Please do not spray dicamba late. I don’t care if you are using safened dicamba in corn or XtendiMax or Engenia in soybeans. When dicamba is sprayed late, the volatility issues are far more likely to cup soybean leaves than when dicamba is sprayed early in the season.

The first year that dicamba soybean applications led to leaf cupping on millions of acres in the U.S., I was racking my brain trying to figure out why we were seeing so many issues. You see, when I was a young agronomist more than 30 years ago, nearly every farmer I knew used Banvel, and I saw almost zero soybean leaf cupping.

The big difference between then and now, in my opinion, is the timing. Back then, most people tried to spray between spike and V2. After V2, unsafened dicamba is far more likely to hurt corn, but early spraying doesn’t seem to do much damage to yield. Anyway, in my area this spraying would typically occur in mid to late May.

If all dicamba applications were done by June 1, at least in my region, would we see any leaf cupping on soybeans? If we did, it would probably be very, very minor. The only way I know to stop the movement of dicamba is to not spray it. If you can wrap up your spraying extra early, that would be great. The question is what to spray later on instead of dicamba. Here are some options.

SOYBEANS

1. Liberty – If you have XtendFlex soybeans, you have the option of using Liberty. Sure, Liberty has been short in supply and the price is high, but this is a one-year issue. We are expecting supply to be great on Liberty and generic glufosinate next year. We are also expecting the price next year to be half (or less) compared to what it is today. Don’t let that worry you, though. Just because something could be half price next year does not mean it’s a bad investment this year. Liberty and generic glufosinate are now freeing up in terms of supply, so you should be able to find some somewhere. I know it’s hard to pull the trigger on a $25 to $35 investment for one application of Liberty just to control weeds, but if you don’t stop your weeds you know the yield penalty will be huge, not to mention the fact those weeds will go to seed and create issues on your farm for years to come.
2. Warrant Ultra (contains the a.i. from Warrant and Flexstar) or Anthem Maxx (contains the a.i. from Zidua and Cadet) – I love these premixes because they each contain a Group 15 and a PPO. The Group 15 (Warrant/Zidua) kills weeds only through residual activity, but it lasts a long time and helps a lot on tough weeds like kochia, waterhemp, Palmer pigweed, lambsquarters, black nightshade, and many more. The PPO (Flexstar/Cadet) has great burndown activity on most of those same weeds. Flexstar has lots of residual, which is why there is a 10-month rotational restriction to corn. Cadet has a little residual, but not enough to cause any carryover problems. You can combine other Group 15s and PPOs, but these two premixes are the most cost-effective.
3. Cobra/Phoenix – Phoenix is just Cobra plus a safener. Both have good activity on sclerotinia white mold, in addition to controlling or suppressing many broadleaf weeds. Our advice is to add 1.25 pounds of Solubor per acre to lessen the leaf burn. While we prefer to see Cobra or Phoenix sprayed before flowering, they are each labeled well after that point.
4. Roundup – Sure, there are a few weed species that are resistant to Roundup, but Roundup is still very effective on most weeds. Plus, many weeds are not resistant; they are just tolerant. If you use a high rate of Roundup and the weed is very small, you can often get control. When that same weed gets big, Roundup will no longer stop it.

None of us want to see tens of millions of acres of soybean leaves cupped up again this summer. If we do, it’s just that much sooner until dicamba is banned. While you think that might be the end of it, it won’t be. Keep in mind there are some loud voices in our country trying to stop us from farming the way we do today. While few in number, these people create political and legal challenges for us each and every day. Once dicamba is banned, and I have no doubt it will be if things continue like they have the last few years, they will come after something else. Even if all ag chemicals (many of which are very, very safe to our environment and human beings) are gone, they’ll try to get us to change something else.

What I’m saying is in my opinion we don’t need any more government regulation. If we want less (or at least no more) government intervention, we have to use our products and our resources more carefully. My advice is to stop spraying dicamba extra early. Pick one of the alternatives I’ve listed above or use something else. Even if you follow the label perfectly with any dicamba product, it can still pick up and move later on. You won’t give it the chance if you don’t spray it. Please use a non-dicamba herbicide if at all possible as we get later in the season.