One of the more fun things we are still working with in our rice weed control program is the Clearfield rice technology for red rice control. There are a lot of interesting aspects of this technology.
It continues to look very promising for control of red rice and other difficult to control weeds. However, it may well be a challenge to get the system to perform near 100 percent in the field and to preserve the technology over an extended period of time.
Tomilea Dillon, a Ph.D. student working with me and Ron Talbert, our senior weed scientist at Fayetteville, Ark., is in the fourth year of a very large research program with Clearfield rice. In her work, the Newpath treatments continue to provide outstanding control of grasses, yellow nutsedge and red rice at our Lonoke, Stuttgart and Lodge Corner locations.
It also continues to look good on work on clay soil by Ken Smith, our weed scientist at the Southeast Research and Extension Center at Rohwer.
The best program has been a preplant incorporated treatment, followed by a postemergence treatment, and the most constant rate has been 4 ounces per acre followed by 4 ounces per acre.
When I look at our work over the past years, I wonder “how can this program possibly fail?” It has been that good.
However, Andy Kendig, my counterpart in the Missouri Bootheel, has had complete failure with the soil application of Newpath for the past three years. He has both silt loam and clay soil locations. Look at his plots and you can't tell they have been sprayed.
The past two years, I have both looked at and had telephone calls about seed fields where the soil application of Newpath has failed. Sometimes there have been obvious reasons, such as the treatment being applied pre-emergence and receiving no rainfall or flushing. In other cases, like in Andy's plots, about all you could say is “it should have worked.”
We do know that if the soil application part of the program completely fails, the postemergence treatment won't clean things up. The success of the system depends upon getting excellent activity from the soil-applied treatment, then finishing things off with the postemergence treatments.
In Andy Kendig's work, two postemergence applications of Newpath have provided much better red rice and barnyardgrass control than the preplant incorporated followed by postemergence treatments.
That has also been an excellent treatment in Tomilea's work.
In our case, we have had too much crop injury from the two postemergence treatments. However the work we have with the “second generation” varieties, indicates the injury problem is solved.
There is no comparison in the tolerance between the current Clearfield varieties and the new varieties coming. This is primary technology and our first real solution to controlling red rice in dry-seeded rice. However, the inconsistency across other people's work bothers me. It means we have work to do. As the technology becomes available, hopefully next year, everyone must be “on the same page” to get it to perform consistently.
It will not be a system where you can just use it any way you would like or that someone tells you to and get it to perform at a 100 percent level. We must strive to get 100 percent red rice control with the system. If you do not, the technology could be short lived. I'll tell you more about that in the future.
Ford Baldwin is an Arkansas Extension weed scientist. e-mail: [email protected]