Arkansas clears rice herbicides

In the grower meeting I wrote about in the last article, Bob Scott expressed some frustration over the lack of new herbicides for rice. We are definitely stuck in a rut with most every rice herbicide being old enough to be off patent.

The Arkansas State Plant board recently granted three new registrations for “old herbicides.”

Broadhead is an FMC premix of quinclorac and carfentrazone — the actives in Facet and Aim respectively. It is a dry flowable formulation that I believe has the potential to be a good product for us.

The labeled rate of Broadhead will provide the equivalent of around a 0.5 pound product rate of Facet 75 DF and around 1.3 ounces of Aim equivalent. We currently tank mix quite a bit of Facet and Aim — often with other herbicides like Ricestar HT and Newpath, so this mixture would be a natural.

It will also be interesting to see if this dry formulation of carfentrazone has less potential for antagonism with the grass herbicides like Ricestar HT and Clincher than the Aim EC product has shown.

When we evaluated a lot of the Aim tank mixtures with the grass herbicides in research they were dry formulations of Aim and we saw little to no loss of grass herbicide activity. However, when Aim was switched over to the EC formulation, there have been antagonism issues.

The dry formulation may also have better spray droplet characteristics compared to the EC formulation. In general, EC formulations of about anything produce finer droplets than dry formulations.

Most weed control programs begin with Command applied pre-emeergence. More consultants are coming back with quinclorac before weed emergence. If broadleaf weeds have emerged, Broadhead can have a nice fit. Where grasses have emerged, Broadhead can be a good herbicide to mix with Ricestar HT in conventional rice and with Newpath in Clearfield rice. If they discount the carfentrazone in the Broadhead it will make it even more attractive.

The next herbicide that was approved by the Plant Board was Ryzon which is MANA’s 75 DF formulation of quinclorac. Albaugh’s Quinstar 4F and Quinstar 75 DF quincloracs were approved a couple of years ago. With Facet and Clearpath to go along with Ryzon, Quinstar and Broadhead formulations of quinclorac-containing herbicides, you have a lot of choices, and I think choices are good.

The third product approved was Alert, Cheminova’s new formulation of clomazone, which is the active in Command. This is the first new clomazone formulation introduced since Command 3 ME.

University and private testing conducted to date indicates Alert should perform equivalent to Command. Ronnie Helms, Dennis Gardisser and I did the spray deposition studies necessary for the registrations of Alert, as well as Ryzon and Broadhead, and the data indicate they have similar spray droplet characteristics as their standard counterparts.

The good news with all three of the herbicides is they offer farmers choices just as other generic products on the market do. Choices are good and they often result in favorable pricing opportunities for growers.

The news would be much better if we were seeing some promising new herbicide chemistry for rice coming along. Until we do or until we can somehow break the ice in the GMO area in rice to be able to go forward with something like LibertyLink rice, it is going to take a diligent resistance management program to hold things together.

I am writing this from an International Weed Resistance Management conference, so maybe I will hear some earthshaking news.

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TAGS: Rice
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