By Brian Hefty

Xtendimax is now labeled for use in Roundup Ready 2 Xtend Soybeans!  I know.  You are probably wondering what took so long.  I am, too, but let’s focus on what to do with this technology now that it’s here.  Below are the top 10 things I want you to consider this spring when using Xtendimax.

  1. Get your sprayer set up before spring with the right spray nozzles.  You will need a low drift spray nozzle.  By the time you read this article, there may be several nozzles approved.  Just check with your retailer or equipment dealer.
  2. Follow the buffer requirements.  We were concerned the Xtendimax label was going to be very restrictive, but it’s not.  Sure, there is a downwind buffer to sensitive crops, but that’s just common sense.  Would you really spray something on your neighbor’s crop when the wind is blowing that direction?  Of course not.
  3. While Xtendimax specifically spells out some things on the label, almost all of it applies to spraying all herbicides.  For example, you are supposed to spray when the wind is relatively calm, keeping your sprayer speed and your boom height down.  Use at least 10 gallons of water (that applies to almost every other herbicide except glyphosate).  Use a labeled rate to control a labeled weed at a labeled height.  Just like with the buffer requirements, I look at all this stuff as common sense, as they are practices most farmers already follow.
  4. Dicamba doesn’t kill big weeds.  Don’t get me wrong here.  Dicamba is an awesome weed-killer.  However, like almost all other herbicides, the smaller the weed, the better the control.  If you’re thinking of going one-pass with dicamba at R1 in soybeans, allowing the weeds to get a foot tall, you likely won’t be happy with the control.  Remember back to the days when you loved dicamba’s weed control in corn.  You were spraying when the corn was 2 to 4 inches tall, and the weeds were small.
  5. Dicamba doesn’t work well when the weather is cold.  If you think you can spray dicamba or almost any other herbicide when the daytime high is in the 50’s, that’s not going to work.  Ideally, we’d like to see the daytime temp in the 70’s or higher to maximize control.
  6. Don’t use AMS.  We love ammonium sulfate with Roundup, but apparently with dicamba it increases volatility.  There are new “dicamba-approved” adjuvants that you will need to use this spring.
  7. Check the tankmix partners before spraying.  Currently the EPA is testing thousands of different adjuvants and tankmix partners for use with Xtendimax.  We expect the label to be continually updated with products safe to use in combination with dicamba in soybeans.  While I don’t have many answers for you today, this should all be pretty clear by the time you need to spray.
  8. Dicamba has residual.  Our old saying has been, “You only have residual with dicamba until the first rain”, but still, there is some residual.  Roundup, of course, has no residual.
  9. Consider spraying your fencelines, ditches, and non-crop areas with dicamba.  If you’ve got a crop that’s tolerant to dicamba, you don’t have to worry as much about the volatility characteristics with Clarity and Banvel when spraying those according to their labels.  For example, while it may have been labeled to spray your road ditches with dicamba in the past, you never did it in-season because you were worried about product movement into your sensitive soybean field.  Now you can better control all those weeds in your non-crop areas, leading to lower weed populations in your crop ground.
  10. Use a couple pre-emerge herbicide modes of action.  In order to get early season weed control, good soil residual, and to help prevent weed resistance, we strongly encourage you to apply a good pre-emerge herbicide package.  In Xtend beans, when you use Xtendimax and Roundup there are big rebates available on products including the Authority brands and Fierce.  It’s also very possible you may be able to get by with one shot of dicamba post-emerge instead of two when you use the right pre products early in the season.