Listen to this week’s KTIC Radio Extension Corner:
This is Aaron Nygren, your local agronomist with Nebraska Extension in Colfax, Cuming, and Stanton counties. This week let’s talk about what to do if weather or field conditions prevented you from getting a pre-emergence herbicide applied before your crop emerged.
Last week Keith Jarvi talked about the importance of herbicide site groupings to manage herbicide resistance. A key component to increase the number of herbicide site groupings in your program is the use of pre-emerge residual herbicides. Under ideal conditions, most of the time we plan on applying these products before crop emergence. However, weather or field conditions often prevent this from happening.
If you find yourself in this situation, first off, be sure to verify that the product you were planning on applying is labeled for application after crop emergence. If not, you will need to switch your herbicide plan. While eliminating the residual product and going with a total post emerge, non-residual program is an option, for both overall weed control and resistance management, our recommendation is to stick with the residual program.
For corn, there are lots of options for residual herbicides that can be applied after crop emergence, with products coming from site groups 2, 3, 5, 15, and 27. A few examples of commonly used products are atrazine, Balance Flexx, Breakfree, Dual II Magnum, Harness Extra, Corvus, Lumax, Lexar, Outlook, Prowl H20, TripleFLEX, or Keystone. For a more complete list of products that can be applied after crop emergence, see the 2017 Guide for Weed, Disease, and Insect Management in Nebraska (EC 130) published by Nebraska Extension (which is available for purchase online for $15.00 or if you stop by any of your local extension offices) or visit the croptechcafe.org website.
When applying herbicides after crop emergence, products may or may not have foliar activity so a tank mix partner to kill emerged weeds might be needed. While it may be tempting to save a pass, try to avoid mixing herbicide with UAN for crop safety after crop emergence.
While corn has lots of labeled options, the number of soybean residual products that can be applied after emergence is much more limited with products coming from groups 2 and 15. A few examples are Anthem MAXX, Dual II Magnum, FirstRate, Outlook, Prefix, Pursuit, Warrant, Warrant Ultra, and Zidua.
Always read herbicide labels before applying in the field to double check that the herbicide can be applied after emergence. In addition, be sure to check growth stage restrictions, tank mix partners, and weed size.
To listen to this radio message again or to get more information, visit our local website at croptechcafe.org or give me a call at 352-3821. This is Aaron Nygren, your local agronomist for Nebraska Extension on KTIC radio.