As producers watch their weed emerge out in their fields, there’s also a common weed that they have to worry about many parts of the state. That weed is rye grass. Here to help us understand a little bit more about the plant, how to control is Joe Armstrong, a weed specialist here at OSU.
Let’s start with just a little identification of rye grass so we can tell it apart. There’s several grasses that farmers are fighting in wheat and identification is certainly the first step to pick the right herbicide and start controlling that weed. Winter rye grass is usually pretty, easy to tell because it got a very shiny leaf surface, almost kind of a waxy surface, which will help separate from a lot of the other grasses. It’s hairless generally, and the one identifying characteristic of these clasping oracles here is that there’s almost two little fingers that wrap around the stem. I’m connecting that leaf blade to the stem there.
So winter rye grass is probably one of the easiest grasses to identify but it’s something you have to kind of get down in there and check just to be sure what you have. What growers are fighting now is what we had thought, maybe was herbicide resistant ryegrass. Last year, as well as this fall here, we’ve done some screening here in the field with different herbicides and looking at multiple rye grass populations from around the state, to determine resistance to different types of herbicides, as well as it promotes of actions. What we found was about 70 percent of the samples that we looked at were resistant to the ALS inhibitor herbicides. So things like Powerflex, Osprey, Finesse pretty commonly used herbicides by most farmers that are not killing rye grass.
Now I should mention that 70% is kind of a biased number what we looked at was rye grass that was not controlled at the end of the season. Whether or not that was treated with the herbicide during the year or not, we didn’t know sometimes the history in that field. But we thought perhaps there was a resistance issue there.
What we’ve done is taken 200 ryegrass samples from around the state, basically all four corners of Oklahoma, planted them the lengthwise here in the field and then sprayed all of our herbicides across. So we’ve got ten different herbicide treatments as well as an untreated check where we can compare our control with. This is our untreated check here and you can see pretty healthy stand to ryegrass so that’s what we compare everything to.
This first plot here is looking at beyond herbicide some farmers might not be familiar with that. It’s an ALS inhibitor, it’s what’s used in Clearfield wheat. So in center field or oak field varieties, growers could spray beyond for grass control and also broadleaf control. You’ll see a couple of plants living here, some have been pretty well dinged up so it’s kind of difficult to tell. Maybe that the level of resistance that we have here. This is a pretty broad spectrum herbicide, so it will control a lot of weeds.
Tese two plots here are select and assure – and these are grass killer type products ACCase inhibitors, we call those and they’re using in winter canola, not in winter wheat. Growers may be familiar with these because it’s a grass killer product that you can spray on a broadleaf crop so they might use them in alfalfa or soybeans. Certainly no broadleaf activity so you want to throw something else in with your winter canola herbicide program besides this.
You can tell we’re getting excellent control of the rye grass here. There’s a few dead leaves around but for the most part it’s pretty non-existent. It’s taken them down and again this is a post emerge type product. But certainly a good option for ryegrass control if you can rotate to winter canola.
Another is glyphosate or we looked at a roundup brand product. This one’s kind of tricky you can see plenty of dead plants here. But you see a lot of green ones too. That’s the problem with roundup, sometimes it doesn’t have any soil activity so once you spray it, that’s the control you’re going to get. It’s strictly a post emerge product so this new growth here is all things I’ve germinated with this rain and warm weather we’ve had the last couple weeks.
If rye grass is your main weed, you’re gonna want to look at something else, a different mode of action. This is the other mode of action that growers would want to use. These two plots are again ACCase inhibitors, Axial XL and Hoelon. These are used specifically for wheat. It’s kind of a unique chemical where you can spray a grass killer in a grass crop.
But what we get here is excellent control rye grass. You can see a lot of carcasses there, totally fried leaves, but again no broadleaf activity. And the other issue with these two products is that they don’t control any of the other grass weeds. They’re primarily for rye grass and wild oats. If you have cheat or any of the brooms, you know you’re gonna have to look at another something product so these won’t work for those, but they seem to do a really good job.