It occurred to me the other day that a lot has been written this year about Newpath drift and some injury that has occurred on Clearfield rice from Newpath applications. These are important problems that will occupy much of our time this year, but Newpath performance on red rice and other weeds should not be overlooked.
I am seeing and getting calls from field men and growers about clean Newpath-treated fields, even though applications were delayed, the sequential-post applications were made only days apart, a wide assortment of tank mixes were used and other assorted application problems were encountered. For most, Newpath has performed well.
I hope that in some cases this performance has not been too good! I have seen and been made aware of several fields where only one 4-ounce-per-acre application was made. For complete control of red rice, company and university data agree, a two-shot program is required.
The big fear, of course, is of outcrossing of red rice and Clearfield rice if the two flower at the same time. In some cases where only one application was made, the grower may get by with it this year. If on the basis of this experience, however, people decide this will be the case everytime, I fear they are headed for failure.
In our research, single 4-ounce applications of Newpath usually result in less than 80 percent control of red rice.
With all the drift problems associated with post applications of Newpath this year, I and others will probably talk more about the older soil (preferably preplant incorporated) application followed by one post-shot program. I believe this program offers the broadest spectrum of weed control and looks good on red rice as well.
The program will require a flush for optimum activity, but I have heard few complaints from those who have done it.
Tank-mix partners this year have included Aim, Grandstand plus propanil, propanil, Duet and a wide range of others. I have received no complaints to speak of about weed control with any of them.
The key weeds that a tank-mix partner must control in a Newpath-only program are Northern jointvetch (indigo) and hemp sesbania (coffeebean). Newpath is also weak on eclipta and some other aquatics (especially in the sequential post programs).
In my research, as long as applications are made early, most tank-mix partners have looked good. I prefer to use 1 quart per acre of propanil with Grandstand rather than Grandstand alone.
Aim looks much better if it is applied very early to smaller weeds.
We had some extensive research with Duet this year. So far, it looks great with the first or second shot of Newpath. I like the 3-quart rate of Duet and will look at 2 and 2.5 quarts next year.
Based on this second year's performance, I would say that Clearfield rice and Newpath have found a place in rice production. How long it will be around depends on variety development, weed resistance and our ability to prevent outcrossing.
Newpath appears to be providing commercially acceptable control of barnyardgrass, signalgrass, sprangletop, nutsedge, morningglory and others. If high-yielding varieties come along, I think you will see Newpath find a fit on non-red rice acres, based on the performance of Newpath on weeds other than red rice.
Bob Scott is the University of Arkansas Extension weed specialist. e-mail: [email protected]