Weather difficulties set up weeds in some late rice fields

Most of the calls I am getting now are about typical big grass or grown-up weed messes. There are, however, a lot of clean fields.

Fields that were planted early this year had excellent moisture to make residual herbicides work well. A lot of the fields have required nothing but some broadleaf and sedge attention.

A lot of the later planted rice, however, has gone through typical dry weather woes of trying to make herbicides work. And high winds kept a lot of treatments on the applicators' books for a week to two weeks before being applied.

There has been the understandable reluctance to flush due to high fuel prices. A lot of fields were caught in “no man's land” — between the rice being too small to flood but far enough along that there wasn't time to flush for a herbicide application and then dry to fertilize for the permanent flood.

This has not been an easy year, to say the least. Any of the situations I've described can lead to weed control difficulties, and a lot of fields have been through combinations of problems. Calls about situations that involve any number of large grasses, broadleaves and sedges are typical.

Sometimes it is possible to clean up things with one application. Grass size, possibilities of tank mix antagonism with some treatments, and proximity of adjacent crops with others often make it difficult to come up with one treatment that does everything.

My first rule is to get the grass out. You can lose a rice crop to grass — especially barnyardgrass — but you will not lose one to broadleaf and sedge weeds. That does not mean controlling them is not important, but I always think “grass first.”

If there is a choice, I seldom recommend flooding up on big grass. The exception is when it is simply so dry there is no realistic possibility of a pre-flood treatment working. Post-flood treatments can work well, but I like saving them because they are the last line of defense.

Sometimes the grass is thick enough and big enough that I do not have confidence that one application of anything will get it all. In those cases I try a pre-flood herbicide followed by a post-flood herbicide for a “one-two punch.”

In other cases, apply a pre-flood treatment and hope it works. If it does not, then you still have the post-flood option. If you flood up and the post-flood herbicide fails, things go south in a hurry.

Making two post-flood treatments is sometimes possible, but if the first one fails, the possibility of a second treatment working is slim.

I recommend Ricestar HT plus Facet or Quinstar, Regiment, Regiment plus Facet or Quinstar, Regiment plus Ricestar HT, or sometimes just Facet or Quinstar alone, depending on the situation.

If it is too dry for any of these to work, you have to think post-flood. With a post-flood treatment the grass cannot be covered. Sometimes if it is small enough that the water will cover it, you can use a flush/flood program — wet the field, get the herbicide out, then raise the flood. Otherwise, you have to let the grass come through the water.

Post-flood, I recommend Regiment, Facet or Quinstar alone, Clincher or Clincher plus Facet or Quinstar and sometimes Ricestar HT plus Facet or Quinstar, depending on the situation.

Whatever you use, hit it hard. Everyone is looking to save a dollar, but I get far too many calls from growers who would not spend the money up front to make sure they did not miss but then are willing to spend a ton on something that likely will not work after the fields grow up.

I wrote weeks ago that this would be a throw-the-book-out year and it is — especially on late-planted rice. Call if I can help.

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