OSU scientists test a new generation of pesticides

August 17, 2005

AURORA - Next year, the U.S. Department of Agriculture will end a 10-year examination of pesticides used in the United States, and many highly toxic, broad-spectrum chemicals will be phased out.

Bob McReynolds, Oregon State University Extension agent for vegetable production, is part of that process. McReynolds' goal is nothing less than to replace a generation of powerful chemical agents related to World War II nerve gas with less environmentally harsh pesticides.

Terminating the use of potent, broad-spectrum pesticides is safer for people and other non-target organisms, but it can be tough for business. The potential sale of a pesticide to protect, for example, turnips from turnip aphids may not cover the costs of testing for safety and environmental effects required by U.S. law.

So when turnip growers need a safe and effective product to control aphids, they turn to McReynolds at OSU’s North Willamette Research and Extension Center for help.

McReynolds runs the Minor Use Program at the center, administering carefully controlled field tests of pesticide residue on Willamette Valley crops from blueberries to hops. These so-called minor crops are major contributors to Oregon’s economy. They represent most of the crops grown in the valley, with a net value of $1.4 billion, 68 percent of Oregon’s total crop value.

McReynolds’ work is part of the U.S. Department of Agriculture’s Interregional Project No. 4 (IR-4), a program to help producers find safe and effective pest management tools for minor crops.

“We provide the research required by the Environmental Protection Agency to label pesticides for crops that are generally too limited in scale to be profitable for pesticide manufacturers to research,” McReynolds said.

A generation ago, pesticides were developed to target a wide range of pests. Not anymore. Today’s pesticides are very specific to a particular pest on a particular crop at a particular time.

The goal of the IR-4 program is to replace compounds of chlorinated hydrocarbons and organophosphates with safe and effective chemicals that are less toxic to off-target organisms. Much of IR-4 research focuses on reduced-risk chemicals and biological controls. IR-4 supported the registration in the 1970s for many of the natural pesticides used today by organic growers.

“Compared to old pesticide products that were applied in pounds per acre, new products are applied in ounces per acre,” McReynolds said.

To meet EPA standards for pesticides used in or on foods and animal feed, each active ingredient must be tested for human safety and environmental effects as well as its effectiveness on crops. The value of major crops such as corn and soybeans can offset the cost of research necessary to determine the safest, most effective pesticides. Growers of minor crops can rarely afford such studies on their own.

McReynolds’ process begins with a problem. Say, a weed is smothering a crop of asparagus or a disease is shriveling carrots. There are lots of possible solutions, a whole toolbox of integrated pest management methods that must be tested to see if they are both safe and effective.

“Once the manufacturer confirms that the pesticide is safe for humans and the environment, we perform a battery of tests to determine if it is effective against a particular plant pest or disease,” McReynolds explained. “If the pesticide is found to be both safe and effective, then our final tests measure the level of pesticide residue that remains on the crop after harvest.”

In the past couple of years alone, nearly 25 new pesticide registrations have been granted for use on particular minor crops grown in the Willamette Valley.

“Pest management is not done on a whim,” McReynolds said. “It’s done to provide quality products to consumers.”

Author: Peg Herring
Source: Bob McReynolds, Joe DeFrancesco