Rice Weed Management for Unpredictable Weather | Corteva Agriscience™

Start Clean to Stay Clean

Written By Richard Costello 

Designing a weed control plan that adapts to Mother Nature’s whims is tough. Former Rice Consultant of the Year, Richard Costello, shares his tips.

It has been said that failing to plan is planning to fail. That is never truer than in rice weed control.

With that said, the year usually dictates those plans be adjusted or completely thrown out the window. Because it is difficult to predict what kind of year Mother Nature will give us, we must go into each growing season with an open mind about weed control programs.

It is an absolute necessity to start with a good burndown. I start with glyphosate plus 2,4-D, adding a residual product containing flumioxazin if the ground is ready to plant. If weather pushes burndown closer to planting, I pull the 2,4-D and add a tank-mix partner with a shorter plant-back restriction.

My go-to preemergence herbicide tank mix at planting is glyphosate plus clomazone plus Sharpen. Rates can be adjusted based on soil type and weed spectrum, and this tank mix provides residual activity for many of the hard-to-control weeds prevalent in Mid-South rice fields. 

For an early postemergence timing (one- to two-leaf rice), I add more residual and select herbicides based on which weed spectrum you need to control.  

Products like quinclorac, clomazone and pendimethalin, and tank-mixed combinations of these active ingredients, provide good residual grass control and some residual suppression of broadleaf weeds. Grasp® SC herbicide or RebelEX® herbicide can provide added control, depending on weed spectrum, and can be combined with one of the above to increase residual control. 

I still use some propanil products occasionally if weeds are really small because it controls a broad spectrum of weeds. Propanil also seems to enhance Newpath herbicide in the CLEARFIELD® Production System.

Regardless of application timing, what herbicide product you use depends largely on weed spectrum and weed size. If you have weeds that have escaped preemergence treatments and are large, especially grasses, quinclorac plus Clincher® SF herbicide or Ricestar herbicide may be needed.

In conclusion, scouting your rice fields to determine weed spectrum and size to select proper herbicides is paramount. The products are my go-to herbicides for my game plan, but they are not a complete list of what I may recommend depending on the scenario.  

I hope everyone has a great year. Good luck.