There is good news now about Clearfield rice. The Canadian clearance has been granted, clearing the way for the technology to be used for both seed rice and commercial rice production.
The challenge now will be to choose the fields where Clearfield rice best fits and to do those things required to make it work.
Since we will be able to use the technology this year, I will make Newpath the next herbicide in my series. Listening to the University of Arkansas rice production folks present information in grower meetings this winter, I believe the performance of CL 121 and CL 141 varieties will dictate the technology be used primarily in the most heavily infested red rice fields.
As stated in previous articles, these are not bad varieties. However, the variety performance data shows they do not yield with the elite varieties like Wells and Cocodrie. The variety folks often use the term that they have yield potential more like Drew or Cypress, which are still considered good varieties.
The disease rating on the CL 121 and CL 141 varieties also would indicate they will need a full fungicide program. Therefore, as a grower, you will have to consider the performance of the varieties, projected production cost, and your weed problem when deciding whether or not to grow one of these varieties.
While weeds have to be controlled in every field, I still feel choice of variety is the most important decision you have to make growing the crop.
I feel one of the most important factors in determining the long-term future of the Clearfield (or any other herbicide-tolerant crop) technology, will be whether or not the breeding effort to produce elite varieties will be sustained.
The herbicide Newpath has been used for years in soybeans as Pursuit. It has provided nearly 100 percent control of red rice in four years of research at the University of Arkansas. This has been as a preplant incorporated treatment, followed by a postemergence treatment applied preflood.
However, the Newpath treatment is capable of much more than just a red rice treatment. The ppi, followed by postemergence treatment, is rated an 8 or above in the new MP-44 on all of the major grasses, nutsedge, rice flatsedge, purple ammania (red stem), and ducksalad. It will also give some suppression of smartweed and morningglories. Of the grasses, it tends to be weakest on sprangletop.
For weaknesses, it releases water hyssop, coffeebean, curly indigo and eclipta. These can be controlled, however, with a tank mix partner in the postemergence treatment.
If you get optimum performance out of the technology in your fields, our research indicates that 4 oz/A of Newpath applied preplant incorporated, followed by 4 oz/A of Newpath plus a propanil product postemergence, should be a pretty complete program.
If better varieties continue to come along, this technology has the capability to control red rice and compete very well with other herbicide programs for general weed control. One new variety, CL 161, which most experts feel is a step up from CL 121 and CL 141, will be grown for seed this year.
Ford Baldwin is a former University of Arkansas Extension weed scientist.