The Clearfield rice system is great for controlling a lot of troublesome weeds besides red rice. I believe that is why it continues to take acres as fast as the seed supply will allow.
Besides red rice control, it is provides good control of most of the grasses and other troublesome weeds such as smartweed, nutsedge and most of the aquatics. I consistently hear growers say, “My Clearfield fields were my cleanest fields.”
Because Clearfield acreage will increase beyond that which red rice will justify, there is even more pressure on us to protect the system. Right now the Clearfield system is to rice as the Roundup Ready system has been in cotton, soybeans and corn. One only has to look at some of the resistance problems developing in those crops to know if we overuse the Clearfield technology, we can lose it.
In fact, many weeds have developed resistance to the ALS-inhibiting herbicides such as Newpath and Beyond much more quickly than resistance problems developed with glyphosate.
I continue to recommend a rotation between Clearfield rice, alternate crops and conventional rice.
On weeds other than red rice in the Clearfield system, however, we can do some things we didn’t do in the Roundup ready crops. Overuse of the technology will result in red rice resistance.
The worst thing that does is put you back to controlling or managing (or living with) red rice like you did before Clearfield. That is an individual grower’s decision on how far he wants to push the envelope toward that happening.
I believe the biggest long-term threat from overuse of the Clearfield system is barnyardgrass resistance. We can help prevent or delay barnyardgrass resistance by using alternative herbicides in the Clearfield system.
Last week I wrote that I recommend Command as a pre-emergence herbicide in the Clearfield system. It removes a lot of the barnyardgrass pressure, it improves sprangletop control, and it provides an alternative mode of action.
In addition, there is more quinclorac being used in Clearfield systems for both grass and broadleaf weed control.
Two of the primary weeds that escape Newpath and Beyond treatments are hemp sesbania (coffeebean) and jointvetches (indigo). When we grew these weeds for seed to use in our research plots, our weed control program to keep all other weeds out was a 2X rate of Newpath!
I get a lot of questions on what to add to Newpath to get these weeds without having to make a separate trip. A 0.5 pound rate of quinclorac (Facet or Quinstar) in the program early takes out a lot of the coffeebean and indigo pressure and provides residual.
A lot of growers are using Clearpath as one of the Newpath applications. That treatment provides 0.4 pound of Facet, which is close. If you use Clearpath for the first application you can get residual and then add something like Permit, Strada, Permit plus Grandstand, Aim plus Grandstand, Super Wham or Duet in the next application to control any escapes.
Getting the quinclorac out there not only takes out a lot of the broadleaf pressure, but it also provides another mode of action for the barnyardgrass.
A herbicide that seems to be getting more and more forgotten is propanil. Several newer herbicides have replaced propanil for a lot of the barnyardgrass applications. However, we often forget how good propanil is on a lot of the broadleaf and aquatic complex. I believe the reduced use pf propanil is responsible for a lot of the increase in the “non-traditional” rice weeds we are experiencing. Propanil is an outstanding tank-mix partner with Newpath.
Of course, you can not use every herbicide I have mentioned in the same field, but they present a lot of opportunities to alternate herbicide modes of action in the Clearfield system.