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The NDSU Extension weekly podcast In the Pod: Soybean Updates delivers timely insights and expert advice on soybean production.
You're listening to In The Pod, soybean updates, a weekly trek into the latest soybean information from NDSU Extension. Even though fall is in the air, weed control in soybean continues. According to Joe Ikley, NDSU Extension weed control specialist, soybean weed management extends into the next season. Joe, have you been getting many questions about preharvest applications?
Joe Ikley:Yeah. So probably more interest this year than the previous several years about preharvest application, in soybean, and particularly for the purpose of a desiccation. We're having a lot of fields out there that are pretty uneven in their maturity, and so that's when folks wanna use a herbicide to kind of even out the crop and make it dry down, really increase the efficiency of the harvest operation. So a lot of questions about that this year, and there's only a few products that we can use in soybean. The primary ones will be carfentrazone, which is AIM, Sharpen, Paraquat, and then there's a product called Defol on the market. So those are the four that are gonna desiccate the soybean crop. And the important notes there, you definitely need to make sure the timing is right so the soybean crop is mature enough to trigger that application, and then follow the preharvest interval, which is usually about seven days or less. As far as effectiveness, we usually see those group 14 herbicides like Aim and Sharpen are the quickest at drying down the crop. Gramoxone can be okay, but the rate that we use in soybean is much lower than folks might expect for something like dry bean or sunflower. The expectation with Gramoxone there is a lower use rate in soybean. So that's really the number one question at this point in time I've been getting within soybean.
Bruce Sundeen:Joe, have you been getting many questions about preharvest applications?
Joe Ikley:That's gonna be the next step, and it can already be occurring in the crops that we're going to be planting into soybean next year. So a lot of wheat stubble out there. Canola has been coming off at a pretty decent clip. So any of these fields going into soybean next year, especially for no till, we need to start thinking about some herbicide applications in the fall. And so there's a couple of different key timings, and I don't expect people to go out and spray two or three times, so I'd say pick your driver weed in that field. Particularly as we get further west, winter annual weeds like horseweed or narrowleaf hawk's beard can be very difficult. They germinate about this time of year, and they're gonna overwinter and be much more difficult to kill in the spring. Something as cheap and easy as glyphosate in two four d will take care of those winter annuals. That can really occur about any time now they're up and and actively growing. Perennials are the other problem, so think Canada thistle and foxtail barley. Best time for us to make an application to those is usually sometime in October. As long as the ground isn't frozen, October tends to be the best time. Something as simple as glyphosate is all you really need for those at this time of year. The other thing we talk about with fall applications is residual lasting into next spring, particularly targeting Kochia. This timing, we want you to make the application as late as possible in the fall, so right before the ground freezes if we can. We can't make an application on the frozen ground kind of right before that freeze up, whether that's October, November, December, you know, it kind of fluctuates each year, but typically focusing on late October for that application. Historically, we've looked at things like flumioxazin or valor. We do have resistance to that now in many areas across the state, so that's an important thing to know your resistance in your field if you can. Otherwise, we've looking at things like metribuzin, pyroxasulfone, which you can get in the form of Zidua or Anthem. Those have given us some pretty decent results in that fall application catching that early flush of kochia to help out next spring for kochia management.
Bruce Sundeen:What about other fall applications?
Joe Ikley:To find this information, we we have some data available on our NDSU weed science website. So many of these data points are in presentations from past wild world of weeds. So we've got PDFs on there. I just Google or search engine of choice, NDSU wild world of weeds. You can get PDFs there. The last two years, we do have presentations recorded and up on the NDSU Extension YouTube page. So usually folks like myself or Brian Jenks may be talking about these fall applications, Kirk Howlett as well. Look for some of that information there. It's probably the best source.
Bruce Sundeen:Thanks, Joe. Our guest has been Joe Ikley, NDSU Extension weed control specialist. You're listening to In The Pod, soybean updates, a weekly trek into the latest soybean information from NDSU Extension supported by the North Dakota Soybean Council.