Palmer pigweed threatens glyphosate technology
Oct 27, 2006 9:42 AM,
By Ford L. Baldwin
Practical Weed Consultants, LLC
Palmer pigweed is a threat to change the way we farm unless we get smarter in the way we utilize our Roundup Ready technology.
There was an excellent article recently in an Arkansas newspaper discussing biotechnology and the blessing it has been. The farmer quoted in the article is an excellent farmer I have known most of my career. The gist of the article was that Roundup Ready crops had kept him in business.
He talked about how, through the tremendous improvement in efficiency afforded by the technology, he could farm 4,000 acres with the same amount of labor his dad used to farm 800 acres.
He supplied some specifics for the point I have been trying to make — that we did much more than just switch herbicides when Roundup Ready came along. Most farmers completely changed the way they farm soybeans and cotton.
The article was excellent, but there was no mention of any threats to the technology or what would happen if the technology were to be lost.
It should be obvious, however, that if we changed the entire way we farm with the technology, it will be lost if the technology is rendered ineffective.
In my opinion, Palmer pigweed has the potential to do just that if we continue to overuse the Roundup Ready technology. There could also be other weeds with the same potential.
I predicted Palmer pigweed would be the first major weed to develop resistance to glyphosate. That honor went to marestail. However, I believe that glyphosate-resistant Palmer pigweed is the first real threat to the technology.
Folks in Georgia are already getting the graduate course. My boys kicked me out of the Delta Weed Workers’ annual get-together when I retired from my university job, because it remains a university, scientist-only meeting.
However, my spies tell me that the group invited Stanley Culpepper from the University of Georgia to give an update on the situation with glyphosate-resistant Palmer pigweed. He apparently reported they have thrown the kitchen sink at some pigweeds and had to disk up the cotton. More specific information on that subject will be the topic for a later article.
Apparently, the resistant Palmer pigweeds in Georgia are tougher than the ones in Arkansas. The ones tested to date in Arkansas will at minimum turn yellow for a while when sprayed… if that is any consolation. Apparently, the biotype in Georgia shows no response from an application.
Palmer pigweed resistance is a threat to the technology for at least two reasons.
First, we had already failed to control it with all of the available herbicides before Roundup Ready came along. Therefore, switching herbicides is not going to be a simple answer.
I think the LibertyLink technology has potential to help, but the technology has to be in a range of acceptable varieties to the grower. Beyond this, herbicide answers alone are going to be hard to come by.
Another reason it is a threat is because it is such a prolific seed producer. An individual plant is capable of producing around 250,000 seeds. It does not take much imagination to see that when resistance develops in just one plant in a field, the weed can quickly overtake the field.
Palmer pigweed is not the most competitive weed on a single plant basis. However, it will overpower every other weed and the crop by sheer numbers.
I am not a “the sky is falling” guy. However, the best way to deal with a weed resistance problem is through prevention. The answers are not easy for prevention. But the answers for prevention are better than the answers for cure after the problem blows up.
I intend to hammer at this topic and bring in the perspectives of others. The weeds are talking, but are we listening?
e-mail: ford@weedconsultants.com
