Herbicide resistance is a term that carries a lot of weight in the agriculture industry. Whether you’re growing corn in Iowa or rice in Arkansas, weed control is a high priority. Resistance management is a key part of any herbicide program and we have come a long way since the release of Roundup Ready® Soybeans in 1996. Educational information like the Take Action Pesticide-Resistance Management Initiative, together with the release of new genetic platforms, help to fight herbicide resistance. What we know for a fact is that it takes a systems approach to manage weeds and herbicide resistance.

One of the newest options that fits into a lot of these systems is the LibertyLink® GT27™ genetic platform. This genetic package combines both glufosinate and glyphosate tolerance, along with HHPD – side of action (SOA) group 27 – herbicide tolerance. It’s important to note that as of January 2019, applications of HHPD herbicides were not yet approved in LibertyLink GT27 soybeans. The introduction of this herbicide tolerance package created a lot of questions; hopefully this article will help answer some of those questions for you and guide you to a successful weed-management program in 2019.

Can I use glufosinate and glyphosate in a tank mix?
Short Answer: Absolutely!

Long Answer: It’s not quite as simple as adding one or the other to your current herbicide spray mix and getting better weed control. There are some key factors to keep in mind before using this mix. First, these applications should be treated as Liberty applications with glyphosate as an additive.

This means the following guidelines should be implemented:

• Minimum 15 gal./A. (GPA) of total spray volume
• Minimum of 2 to 3 lbs. Ammonium Sulfate (AMS), preferably dry product
• Nozzle and pressure selection that generates medium to coarse spray droplets
• Maintain rates of both glufosinate and glyphosate that are labeled for control of the weed spectrum in your field(s)
• Make timely applications to weeds that are less than 4 to 6 in. tall

What is your recommendation for a weed control program using LibertyLink GT27 soybeans?
There are many options available in a LibertyLink GT27 soybean weed-management program. Below, you will find guidelines (or suggestions) for a three-pass system and a two-pass system. Always consult the applicable herbicide label before making any applications. You can also find more program recommendations in the 2019 Beck’s Recommended Herbicide Program for Soybeans brochure.

What level of control could I expect from this combination?
You can expect similar or better control than a current Liberty® post-emergence application. The glypohsate will help control a spectrum of weeds that Liberty may have struggled with prior to the tank mix, specifically some grass species as well as a few key broadleaf weeds such as Chenopodium album (Common Lambsquarters). However, the addition of glyphosate will not impact the control of glyphosate-tolerant volunteer corn. In this situation, the addition of Clethodim-containing product will be necessary.

In a world with an ever-increasing number and variety of herbicide-resistant weeds, having more herbicide options will never be a bad thing. As farmers, we must do our part and be good stewards of these programs to maximize their longevity. Taking necessary steps such as following herbicide labeled rates and rotating modes of action are a huge part of this process. At the end of the day, there are only so many ways we can kill a weed. As these herbicides become less effective, we start losing control options. My advice is to implement any of these effective weed-management systems to guarantee a weed-free future for generations to come.

Contact your local Beck’s representative or visit www.TakeActionOnWeeds.com for resources and more information.

~ Alex Long, CCA – Field Agronomist