Sold on cut-rate herbicides

For the past 15 years, sugarbeet growers have been applying herbicides in narrow bands over their emerging crops. That practice saved money over broadcast spraying, but it allowed weeds to sprout and spread between bands.

Beginning this year, Idaho sugarbeet growers can have it both ways: they can blanket their fields with herbicides, but do it so thinly that they wonÕt need additional herbicide. Why? Because an uptake-enhancing substance called methylated seed oil makes applications at one-third the standard rate as effective as the full rate.

A study by weed scientist Don Morishita showed the value of reducing herbicide application rates in sugarbeets. Photo by Andy Arenz.

By offering growers broader coverage, less need for backup cultivation to control weeds, and the flexibility to apply weedkillers aerially, "micro-rate" applications can save growers money. Amalgamated Sugar Co. representative Del Traveller says he would "be surprised if we didnÕt have nearly 50 percent of growers try it."

Last year, extension weed scientist Don Morishita organized a pilot study involving up to 500 sugarbeet growers. Ninety percent of growers who reported back said they were "very satisfied with the level of weed control and would use it again."

Two years of research studies by Morishita at Kimberly and by Oregon State University counterpart Corey Ransom at Ontario confirmed that combinations of micro-rate herbicides can provide excellent control of most weeds except kochia.

In part through their efforts, herbicide manufacturer Aventis will allow growers to legally apply combinations of seven different herbicides, augmented with methylated seed oil, at below-label ratesÑalthough Aventis wonÕt guarantee success.

-Marlene Fritz