News > CFE News Folder > Weeds & Field Update

Weeds & Field Update

Jun 10, 2021

By Agronomy Sales Manager, Terry Aukes

What a difference a couple warm weeks make! The crop is progressing along and so are the weeds. I wanted to take some time and share what we at CFE have been seeing in customers fields. Overall, pre-emerge herbicides have been working great on what limited moisture we received, but considering most pre-emerge applications were mid to late April, and we are early June now, these herbicides are exhausted and running out of steam. We expect a good 3 weeks of strong weed control from pre-emerge applications and we are pushing 6-7 weeks now. I wanted to give a strong recommendation to take a hard look at the post application herbicide program and consider adding the next layered residual for grass and broadleaf control. Products such as Dual, Harness, Outlook, Triple Flex, Surestart, Surpass, Warrant are just a few to consider adding. While we cannot predict the future but if it does stay dry and crop canopy is slower having an extended residual to carry us to crop canopy will be important.  For whatever reason we are seeing more wholly cupgrass than normal. Wholly cupgrass is easily controlled by Roundup but again, another reason to consider the added residual herbicide.

With the dryness we have experienced this spring we have noticed considerable amount of no till corn and soybeans than other years. This has resulted in tweaked chemical programs and the burndowns are working well. If you are one that did no till pay attention to watch for marestail.  This is a typical no till weed and can be difficult to control. Careful consideration is needed as straight Roundup is not all that great in controlling marestail. A trend we see in 2020 and again in 2021, growers are planting soybeans earlier and earlier and the data supports this trend but just keep in mind we are stretching the length of control we are asking of our burndowns. Keep a careful eye on these fields as our post applications may have to be applied sooner versus later and again, I stress the importance of including a layered residual for the same reasons in corn to reach crop canopy weed free.

I would like to comment we are seeing quite a bit of Fomesafen carryover symptoms in corn from the herbicide application made on soybeans last year. We attribute seeing elevated carryover due to lack of moisture already dating back to last summer. Timing can also be a critical factor as we try to make the cutoff of July 1 and not apply Fomesafen after this date due to carryover concerns. Common Fomesafen herbicides used are Flexstar, Flexstar GT, and Warrant Ultra and generally with good growing conditions corn will come out of it. An exception might be where there are point rows and application area was doubled up for some reason can be particularly hard on corn. Soil organic matter and ph can also have an influence in carry over but it is just something to watch for if you have applied any of these products.

My last comment on weed and field updates is please stay in communication with your CFE agronomist. If we continue this hot and dry pattern, adjuvant loads will have to be evaluated to minimize crop response during high heat but also weeds may become hardened and more difficult to kill. Having a fine-tuned chemical program before you spray is much easier than dealing with the repercussions of weeds not dieing and trying to respray. Have a safe spring!

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