Effective Weed Control Crucial For Good Crop

Hans Herkert
Growers Ag Service
Yuba City, Calif.RiceAdvice1

  • B.S., Ag Business, Chico State University
  • Licensed Pest Control Adviser
  • Certified Crop Adviser
  • Member of California Association of Pest Control Advisers
  • Vice president of CAPCA Sutter Buttes Chapter
  • Board of directors, Yuba-Sutter Farm Bureau
  • Has consulted for five years on rice, walnuts, tomatoes, prunes, wheat, beans, alfalfa and sunflowers
  • Enjoys working, duck hunting and golfing with wife Jillian

I grew up in the heart of California rice country in Colusa and, at an early age, attended many industry meetings with my father, who worked for the California Rice Commission at that time. I also had many summertime jobs working for farmers in my hometown. Upon graduating from Chico State University, I embarked on my advising career with Growers Ag Service in Yuba City.

GRANITE Herbicide from Dow AgroSciencesAlthough many farms enjoyed record yields in 2015, the California rice industry as a whole suffered due to reduced acres from drought. Weed control was very tough in areas that had too little water to maintain a constant flood. Today’s rice varieties tolerate stress well, but producing a good crop is dependent on effective weed control programs and rotation of these programs.

Each year we battle a number of troublesome weeds, and herbicide resistance is the largest problem we face with grasses and sedges. Herbicides that have proven effective for many years are starting to show some weakness as weeds develop resistance. Pest control advisers and growers recognize this problem and are rotating herbicides with differing modes of action.

Managing weeds early in the season will make cleanup applications more effective and less costly. A program that has worked well for me is a tankmix of Granite SC and Clincher CA around the 4-leaf stage of rice. However, this program requires that the field be drained prior to application and reflooded shortly after. With reduced water allocations, I focus on more water-efficient programs, such as applying granular herbicides into a constant flood irrigation. Cerano followed by Granite GR has yielded good results. A pre-flood, pre-plant application of Abolish, or an application of Bolero into the flood at the 2.5- to 3-leaf stage, is also a good water-efficiency program. In most cases, a follow-up application of propanil and Grandstand CA is required to manage weeds that escaped the early herbicide application.Screen Shot 2016-01-14 at 9.25.57 PM

Maintaining a constant flood by not allowing allotted water to flow out of the drain is important to water efficiency, but it can cause a problem with algae growth. Although some algae infestations can be severe, most problems are mitigated effectively with an application of copper sulfate, zinc sulfate or Green Clean. Algaecide timing is important and requires daily attention when the crop is in the seedling stage. Applications seem to be most effective when applied before the scum layer begins to lift from the soil surface.
In today’s climate, it is important that we maintain use of current crop protection tools, and that manufacturers continue to innovate and provide new cost-effective tools. Our industry has a lot going for it, and public perception of rice farming is in great shape as ricelands have been recognized for providing valuable migratory bird habitat. Rice will continue to be a staple throughout the world, and California is a great place to grow it.