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Clearfield: too good for its own good?

I finished last week’s article with a statement about the increased number of barnyardgrass samples sent in to the University of Arkansas for resistance testing this year. I do not know what the numbers are yet, but the number of samples is up dramatically over previous years.

Several top notch consultants called me last year asking, “Doc, am I the only one who cannot kill barnyardgrass this year?”

Herbicides can fail for a lot of reasons. Last year started off bad from an environmental standpoint and went down hill from there. Usually when that happens, one can predict more trouble killing weeds and a weedier crop in general.

I am hopeful that a lot of our problems last year were due simply to the type of year we had. However, in a lot of the failure calls I received last year, after all of the discussion it seemed as if the herbicide should have worked.

It will be interesting to get the testing results from the samples sent in this fall.

Last week I also mentioned that the Clearfield acreage is predicted to increase significantly again next year. It would sure seem now that the acreage is well above the number that red rice would dictate.

It is certainly above our “ideals” from the introduction of a rotation of soybeans, Clearfield rice and conventional rice. In this scenario, the ideal Clearfield acreage would be around a third of the total. However, the acreage has increased well beyond this simply because weed control in general has been easier in Clearfield rice than in conventional rice.

I am in no way being critical of anyone who is increasing Clearfield acres — it is excellent technology. However, I believe if this trend continues, the technology will crash in a few short years.

In general, weed control has been easier in Clearfield rice. The obvious reason is you have all of the tools available for conventional rice plus Newpath and Beyond, which are excellent herbicides.

However, last year a surprising number of the barnyardgrass failure calls I received were in Clearfield rice. I had several calls where small barnyardgrass came right through two 4-ounce applications of Newpath and some where it came through two 6-ounce applications. Again, this does not mean it is resistant, but it sure raises a flag.

Also, it is a moot point whether it is resistant or not if you can not kill it.

Another concern that I have with the increased Clearfield acreage is much of this increase has been from the hybrids. Again, my intent is not say do not plant the hybrids — I am on record as being a fan of hybrid technology. However, I am also on record stating the current hybrids need more herbicide tolerance. The current limitation on Newpath rates and Beyond timing on the hybrids compared to the Clearfield varieties speaks for itself.

There is also the perception in the field among consultants that the Clearfield hybrids will not tolerate the same rates of some herbicides such as Command as the varieties will. What I typically see each year is when the Command turns it white, the consultant is reluctant to pull the trigger on the first Newpath application as quickly as he normally would.

In other cases, if the first Newpath application injures the rice, the consultant or farmer is reluctant to make the second application. In some fields this has made weed control in the hybrids more difficult. This results in more escapes and potentially more trouble down the road.

Before I get the cards, letters and e-mails, I am glad we have both Clearfield rice and the Clearfield hybrids. To date, the hybrids have allowed growers to make a typical conventional rice yield in a Clearfield system.

However, I am concerned that the continuing increase in Clearfield acreage as well as the reluctance by some to really go after the barnyardgrass and red rice in the hybrids is going to result in a train wreck. We are either going to have to carefully manage the current technology or find a way to get new technology. At present it seems as if both will be difficult.

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