Clincher herbicide has performed well this year in its first full season of use. The wet conditions earlier this year were perfect for Clincher. Before the season, representatives from both Dow and the university were promoting Clincher at primarily a post-flood timing. That is, flood the rice, let it settle a couple of days, and then spray for big grass control.

The number one question I got on Clincher this year was: “I know I am supposed to wait until after flood, but the ground is soupy wet. What do you think it will do?” My answer was, “If it is going to work, it should work now.”

The question I have been getting lately is: “Do you know where I can get some Clincher?” I do not think anybody could have guessed that so much would be used this year.

Last year we recommended only the 15 ounces per acre rate of Clincher with crop oil concentrate. Prior to flood in this earlier timing, 13.5 ounces per acre has seemed to work well. I conditions were excellent for it to work.

One thing about spraying under “soupy” conditions was that coverage was excellent. Most of the grass was exposed above the flood or mud, and the spray solution made it to all grass tillers.

Last year there were lots of reports of only the main tiller dying or re-growth occurring in Clincher-treated fields. I believe that may have been due in part to the lack of spray coverage on smaller tillers down in the rice canopy. Most Clincher went out late last year, in a post-flood salvage timing.

Also obvious in my plots this year is that Clincher works better on smaller grass if the conditions are right and coverage is good. One recommendation I won't change is to make post-flood applications of Clincher no later than one week after flooding if possible.

As barnyardgrass heads out and goes reproductive, it has gotten harder to kill. I am seeing as much as a 40 percent reduction in control from spraying three days after flood versus 12 days.

The importance of good coverage was very evident on a field that turned out to be resistant to two grass herbicides this summer. The county agent said that two other herbicides (Facet and Super Wham) had failed. A shallow flood was on the field already. There were at least two different populations of barnyardgrass. One was over a foot tall, the other maybe 8 inches.

We were talking either Ordram or Clincher. I told the county agent that Clincher would probably be the way to go if we could get good coverage. We thought about using 20 gallons of water per acre as a carrier. However, I was concerned about getting coverage on the smaller grass, and we were not sure that the plane could do that.

We shot from the hip and sprayed 7.5 ounces of Clincher at 10 gallons per acre with crop oil concentrate flying north and south and then repeated that flying east and west, for a total of 15 ounces per acre of Clincher. The results were excellent.

There was the additional cost of two applications, but in the farmer's words, “It would have been worse if this third attempt at controlling the grass had failed.”

My project has a new MudMaster spray rig from Bowman Manufacturing in Newport, Ark., that we use to apply post-flood treatments. The number one benefit of this rig is that I stopped wearing out technicians by having them stomp through flooded rice at 3 miles per hour while trying to spray accurately.

The rig will make it possible for us to do more post-flood work with herbicides like Clincher and several other projects, including late applications of Newpath and Roundup drift to rice. The rig was purchased with support from the Arkansas Rice Promotion Board. My rice weed control program is made possible through their support and it is greatly appreciated.


Bob Scott is the University of Arkansas Extension weed specialist. bscott@uaex.edu.