Last year I could not have been more pleased with the performance of Newpath herbicide on red rice and annual grass weeds. Most folks followed the recommendation for making a preplant incorporated application with the first 4-ounce-per-acre shot of Newpath followed with a timely second application of 4 ounces early-postemergence.
Several fields also received around 0.25 pound per acre of Facet with the second shot to help out on broadleaves and barnyardgrass. Everything went pretty well.
This year has not been so smooth due to problems with weather and missed timings. Most of the problems this year, in my opinion, have been with the sequential postemergence label. This method was very appealing to everyone from an ease of application standpoint; however, nothing about making postemergence applications to rice has been easy this year. High wind, rain, and wet spots in fields have made getting the two postemergence applications out difficult.
In addition, there has been some difficulty in following the label the way it is written. Many applications have gone out early postemergence on the Clearfield Rice, but pre-emergence or (even worse) delayed pre-emergence in terms of the red rice.
These timings have been the least effective for red rice control of all that have been looked at over the last three or four years. Also, to be effective, the pre-emergence and delayed pre-emergence treatments need to be flushed, even if the soil is moist and all is well at the time of application.
For the sequential postemergence to be most effective, it needs to be applied at or around two- to three-leaf red rice, followed by a second application around 14 to 21 days later. Then flood the field as soon as agronomically possible.
Only time will tell if these pre-emerge and delayed pre-emerge fields that were supposed to be sequential postemergence fields will result in good red rice control. It should be pointed out that I am not indicating that any of these fields went out “off-label,” they merely were not timed well for red rice control.
Also, I do not think that this takes anything away from the Clearfield system. I think it will be a learning year. I have heard of several fields of Clearfield this year continue that look fantastic.
Other issues that have come up with the sequential postemergence applications of Newpath include the need for a reduced rate (0.8 pint per acre on a silt loam) of Command applied pre-emergence to help out on sprangletop, whether or not smartweed will be controlled, and aquatic weed control. These are not big problems if the preplant-incorporated route is taken.
Command applied pre-emergence in the sequential postemergence Newpath system seems to be working well. I will say that in our trials at Lonoke, Ark., this year CL161 does seem to be a bit whiter than some of the other varieties in side-by-side tests. It appears to be growing out of it fine at this point. This increased bleaching may be due to the fact that the CL161 has a lot of seedling vigor and comes up faster and is exposed to the Command sooner.
As far as the smartweed problem goes, I am not sure that I have a good answer at this point. Many are choosing to tank-mix Newpath with 1 to 1.6 ounces per acre of Aim. This has been a smartweed year, and Aim is being put to the test.
There would seem to be some potential for antagonism with this combination; however, I do not have enough data at this point to say. There is enough going out across the state that time will tell.
I rate Newpath about a 7 on smartweed, when applied preplant incorporated followed by postemergence.
As far as aquatic weeds go, many are using Duet with the second shot applied preflood. With many of the first applications going out so early, aquatic suppression with Newpath alone may be good enough.
I have been told that there are between 175,000 and 225,000 acres of Clearfield rice this year. We should all know a lot more about these sequential postemergence timings after this year.
Bob Scott is the University of Arkansas Extension weed specialist. [email protected].