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Don’t let weeds get out front

Arkansas has had some rain but a lot of it has been scattered. More is in the forecast and I hope everyone gets one.

I am very concerned that the relative ease of weed control last year has too many folks lulled to sleep this year. I know there are a lot of residual herbicide applications in rice that did not get applied timely or if so did not get activated before a flush of grass came through. In those situations, you have to load up right now to get things under control.

If barnyardgrass gets past the four-leaf stage it can be a struggle the remainder of the year. Speaking of barnyardgrass, hopefully you read the front page article in April 23 issue of Delta Farm Press that ALS-resistant barnyardgrass has been confirmed in Arkansas. The ALS inhibitors for grass control include Newpath, Beyond, Regiment and Grasp. The weeds are talking, is anybody listening?

Thus far, the spring has been rather cool. When temperatures are cool, Ricestar HT has been a much better postemergence grass herbicide in conventional rice than propanil. In the fields with grass escapes, 24 ounces of Ricestar HT tank mixed with either a quinclorac product or Command has been an excellent treatment across the board on barnyardgrass, sprangletop, broadleaf signalgrass and crabgrass.

I receive more calls each year on crabgrass control. That is normally a grass that water controls. However in high populations it needs to be controlled and Ricestar HT is the best postemergence herbicide on it. Where the grass is only barnyardgrass and the rice gets three to four leaves, Regiment has been a very consistent herbicide the past few years when the correct surfactant is used with it. I also recommend tank-mixing it with a quinclorac or Command for resistance management.

In Clearfield rice, I do not recommend Newpath alone for barnyardgrass control. It has been too inconsistent the past several years and it also is not a good resistance management strategy. Consider Clearpath or tank-mixing Newpath with quinclorac, Command, Broadhead, Rice Beaux, Rice Pro, or a propanil product. There are a lot of choices depending on the situation.

I can only cover things in general terms in an article. The main point to leave you with is when rice gets to the four-leaf stage, there should be nothing between the drill rows but soil.

In soybeans, I am concerned Arkansas is about to become the “Palmer pigweed” state. I am just not seeing the sense of urgency it will take to control resistant pigweed. There continues to be a reluctance to change technologies in the name of “cheap glyphosate.” At the rate we are going, it isn’t going to matter in a few short years if they give it away.

I have also talked to several growers who felt they could not stop planting long enough to spray their pre-emergence herbicides. That is not a criticism, but one or two precious rains for activation have slipped away in the meantime. I hear some saying you have 10 days to get a pre-emergence herbicide activated in soybeans. You need it activated in three to five days because you can have a solid ground cover of pigweeds in 10 days after planting.

If you have glyphosate-resistant pigweeds, you have 10 to 14 days after emergence to kill them with Flexstar or Ultra Blazer. In many cases, it will take two (at least) very timely postemergence applications. Keep in mind that controlling resistant pigweeds in Roundup Ready soybeans is just like controlling them in conventional soybeans. The focus must be on the conventional herbicides — not the glyphosate.

My objective is to encourage rather than discourage. However, failure to use residual herbicides, failure to get them activated timely, and missing the timing of the first postemergence herbicides were the downfall of the conventional programs when we had to depend on them. My concern is not enough folks realize how difficult pigweed control with conventional herbicides can be — especially if there are any slip-ups.

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TAGS: Rice
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