Enlist technology needed against pigweed, waterhemp

Enlist technology needed against pigweed, waterhemp

When I was in graduate school at Mississippi State University, one of the coolest classes I took was called plant molecular engineering. In that class we got to “fire” a gene gun. That is, we went through the process of creating a (by definition) genetically modified organism. In reality (sorry, Dr. Reichert) it was actually kind of anti-climactic. A puff of air that inserted one bit of DNA into a callus tissue, from which a plant could be regenerated that included the new DNA. But it was still cool.

Maybe this is one reason that I do not fear and, in fact, support the use of GMOs in agriculture’s efforts to feed the world. In addition, because I am on the front line of fighting one front — weed competition and resistance — I see the benefits.

The latest news that the EPA has pulled back the registration of Dow’s new weed control technology Enlist, which grants tolerance to both 2, 4-D and glufosinate herbicides, is very disheartening. This is especially true as more and more counties in Arkansas have now reported either confirmed or highly suspicious populations of pigweed that are resistant to not only glyphosate, but also to the PPO family of chemistry, including post and to a lesser degree pre or soil-applied applications of these products. PPO-resistant waterhemp is also taking over the Midwest. Both 2, 4-D and glufosinate (the active ingredient in Liberty herbicide) are effective on PPO-resistant pigweed and waterhemp.

I fear that this pullback has less to do with science and more to do with legal efforts of certain special interest groups.

I fear also what this means for future GMO registrations as they come up, including Monsanto’s Xtend technology, which bestows tolerance to dicamba herbicide to crops, and to the registration of any new pesticide for that matter.

I know that it sounds good to talk about sustainable agriculture and organically grown, pesticide-free, non-GMO, etc. These niche systems have a place, but they are, in fact, the ones that are not sustainable and cannot alone feed the world. I hope and request that anyone who reads this article study this issue hard before making a decision on where you stand. Do not rely on pop science and the media!

Palmer pigweed is a serious problem for us in Arkansas agriculture. It is a threat to soybean production in particular. The pigweed currently in my greenhouse appears to be resistant to Roundup, the ALS chemistry (Classic/Scepter), the DNAs (Prowl/Treflan), and now the PPOs (Valor, Flexstar).

For these growers, all that is left is to rotate crops or grow LibertyLink soybeans. Even with the Liberty technology I recommend a residual program up front that includes Dual or Zidua plus metribuzin, two of the only modes of action left to which pigweed is still susceptible. If we do not use these herbicides in conjunction with Liberty, Liberty-resistant pigweed is next.

I am not biased — unless you count looking out for the needs of farmers. I have serious concerns about how farmers are going to use new GMO technology — for example, how to prevent drift and the further development of resistance — but not the technology itself.

Enlist, Xtend and HPPD tolerance are the newest technologies that we have for soybean weed control and they are all GMO-based. We are not looking at any new conventional herbicides at this time, and new ones are a long way off at best.

The companies have invested millions in these current GMO technologies. This means we must get by with what we have, and use these technologies until new ones can be developed.

I hate leaving perfectly good tools in the tool bag unless there is a good valid reason why we should do so. The herbicides 2,4-D and dicamba are not perfect and like all pesticides they come with some risks, but the fact is we are going to need new technology soon. If not this technology, then what?

You can follow me on twitter at @BobScottWeedDr

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