Source: Dr. Alan York, NCSU COOPERATIVE EXTENSION SERVICE, 11/15/16

Monsanto received EPA registration for XtendiMax with Vapor Grip Technology to be used on XtendFlex cotton and Roundup Ready 2 Xtend soybeans on November 9, 2016. Comments below pertain specifically to cotton.

The XtendiMax label for cotton can be found at: https://www.regulations.gov/contentStreamer?documentId=EPA-HQ-OPP-2016-0187-0958&disposition=attachment&contentType=pdf
This was a conditional registration, or a time-limited registration, and will expire on November 9, 2018 unless the EPA determines before that date that off-target incidents are not occurring at unacceptable frequencies. At that scheduled expiration date, the EPA can amend the label in any way they deem necessary, and they can extend registration to no later than November 9, 2021. The registration will automatically expire on November 9, 2021 unless the EPA determines prior to that data that herbicide resistance to dicamba is not occurring at unacceptable frequencies and that off-target incidents are not occurring at unacceptable frequencies. In other words, if we have a lot of off-target issues or if resistance to dicamba becomes an issue, we could lose the registration.

XtendiMax is a single active ingredient product. It contains only dicamba, as the diglycolamine salt, and Vapor Grip. Vapor Grip is a proprietary ingredient; Monsanto will not disclose what it is although they have explained the mechanism by which it works. Vapor Grip basically keeps the dicamba in a less volatile state.

Dicamba is commercially available primarily as two salts although a few products containing dicamba acid are available. The dimethylamine salt (DMA salt) is what is in Banvel and some generic products, and of course Banvel has a reputation for being volatile. The other salt is a diglycolamine salt (DGA salt), which is in Clarity and some generics. Dicamba DGA salt is much less volatile than dicamba DMA salt. The Vapor Grip technology further reduces volatility.

BASF is anticipating registration before the 2017 use season for Engenia. Engenia contains the BAPMA salt of dicamba, and company data show that the BAPMA salt is less volatile than the DGA salt. I am unaware of any data on a direct comparison of volatility of XtendiMax with Vapor Grip and Engenia. And, there is a possibility that Monsanto will receive registration for Roundup Xtend before the 2017 growing season. Roundup Xtend will contain glyphosate, dicamba, and Vapor Grip.

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