PREFLOOD CONTROL OF LARGE BARNYARDGRASS

Many calls are coming in right now on preflood grass control. This is a time when many turn to RiceStar HT to take out larger grass or grass that is resistant to propanil, Facet or both. The federal label for RiceStar HT goes up to 17 oz/A, however, in Arkansas we have a State 24C label for rates as high as 24 oz per acre. When do you need the higher rate? Pretty simple, the larger the grass the higher the rate. On small grass, 2-3 lf, 17-18 oz of RiceStar will do the trick. As barnyardgrass and other grass gets bigger, I up the rate. At 2-3 tiller grass I pull the trigger on the 24 oz rate. I may also suggest some Facet to help out.

What about Clincher. I think that Clincher can perform about as good as RiceStar HT on most grass weeds if they are small. I like Clincher early in the season tank-mixed with a residual product on 1-3 lf grass. I like the higher rates of RiceStar HT on larger grass preflood, especially if conditions get dryer. Once we get to post-flood, I think Clincher has performed a little better than RiceStar HT. One exception to this is fall Panicum, I usually recommend 15 oz/A of Clincher, regardless of timing.

If it is a true pre-flood timing, that is your going to flood now, I say apply the RiceStar HT and flood. However, often we may be another week to 10 days from flood. If this is case, add a residual grass material to extend the weed control until you get a flood on. Command (8oz), Prowl H2O (2 pints), or Facet (0.33 to 0.5 lb/A) will usually do the trick.

On Clearfield rice preflood applications, it often takes a leap of faith to apply Newpath and flood. Often there is grass present that is sick, but not dead. Also, for whatever reason, the grass may not be sick at all. If it is below the 3 leaf stage Newpath should do the trick. If it has reached the 4 leaf to 1 tiller stage I add Facet or RiceStar HT to help clean it up. Usually barnyardgrass that is sick will not survive a second shot of Newpath and the flood. Newpath is weak postemergence on sprangletop and fall panicum. I have not seen an advantage from increasing the Newpath rate from 4 to 6 oz/A.

It is often necessary to add some Permit or another broadleaf product to RiceStar HT when applied pre-flood. I am OK with most tank-mixtures, however, the liquid Aim formulation has caused some problems it terms of antagonizing grass control with RiceStar HT. The new product Broadhead (quinclorc + Aim premix) contains a DG formulation of Aim. We are looking at this one this year to test for antagonism. We have reason to believe it will not be as antagonistic as the liquid form.

Another preflood option that I turn to a lot on bigger grass is Regiment. Since we discovered what a little UAN can do in an adjuvant like Dyne-A-PAK, Regiment has become a much more consistent option for Barnyardgrass. It also controls a host of broadleaves. It weakness at this timing is a lack of control of all other grass weeds.

I left out a bunch of stuff, for many propanil or propanil combinations with other products work great. I usually don’t get calls about these fields. There are many other options for broadleaves and stradegies for grass, can’t cover them all here.