New Chemistry on the Farm

ECONOMIC, health, and environmental concerns are slowly prying farmers away from their long dependence on agricultural chemicals - pest killers, weed killers, and various other compounds used to enhance the size and appearance of crops. The well-publicized flap over Alar, a ripening agent used on apples, will do its part to hasten the process. While worries about chemical residues have sometimes been exaggerated - and scientific opinion about their danger is anything but unanimous - the move toward more moderate use of chemicals in food production makes sense. Extensive pollution of ground-water reserves, in itself, is reason enough to reconsider farming methods tied to automatic heavy doses of herbicides, commercial fertilizers, and other chemical compounds. The health risks associated with dozens of pesticides simply force the issue.

Apple growers and processors have agreed voluntarily to stop using Alar, after experiencing a 20 percent drop in sales since the issue surfaced on TV's ``60 Minutes.'' Makers of applesauce and apple juice have urged the Environmental Protection Agency to put an outright ban on Alar, hoping that would reassure the public.

California, with its huge farm sector, is launching a ``quality assurance'' program. Growers who pledge to follow guidelines for pesticide application, and agree to underwrite additional testing for residues, will be able to slap a ``quality'' seal on their produce.

Consumer advocates sneer at the idea, arguing that it wouldn't do anything to cut back on actual pesticide use.

But a cutback, slow though it may be, is taking place. Advances into a new era of reduced chemical reliance are unmistakable. So-called integrated pest management is being applied more widely. It includes closer monitoring of insect populations and greater care in the application and choice of pesticide, among many other techniques. Crop rotation and introduction of insect species that prey on pests have a role, too.

Large chemical companies, as well as smaller research outfits, are turning to biotechnology to devise ``natural'' pesticides that use bacteria or spores to attack pests. One product uses ground-up crab shells to nourish a microorganism that preys on harmful nematodes. Genetically engineered crops will carry their own toxins, harmless to humans but deadly to insect pests.

These approaches and others suggest that the current $5 billion a year spent on agricultural chemicals can be reduced. Farmers are well aware of the cost burden of pesticides, as insects become immune to the poisons and ever larger doses are needed.

For now, heavy reliance on chemicals remains an agricultural orthodoxy - believed crucial to high yields and attractive products.

But free thinkers are on the move - from those who are using fewer chemicals with more precision and care to the organic farmers who reject them altogether. Ultimately, consumers who find their produce more desirable will force others to follow.