By Brian Hefty – brian@agphd.com

“It was dry last fall, so my cheatgrass didn’t emerge.  I didn’t spray anything then because I didn’t see any cheat.  Now, I’m worried that I may have cheatgrass coming up this spring in my wheat.  What’s the best thing I can use?”  This was a question we had recently, so I thought I would share our response with you.

First of all, as I’m sure you are aware, cheatgrass or downy brome is much more easily controlled by applying a residual herbicide in the fall.  At that time, Maverick, Olympus, and PowerFlex are the most popular products.  Maverick has the most residual.  PowerFlex has the least carryover and shortest rotational restrictions to most crops.

In the spring, downy brome is usually more difficult to control.  However, if it popped up very late in the fall or really early this year, it probably won’t be as big as normal by the time you spray.  In the spring, PowerFlex can be used in winter wheat (it is NOT labeled for spring wheat), but there are other popular options.  GoldSky contains some PowerFlex (along with Starane and another broadleaf killer), but most importantly, it has about 3 times the safener that PowerFlex contains, which is why it can be used on spring wheat when PowerFlex can’t.

Rimfire, Rimfire Max, and Olympus Flex all contain low rates of Olympus, but we still worry about rotational restrictions and carryover, so be careful.

In terms of the normal foxtail/wild oat products like Axial, Discover, and Puma, they’re not good on cheat, but Everest 2.0 is.  Now that Everest 2.0 has been released, containing more crop safener than the old formulation, we find many farmers are using that product due to reduced leaf burn, good soil residual, and suppression on cheatgrass.

Here’s the other thing I’m always concerned about – antagonism.  If you mix grass and broadleaf herbicides in the same tank, it’s probable that your grass control will be reduced.  Either the products have a negative chemical interaction or the broadleaf herbicide burns the grass enough to prevent good uptake or translocation of the grass killer, leading to decreased performance.  What I’m saying is if you want the very best grass control, spray your grass product first and follow a week later with the broadleaf herbicide.  If you only have a few weeds in the field, tankmixing is fine, but if your field is loaded with weeds, consider this option to get the best bang for your buck.

Again, if your cheatgrass didn’t show up last fall, you should have fewer problems than normal stopping it this spring, but don’t take it for granted.  Cheatgrass is always hard to stop in the spring, but at least there are options.

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