At winter and spring meetings this past year, I warned Clearfield rice growers that Newpath herbicide would not perform as well in a dry year as it had in the past two relatively rainy years. I was afraid that growers might get overconfident in the ability of Newpath to control red rice and fail to flush in preplant incorporated or pre-emergence applications or make sequential postemergence applications to dry ground or drought-stressed weeds.
Our research at the University of Arkansas has shown that good Newpath performance on red rice, barnyardgrass, broadleaf signalgrass and sprangletop is directly tied to having good moisture.
This was a dry year for most in Arkansas. We have struggled with moisture since day one across the state. In addition, Clearfield acres were up this year, giving us more opportunities to fail.
However, due to some hard work on the part of many growers, most Clearfield fields were flushed this year. For the most part, red rice control has been good. Before the calls start coming in, I have not forgotten about those of you that I visited this year that were less than happy, but the majority of Clearfield fields are the cleanest ones we have this year. I think this is due in part to the extra effort to manage the water on these fields, maybe at the expense of some other fields.
I was a bit concerned earlier this year when the calls started coming in on the use of Beyond under our 24C label for red rice suppression where Newpath has failed. But after speaking with BASF and looking at the volume of calls that we have gotten at the Extension service, the increase in the amount of Beyond used seems to be proportional to the increase in Clearfield acres. To me this means that the performance of Newpath and the Clearfield system was about as good this year as last.
Beyond has performed well this year under the 24C. I got the opportunity to see some fields that had big barnyardgrass and some broadleaf signalgrass in addition to red rice. Beyond performed pretty well on these other grasses as long as the seedheads had not yet emerged.
The use of Beyond herbicide has undoubtedly prevented the out-crossing of the Clearfield trait to red rice on numerous fields this season.
As Clearfield acres increase, I am concerned about stewardship and the rotational intervals on all these Clearfield fields. For the best prevention of out-crossing, Clearfield rice should be rotated with Roundup Ready soybeans.
However, many fields are not being rotated. The risk of the Clearfield trait out-crossing to wild red rice is much higher in a continuous Clearfield rice system than it is in a system where Clearfield is rotated with soybeans and maybe even a year of conventional rice after that.
It is my understanding that BASF has produced almost enough seed to plant 50 percent of all U.S. rice in Clearfield rice next year. I do not understand how this large acreage can be maintained while following BASF's own stewardship program.
Bob Scott is the University of Arkansas Extension weed specialist. e-mail: firstname.lastname@example.org