New Process Keeps Biocontrols Alive Longer

Dozens of fungi and bacteria have been tested and found effective for controlling weeds that infest crops and rangeland. Unfortunately, most haven't made it out of the laboratory.

Often it's because the weed-killing microbes can't be kept alive or effective for the long-term. Stabileze (pronounced stable-ease), a new process invented by Agricultural Research Service scientists, could change that.

"Our method uses sugar to stabilize the cell membranes of the organisms," says Paul C. Quimby, Jr. He is a plant physiologist at the ARS Northern Plains Agricultural Research Laboratory in Sidney, Montana. "This approach keeps a large percentage of the organisms alive for 6 weeks to 6 months at room temperature and for at least 2 years under refrigeration," he says.

Now, some organisms can only survive a few hours without the formulation.

The sugar solution and microbes are mixed in a food processor with silica, corn oil, and another ARS invention a water-absorbent starch known as Super Slurper. The mixture forms dispersible granules that can be applied to foliage with conventional spraying equipment. Another plus: the ingredients are cheaper and easier to work with than the sodium alginate and calcium salts that are commonly used to make similar granules.

ARS has received patent application No. 08/695,249 on the process. Quimby developed Stabileze with ARS plant pathologist Anthony J. Caesar; former ARS botanist Jennifer L. Birdsall, who now works for USDA's Forest Service; ARS chemist William J. Connick, Jr.; ARS plant pathologists Clyde D. Boyette and plant pathologist Nina K. Zidack; and plant pathologist William E. Grey, who is at Montana State University in Bozeman.

Ideally, commercial manufacturers and users would like a 2-year survival rate at room temperature, to save on refrigeration costs. But Stabileze is a step in the right direction.  — By Kathryn Barry Stelljes.

USDA-ARS Northern Plains Agricultural Research Laboratory, P.O. Box 1109, Sidney, MT 59270; phone (406) 433-2020

USDA-ARS Commodity Utilization Research Unit, P.O. Box 19687, New Orleans, LA 70179; phone (504) 286-4510

Clyde D. Boyette is at the USDA-ARS Southern Weed Science Laboratory, Stoneville, MS 38776; phone (662) 686-5217.