There seems to be a little more interest all the time, even at the grower level, about the potential for resistance or species shifts with Roundup Ready crops. From the beginning, it has been obvious that the weed control technology in the Roundup Ready crops is superior to conventional systems.
The ability to control some weeds in soybeans, such as Palmer pigweed and sicklepod, makes that system the only choice in some situations. The ability to control a broad spectrum of weeds, including red rice and johnsongrass, with a single herbicide is a big advantage.
Perhaps I get the most farmer testimonials on the fact that using Roundup Ready crops is just so simple. Some laugh, but my program of spraying Roundup, Touchdown or an equivalent generic every Monday morning until there is nothing but soybeans is simple and it works.
I have been a proponent of increasing our acreage of Roundup ready soybeans simply due to the number of "grown-up mess" calls I get each year. It seems now everyone is figuring that out and the acreage is increasing dramatically. Of course, it has not been weed control issues that has held it back to this point.
If one assumes the GMO issue isn't going to impede acceptance, the use of Roundup Ready crops will continue to increase. It is currently used on well over one-half of our soybean acreage and making a big surge forward. We need to think about how we make this technology last far into the future. Unless chemical companies have a sudden turn around in the development of new herbicides, what we have is what we are going to have for the foreseeable future.
So, now you have a technology that is broad spectrum and kills difficult weeds. It is simple. It is cheap and getting cheaper.
Will weed shifts or weed resistance occur with this technology? It isn't a matter of "if" but "when." The nice thing is that you can have the major input into when this occurs on your farm. When it occurs will be determined by how badly you overuse the technology.
Some will tell you not to worry about it. I can't guarantee you how quickly you will have problems if you overuse the technology.
Some will tell you to just "throw a little of this herbicide or that herbicide" somewhere into your program and you won't have to worry about it. Maybe that is true, but I would go further.
You can rotate Roundup Ready crops with non-Roundup Ready crops. Even where you are primarily into soybeans and wheat, there is no reason to plant Roundup Ready soybeans every time. Even in the worst of the grown-up messes, there is no reason that a couple of cycles of Roundup Ready soybeans should not clean them up tremendously. Then, you can go back to a conventional program for a cycle or two.
In the cleaner situations to start with, you can alternate systems even easier. This time of year is planning time. Set up a plan to rotate your weed control strategies.