While we are harvesting rice plots we have the opportunity for the last look at how various weed control treatments performed this year. It is also a time when I get a lot of ideas on what we need to work more on next year.

Fall panicum is one grass I had an increased number of calls on this year. Some of the calls made it sound as if they had “thrown the book” at it and nothing would control it.

I have always had some fall panicum in my research area near Lonoke, Ark. This year, however, I had a lot more.

This is a good time of the year to evaluate fall panicum in plots. It heads later than most grasses, which, I assume, has something to do with the name fall panicum.

Through the years, I have achieved good fall panicum control with most treatments that provided good control of barnyardgrass and broadleaf signalgrass. This is pretty much true this year with a few exceptions. Command, Facet, propanil and any programs containing these generally do an excellent job on fall panicum.

Earlier this year, I thought I was noticing that Ricestar was weaker on fall panicum than the other new grass herbicide, Clincher. Later in the season some of the Ricestar treatments provided good fall panicum control.

Looking at the plots now, however, it is easy to see some of the differences. Some of the high-rate treatments of Ricestar, properly timed, provided adequate control. However, at lower rates, later timings, or when tank mixed with some herbicides that can cause antagonism, fall panicum escaped.

Looking at the plots now, it is obvious that Ricestar is weaker than Clincher on fall panicum. On the other hand, Clincher can be a little weaker than Ricestar on sprangletop.

I do not know what the registration status of Clincher is at this point. The federal registration for Ricestar was recently approved.

Regiment is another experimental herbicide that totally released fall panicum in our plots this year. I do not know the registration status of this herbicide either.

Regiment has provided good barnyardgrass control on occasion and has been one of the better treatments on larger barnyardgrass. It also has provided good control of coffeebean in some of the plots.

Most of the other treatments that have always looked good on fall panicum looked good again this year. This is especially true for any programs that included Command or Facet.

With Ricestar and Clincher for next year, we will continue to look at the tank-mix antagonism issue. As I have stated in previous articles, Permit has caused the greatest loss in grass control when mixed with Clincher or Ricestar. This is very evident with fall panicum in the plots ahead of the combine.

A tank mix of Storm and Ricestar was one of the best treatments using these herbicides. We will also continue to evaluate the mixture of Ricestar and Whip. Whip can add some activity to Ricestar, but it will have to be at rates higher than the 2 to 4 ounces everyone was messing around with this year.

Because Whip injury so rarely occurs in research plots, it makes this treatment hard to study. We will keep working on it.


Ford Baldwin is an Arkansas Extension weed scientist.
e-mail:
fbaldwin@uaex.edu