By Brian Hefty

Last month I wrote about XtendiMax and Engenia in Xtend soybeans and cotton, but since this is the first year in history you have had the chance to legally spray dicamba over the top of these crops, I figured you would probably like to hear more about it.

I encourage you to go to and to learn more about the tankmix partners, spray adjuvants, and spray nozzles that are currently approved.  The approval process is ongoing, and more things are being added all the time.  Perhaps the two most important things to know are DO NOT USE AMS, but DO USE DRIFT REDUCTION SPRAY NOZZLES.

Here are a few additional pieces of information about XtendiMax and Engenia I didn’t mention last month.

  1. There are rebates that can really cheapen up your net cost.  If you use name brand Roundup and at least one of the many pre-emerge herbicides in Roundup Ready Plus, XtendiMax is probably the least expensive option.  If you use a lot of different BASF products, Engenia could be cheaper.  So far, most of the farmers we work with are going XtendiMax, primarily due to price.  Both products are effective with very little volatility risk.
  2. There is residual with dicamba.  When using the full, labeled rate of XtendiMax or Engenia, it is likely you will get some broadleaf activity for one to two weeks afterwards.  The contact activity is better than the residual, but still, some residual is better than none.  That’s something you gain with dicamba compared to Roundup.
  3. In terms of weed height, dicamba might be able to take down some big weeds, but for best control and top yields, we strongly encourage you to spray when weeds are 4 inches tall or less.
  4. Slow down.  You should be spraying at a pace no faster than 15 mph, and we prefer a slower speed than that.
  5. A drift reduction agent (or drift retardant) may be used to reduce off-target movement.  However, make sure you don’t over-do it.  Like we always say with drift retardants, keep the rate low and jar test first.  The last thing you want in your tank is sludge.  While that doesn’t happen often, what’s more likely to occur is a bad spray pattern.  You need a good spray pattern and good coverage to achieve the weed control you are looking for.
  6. XtendiMax and Engenia aren’t just for Xtend crops.  They can both be used in corn, non-crop areas, and a host of other situations.  For example, around our fencelines and ditches we are now spraying XtendiMax instead of old Clarity or 2,4-D.  There is way less drift, and the effectiveness on Roundup-resistant weeds is great.  Yes, generic dicamba is cheap, but for only a little bit more money you will have far less off-target movement.  Think of it this way.  If you have one drift issue onto your sensitive crop or your neighbor’s, that little amount you saved going with a highly volatile, 50-year old herbicide is going to seem pretty insignificant.
  7. Some farmers have expressed to me their apprehension about using dicamba post-emerge in soybeans.  It’s not much different than when Roundup beans first came out.  Some people were nervous, but look at what happened over time.  We believe that in many pockets around the country, by next year 90% of all the soybeans planted will be Xtend.  This is primarily due to the spread of resistant weeds.  How are you going to kill marestail and kochia in soybeans without dicamba?  What happens if you don’t get three pre-emerge herbicides down?  What are you going to do with the millions of waterhemp or Palmer pigweed plants that could end up in your field at some point?  I’m not saying Xtend is the greatest thing ever, but I am saying it’s nice to have another great option for weed control when all else fails.  Here’s the best part of the whole thing.  In our trials in several states last year, Xtend beans outyielded Roundup 2 beans by one to two bushels.