Incoming Herbicide Resistant Crops: What’s Next
Posted: March 4, 2014
Enlist corn and E3 soybean (Dow AgroSciences) are a new lineup of genetically modified crops in the Enlist Weed Control System. Enlist corn will be combined with SmartStax and thus be resistant to glyphosate, glufosinate (Liberty 280), and post-grass (FOP) herbicides (e.g., Assure II and Fusilade, but not Select and Poast) and have a greater tolerance to 2,4-D. Enlist E3 soybean will be resistant to glyphosate, 2,4-D, and glufosinate. (E3 refers to a single-event molecular stack containing three traits vs. traits that are stacked individually.) Also a new 2,4-D formulation (choline) is being developed that will offer ultra-low volatility, reduced drift, decreased odor, and improved handling (referred to as Colex-D Technology). The first herbicide premix to emerge will be Enlist Duo which is a combination of 2,4-D choline plus glyphosate for use over Enlist crops; other products will likely follow. No other 2,4-D formulations are expected to be labeled for use over-the-top on Enlist crops. Once approved, corn and soybean varieties are expected by 2015. An Environmental Impact Survey (EIS) was recently completed on Enlist crops and now a public comment phase is occurring.
Roundup Ready 2 Xtend soybeans (dicamba-tolerant) are being developed by Monsanto and BASF to allow pre or post applications of dicamba (active ingredient in Clarity, Banvel, etc.) on soybeans. These varieties will be stacked with the Roundup Ready trait. In addition, BASF is developing a new, next-generation, dicamba-containing formulation for use in this system. It is a BAPMA, polyamine salt formulation and is 40% less volatile than Clarity; it will be called Engenia. Monsanto will have its own dicamba-containing products (DGA-salt, the same salt in Clarity) called Extendimax and Roundup Xtend that includes “VaporGrip” technology, a special adjuvant to help reduce drift. Once approved, this system will likely be available by 2015 or 2016. An Environmental Impact Survey (EIS) is currently in effect for these soybeans.
In general, there are some benefits and risks associated with Enlist and Roundup Ready Xtend crop technologies. Overall, we can expect to see better annual and perennial broadleaf weed control in soybeans. Also these traits will offer some protection from drift and spray tank contamination. However, off-site movement of 2,4-D and dicamba to sensitive non-target plants remains a concern. In a diverse landscape like Pennsylvania, this will be more of a concern than perhaps for our neighbors to the west. These companies are hosting field day training sessions (Enlist Ahead, RR Learning Xperience Plots, On Target Application Academy) to showcase special stewardship guidelines on nozzle type, spray boom height, ground speed, wind speed, among other management issues.
HPPD and MGI-tolerant soybeans are being developed by Bayer CropScience and Syngenta to allow the use of in-crop applications of HPPD-inhibitor herbicides as well as glufosinate and glyphosate. MGI stands for: Mesotrione (Callisto); Glufosinate (Liberty 280); and Isoxaflutole (Balance). Balance GT soybeans were approved by FDA and USDA in August 2013 but specific herbicide products for use in this system have yet to be announced. This system is expected to be launched by 2015 or later.