Last week I ended the article with a comment that I felt clomazone (Command and now Alert) was the key to helping hold the Clearfield technology together. I feel ALS-resistant barnyardgrass is a bigger threat to the Clearfield system than resistant red rice.
The grower who depends primarily upon Newpath and Beyond for grass control could see this resistance develop quickly. I have always liked Command in Clearfield rice for both resistance management and also to simply take much of the grass pressure out so you could concentrate on red rice control with the Newpath and Beyond.
While barnyardgrass is the primary concern, we have seen an increase in sprangletop — especially tighthead sprangletop in Clearfield rice. Once sprangletop breaks in the Clearfield system, Ricestar HT and Clincher are the only two options for control.
Tighthead sprangletop resistance to both herbicides has been documented. While Ricestar HT and Clincher have a place in Clearfield rice, we do not need to get in a situation where they are being used for sprangletop control in the same field each year or each crop cycle.
Command provides a solid foundation for barnyardgrass and sprangletop control in Clearfield rice just as it does in conventional rice. You can apply Command pre-emergence, tank-mixed with the first postemergence Newpath application or as a split application.
The split applications are being used by more farmers and consultants each year. With the split, some of the Command is applied pre-emergence and the remainder is applied in the next trip across the field. The split allows you to reduce the pre-emergence rate enough to avoid most of the white rice. The second application will then extend the residual period.
The other advantage of the split is you are not depending upon the same rainfall event to activate all of your Command. Activating it all with one rainfall event can be good when it happens, but bad when it does not.
Another thing you can do for resistance management in Clearfield rice is use more quinclorac (Facet, Quinstar, and now Ryzon and Broadhead) before barnyardgrass emergence. You can do this as Clearpath or with Newpath tank-mixed with one of the above quinclorac products. Thus far, there has been much less barnyardgrass resistance to quinclorac applied pre-emergence than postemergence. Keep in mind, however, the quinclorac treatment will not help on the sprangletop problem.
Two other herbicides that you can rotate in and out of the program are Prowl and Bolero. Some Bolero may be sold alone but most of it will be in the propanil premix RiceBeaux.
I get quite a few questions about switching from Command to Prowl as a base program. I do not feel you can build a program around Prowl (or Bolero either) but it can make a nice tank mix, either delayed pre-emergence or early postemergence, in the right situations.
The Bolero treatments are likely to increase as an alternative treatment for sprangletop control. RiceBeaux makes a nice tank mix partner with a very early application of Newpath. That gives you three modes of action. You can mix it with Clearpath and get four modes of action. Heck, you can mix RiceBeaux, Broadhead (quinclorac plus Aim) and Newpath and get five modes of action if your banker will stay hitched!
My point here is not to suggest throwing every herbicide or mode of action at every field. That is the wrong thing to do. However, the Clearfield system needs a good rotated mix of herbicide modes of action used with it to remain viable.
Several farmers and consultants have commented that they are spending as much on conventional herbicides in Clearfield rice as they do their conventional rice and still having to use Newpath and Beyond. Some of that is simply going to be reality. Find a way to rotate Command, quinclorac, Prowl and the Bolero products in the Clearfield program. With that said, I still believe the use of Command will be the glue that holds it all together.
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