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Zero tolerance for barnyardgrass

A lot of Arkansas rice fields are ready for the flood. I hope when the water goes on there is nothing out there but rice and soil.

There are a lot of different situations. Some areas have levees washed out due to torrential rains and in other areas farmers are flushing because it is so dry. This means in a lot of situations, weed control may be more challenging than it was last year.

I hope your goal is zero tolerance for barnyardgrass. That can be difficult, but with the resistance issues we are facing and the lack of any new chemistry on the horizon, you must preserve current technology if you are into farming for the long haul.

This may mean using an extra herbicide or making an additional application in some cases to control a scattered infestation that will not impact yield or grade.

I have had a lot of questions lately about using EC propanil in place of crop oil concentrate in several rice herbicide mixtures. I have actually recommended this quite frequently for the past several years. If the herbicide being used is one that could be recommended with propanil, the use of EC propanil for the adjuvant makes a lot of sense.

Herbicides I have commonly recommended this with have included quinclorac (Facet, Broadhead, and generics), halosulfuron (Permit and Halomax), Newpath, Aim, Londax, Storm and Blazer. Obviously this is not an “across the board” recommendation because there are some situations where the propanil may not fit because of drift issues or you do not want the extra heat.

However, in situations where you want to enhance the activity, it can be a good treatment. I usually recommend 1 quart of EC propanil where it fits. If you want more heat, some are running 2 quarts.

There are not many EC formulations available any more. One I know for sure is Rice Shot. Perhaps there are others.

Do not use the propanil as the adjuvant with herbicides it will antagonize such as Regiment, Ricestar HT and Clincher. Also, if you are trying it for the first time, do it on a small scale to see how it works for you.

I have had more calls lately on larger barnyardgrass. As barnyardgrass gets to the four-leaf stage, my favorite treatments in conventional rice are Ricestar HT plus quinclorac and Regiment.

If there grasses other than barnyardgrass are present, Ricestar HT plus quinclorac is the preferred treatment. I usually recommend 24 ounces and 0.5 pound of Facet, or the equivalent in a generic, or Broadhead.

If the problem is only barnyardgrass, I often recommend Regiment. Be sure to use one of the approved surfactants with the Regiment. In Clearfield rice, I usually recommend the highest recommended rate of Clearpath when the grass gets to the four-leaf stage.

If quinclorac-resistant barnyardgrass is present, you may need to use a conventional treatment to control it.

Tighthead sprangletop continues to increase in Arkansas and the only two postemergence options are Ricestar HT and Clincher. It is more difficult to control with either herbicide than loosehead sprangletop. Preflood, I usually recommend 24 ounces of Ricestar HT and do not recommend tank mixing it with any other herbicide. Post-flood I recommend either product interchangeably.

I also get an increasing number of calls on crabgrass in rice each year. Normally this is a weed you control with water. However, in some fields this is not working. Ricestar HT at 24 ounces is the best treatment, but it is not always perfect. It will usually rot the terminals and suppress it enough to finish with the flood if you spray it early.

I also have received several calls on fall panicum. On this grass, Clincher is the best herbicide. Ricestar HT can be effective if it is two- to three-leaf. However, if it is a major problem or if what is there has any size to it, Clincher is easily the best choice.

Do whatever it takes to clean up the crop prior to flooding. Now is not the time to cut costs if you have a preflood grass problem. It will cost you dearly later if you miss.

TAGS: Soybean
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