Research on Ventenata Control

The Current Research on Ventenata Control

By Ian McGregor Oregon State University, Assistant Professor (Practice) of Livestock & Irrigation, Klamath County

You may have heard of invasive grasses like Cheat- grass (Bromus Tectorum) and Medusahead (Taeniatherum Caput-Medusae). They are not very palatable for livestock and are also very difficult to control. To make matters worse, there is another species we can add to that list; Ventenata (Ventenata Dubia). Ventenata is a winter annual grass that is native to northern Africa and southern Europe. It was discovered in the state of Washington in the 1950’s and has only become a concern as an invasive grass about 15 years ago.

Another common name for Ventenata is Wire Grass. This refers to the wiry texture of the grass, making it notably unpalatable for livestock. The disadvantages of this invasive annual grass don’t end there. It is also a fine fuel concern that greatly increases wildfire risk, it has a very shallow root system that will lead to erosion, and it can also host Barley Yellow Dwarf virus which can be det- rimental to cereal crops. It is also incredibly invasive. The real issue is how quickly it invades rangelands, but it is also very capable of outcompeting rhizomatous perennials in irrigated pastures.

It is important that we understand control options in an effort to get ahead of this issue. Since it has not been a real issue until recent years, there has not been a whole lot of research done on controlling Ventenata. However, the rest of this article will summarize some of the research that does exist to help increase awareness of how the control strategies that have been attempted affect this grass.

It is important to understand the life cycle of the unde- sirable species you are trying to control because different control methods have varying degrees of effectiveness when applied at different maturity stages of the plant. Ger- mination of this winter annual begins in October while temperatures range between 47-84 degrees, and 50-95 percent seedling emergence will have occurred by the time winter dormancy is induced by temperature decreasing below 44 degrees. CONTINUED PAGE 32... www.orcattle.com | Oregon Cattleman

~ MEMBERSHIP IS WHAT YOU MAKE OF IT ~

A Message from OCA’s Membership Chair Rusty Inglis

Hello! For those of you that do not know me, my name is Rusty Inglis and I have been the chair of the Oregon Cattlemen’s Association’s membership committee for a little over six years now. Today, I want to address the importance of being a member of the Oregon Cattlemen’s Association (OCA) with the young ranchers out there who are the future of our organization. Not that I would not encourage the old grey hairs, or in my case, what gray hair that I have left, ranchers to become members. First, I want to thank Angela Faryan and Tyler Harris for the last two articles featuring young ranch couples that are OCA members as they are the next generation of OCA leaders.

Looking back to when I joined 35 plus years ago, yes, I can still remember that far back. I remember struggling to make a go of it with a small herd and no land of my own. One day, I read an article in the OCA magazine about ranchers needing a strong voice to help promote their industry. It convinced me to join the OCA and I have been an active member ever since, though it was not always easy. A few years ago, a young rancher came up to me and said he felt like OCA was just a good Ole’ boys club. I told him I felt the same way when I first joined. However, I kept coming to meetings, listening, and figured out how things worked. I started speaking up, giving my opinions, and guess what, they listen. Now I guess I could be considered in the class of the good O’ boys, but as your membership chair I am here to listen. You can talk to me in person, give me a call, text me or email me anytime. We may not always agree, but that is how life works; if you never express your opinion you will never be heard.

OCA works for you while you are staying on the ranch trying to make a living for your family. The organization goes to battle for you at the state and federal level every day to protect our way of life. The OCA has recently fought battles over the corporate activities tax, carbon tax, protecting our exempt use for our stock wells, fighting animal rights groups that want to see us gone, preserving our exemption to the personal property tax, I could go on and on. This is why we need you as members, so we can continue to fight the battles both at the state and federal levels, while you concentrate on making a living and providing a way of life we all love for your family. It takes a strong organization to fight those battles and it takes members to have one.

As a member, you can make OCA into whatever you want it to be. There are plenty of opportunities to volunteer and to stay involved. Some of us are retiring, but we will still be around to give you unsolicited advice. You are the future of this organization!

I hope what I have said today has convinced all of you young cattlemen and even the gray-haired ones, to continue to be members. You should talk to your friends and neighbors who are not members and encourage them to join. I ask you to stay engaged, participate in the organization as much as time and finances will allow, and remember OCA is your organization; you can make it whatever you want.

Well, I am fairly good at rambling on when it comes to an industry that is dear to my heart, so I am going to close for now. God bless all of you. •

The remaining seedlings will emerge during the month of May. These seedlings will undergo stem elongation through the month of May, achieve reproductive maturity during June and then will become senescent and brown by July. Some other considerations of this plant are that it is self-seeding, largely due to the twisted awn that allows it to self-bury. The twisted awn also helps it to latch on to animals, clothes, and hay bales, allowing it to easily become spread across the landscape. The seed has a germinable life of around three years, so control methods will have to be conducted for a minimum of three years to exhaust the seed bank.

A study performed by researchers at Oregon State University observed that cattle willingly graze Ventenata during the elongation and boot phases. Before elongation, cattle may demonstrate a higher preference for taller forages. Ventanata during the elongation phase actually provided adequate nutrition for the cows during that time, but nutrient quality and palatability sharply declines once the plant transitions into reproductive maturity. Despite the perceived usefulness of Ventenata during the elongation phase, grazing at this time actually resulted in a denser stand of Ventenata, thus furthering the issue. Perhaps there might be circumstances under which grazing could discourage Ventenata growth, but we do not have any evidence of that at this time.

In terms of herbicide use, the most effective time to apply herbicides to control Ventenata is in the fall, when the plant is in the seedling stage. Unpredictable weather conditions can make a fall application difficult, leaving a spring application as the alternative. Be careful with spring applications and consider the surrounding, actively growing, and desirable perennial forages may be very vulnerable to injury by herbicide at this time.

Active ingredients that have been tested to control Ventenata are imazapic, propoxicarbazone-sodium, sulfosulfuron, Flufenacet plus metribuzin, and Rimsulfuron. With the exception of flufenacet plus metribuzin and rimsulfuron, post-emergent applications were more effective than pre-emergent applications. Propoxycarbazone-sodium generally provided the least control across the board. Imazapic and sulfosulfuron caused noticeable injury to irrigated perennial forages like Smooth Brome and Orchardgrass when used to control Ventenata. Flufanacet plus Metribuzin and Rimsulfuron did not cause any noticeable injury to the irrigated perennial forages, but rimsulfuron did cause some injury to Intermediate Wheatgrass. All herbicide treatments caused little to no injury to Bluebunch Wheatgrass. Aside from the herbicides effectiveness in controlling Ventenata and the injury they may or may not cause to surrounding forages, the primary determining factor in choosing what active ingredient to use should be the restrictions that are expressed on the label.

Furthermore, it has been observed that herbicide treatments, in combination with strategic fertilizer applications, has proven to be the most effective in controlling Ventenata. It seems that Ventenata is not as effective in utilizing nitrogen as other forages, so nitrogen applications give the competitive advantage to the other surrounding forages. A fall fertilizer application of NPK or a spring application of N, in combination with a herbicide treatment has proven to be the most effective method in controlling Ventenata in irrigated pastures. Considering the aggressive nature of Ventenata, it seems inevitable that this will continue to be a growing concern on rangeland and pastures into the future. It is important that land managers are aware of the management issues/challenges that Ventenata presents. Consequently, it is vital that research identifies options to control this invasive annual grass in order to minimize or eliminate the spread to non-infested areas. •