, crops, hay, animals and human activities. The long Ventenata seed awns help the seed adhere to clothing and hair of animals to help with its dispersal.

Ventenata is generally found on south-facing slopes with heavier, rocky soils. Its high silica content makes it a less desirable forage. It can be grazed early; timing is important.

Ventenata grass heads
Ventenata grass plant

Top: Ventenata/North African Grass seed heads. Bottom: Grass plant. (Photos by Prof Matt Lavin-2008/Bozeman, Mont.)

Ventenata can replace desirable perennial grasses and forbs in rangeland, pastures, CRP and hay meadows. Heavy infestations can reduce forage production by 50 percent within a few years. With the loss of production, land values decrease and ecological biodiversity is severely impacted.

Under rangeland and pasture situations, proper grazing management practices that maintain a diverse and healthy native plant community are very important in preventing establishment of Ventenata. 

Burning shows no promise as a control measure. Ventenata’s rapid growth early in the growing season allows it to flourish after prescribed burns.

Hand pulling and removal in small sites can be effective, but labor intensive. Rotary mowing Ventenata multiple times prior to heading after each flush may be useful as a control measure to reduce seed formation. Revegetation must be carefully considered due to timing and precipitation events needed for germination of the desirable species. 

Chemical applications can be effective, but costly. A number of herbicides are labeled for Ventenata management, including Glyphosate, Imazapic, and other products. Be sure to read, understand and follow all label directions. Timing of application of the products can be critical for proper control expectations.  Follow-up treatments may be required.

An integrated management approach is required to control Ventenata. Prevention is the best means of control. Utilizing more than one management option will often have a greater effect than using a single option.

Monitoring and follow-up treatments are usually required to keep Ventenata in check and limit its spread.