New Dicamba and 2,4-D Herbicides: The Basics of the Product Usage

As we head into this season of pesticide re-certification, many have asked about the guidelines for the new herbicide resistant crop systems created by Monsanto and Dow using dicamba and 2,4-D formulations. Let’s take a quick look at the basics of the new products and how we can use them the best.

Concerns with both products rest on the fact that they will be sprayed over the crop later in the growing season and be more susceptible to harm of non-target sensitive crops. This includes your neighbor’s soybeans that may not be resistant to this formulation.

Drift is the biggest complaint to the Ohio Department of Agriculture each year, but they have clear rules about drift! “No person shall apply pesticide to an area or crop in such a manner or such a time that adjacent crops, pasture land, water or other area will be damaged or contaminated.” So how do we go about preventing spray drift with this new system?

1. Be sure you have the traits you think you do before spraying. In other words, know what varieties you’ve planted in each field and make sure your workers know the same. Also, now is a good time to use that good neighbor policy and make sure you know what they might have planted too, especially if it is up against your field.
2. Use only herbicides registered for in-crop use! Xtendimax can be used legally in-crop on Xtend beans. Other formulations are forthcoming. While dicamba and 2,4-D come from the same “parent acid” not all formulas are the same. The low volatility is in the chemistry of the product; other formulations will still have the high volatility.
3. Follow tank mix restrictions. Xtendimax has no tank mix partners approved yet and Enlist Duo has some (enlisttankmix.com). If you were to add ammonium sulfate to Xtendimax you would ruin the “vapor grip” technology and no longer have low volatility.
4. Use only the required nozzles and operating pressures. Enlist Duo has 23 approved nozzles with psi ratings. Xtendimax only has TeeJet TTI 11004 with a psi of 63 max. More are to come, but this is all for now. To use either one of these products legally, you may need to replace all your nozzles.
5. Observe wind speed restrictions on the label. Optimum wind speed is 3-10mph. Both formulations prohibit spraying above 15mph and Monsanto prohibits spraying below 3mph. Less than 3mph most likely indicates a temperature inversion. Check your wind speed with monitoring equipment at your location not just by the local weather station. It is going to vary according to your distance from that station.
6. Know your wind direction. You want to make sure the wind is blowing away from sensitive or non-formulated crops. The label says DO NOT APPLY when wind is blowing toward adjacent sensitive crops… Do not means you cannot do it legally. The Applicator Must: consult sensitive crop registries to identify crops located near application site.
7. Be aware of sensitive area nearby. Know your surroundings, understand your proximity to sensitive areas. Identify habitat for endangered or threatened species. This is not a common item that all are aware of.
8. Maintain required downwind buffer zones to sensitive areas.
   1. Enlist Duo – 30 feet
   2. Xtendimax low rate – 110 feet
   3. Xtendimax high rate – 220 feet
9. Maximum ground speed of 15mph. Even if the weather is threatening and you may want to get finished sooner, ground speed influences drift, boom stability and turbulence.
10. Use the lowest effective boom height. Do not exceed 24” above target or crop canopy.
11. Other restrictions on the label.
    1. No aerial application
    2. Crop growth stage limitations
    3. Maximum and minimum use rates
    4. Minimum spray volume 10gpa
    5. No rainfall within 24 hours (Xtendimax)
12. Strictly follow the label and your technology agreement. To use Xtendimax in-crop, you MUST have the supplemental label in your possession to legally use the product in-crop.

Let’s get this growing season off to a great start by making sure we read the labels, record what varieties and pesticides are in each field, talk with our neighbors to know what they have and make sure you are using the products and equipment in the safest and best method.

*Information obtained from the Ohio State University Pesticide Safety Education Program