By Brian Hefty
I got a letter from the State of South Dakota the other day saying our state had made ALL straight dicamba products restricted use. Please check with your state about this! I just want to make sure you are following the law, because even for me, when I work with this stuff every day, that letter caught me by surprise. By the way, from everything I know about this new South Dakota law, Status and other premixes that contain low levels of dicamba are not restricted use, but Banvel, Clarity, and the straight generics ARE restricted use now in our state.
With that out of the way, let’s talk about the best post grass options in corn this year. For post grass, there is Roundup or Liberty if you have those traits. In conventional corn, there’s Accent Q. Those are your choices – pretty simple. Let’s move on to broadleaves.
For post broadleaf control in corn, you really only have three choices: Status, HPPD, or dicamba. Yes, you can use some of the combo products I will talk about below, but first, here’s what you need to know about the top three.
Best Roundup Tankmix Partners:
- HPPD – The HPPDs (Laudis, Impact, Callisto, etc.) have gotten so inexpensive, that you will undoubtedly be tempted to use them both pre and post. Here are my two huge concerns with that: resistance and carryover. Personally, I don’t even like to use a full rate of an HPPD on our farm because we’ve seen carryover if there is any overlap at all. If you are growing continuous corn, this is no big deal. If you want to rotate back to soybeans or almost any other crop, my advice is use an HPPD once per season. That’s it. Overuse of HPPDs could also lead to weed resistance. We have one report already with waterhemp in Nebraska. Our advice is continue to rotate modes of action and use multiple EFFECTIVE modes of action as often as possible. That said, our number one piece of advice if you haven’t used an HPPD pre is to spray an HPPD post if it fits your rotation and weed spectrum. It is too inexpensive and effective to pass up in most cases.
- Status (Diflufenzopyr plus a little dicamba) – This is my favorite post-emerge product in corn because of its broad weed spectrum. Status can control almost any broadleaf better than any other herbicide. It has some residual, but not so much that carryover will ever be an issue. Status is also great because of its corn safener. Even though the label allows you to spray bigger corn due to the safener, we still like to see Status applied by V5. The biggest downfall to Status is it is way higher-priced than straight dicamba or an HPPD.
- Dicamba – Banvel and Clarity have been out forever, and they still work pretty well on most weeds. Sure, they’re not as good as Status, but they are cheaper. The two things people have really not cared for with Banvel and Clarity over the years have been drift and crop injury. If you are going to mix Banvel or Clarity with Roundup, we suggest you spray by V2 if at all possible to practically eliminate crop injury risk. There is also DiFlexx, which is Clarity plus a safener if you want to spray after V2.
Best One-Pass Early Post Products:
- Acuron Flexi – This is a newer combination of Callisto, bicyclopyrone (a new HPPD), and Dual. Adding the second HPPD seems to broaden the weed spectrum a little bit, as we are seeing better results on wild buckwheat, for example. Like each of the other products in this category, Acuron Flexi can be used pre or early post. Most people will mix a glyphosate and occasionally atrazine with Acuron Flexi, but it could be used without glyphosate if you have almost no emerged grass.
- Resicore – This product contains the active ingredients found in Surpass (same as Harness), Stinger, and Callisto. Having 3 modes of action with broadleaf activity is nice, but just like with Acuron Flexi, it struggles with emerged grass and could use a glyphosate tankmix partner if that’s a concern.
- TripleFLEX – This combination of Harness, Stinger, and Python has been out for quite a few years. It is the cheapest of all these options, but Python is an ALS herbicide, so that component won’t help you on ALS-resistant weeds. On most Roundup-resistant weeds, the other three options listed here are better, but they are also more expensive.
- Halex GT – This product has also been out for several years. Its big advantage is it already contains glyphosate, to go along with Callisto (mesotrione) and Dual. While Halex is still an excellent herbicide on most weeds in an early post situation, it now has good competition from Resicore and Acuron Flexi, as they each contain mesotrione, too.
Which product would I pick? It all depends on your weed spectrum, weed pressure, and what I used pre-emerge. All 7 of the products (or product categories) I listed above are sound, and I would feel comfortable applying any of them on my farm using the guidelines I laid out above. One last note, FMC has a couple popular herbicides I didn’t list here: Anthem Maxx (Cadet plus a.i. found in Zidua) and Solstice (Cadet plus a.i. found in Callisto). Both of these products are effective and priced right. My only concern is with Cadet on corn, as that seems to give some leaf burn when the corn leaves are wet. You can avoid problems by spraying when there is no dew or rain on the corn leaves.