Epitaph for a Peach by David M. Masumoto Page B

Chemical particles become suspended in the air and ride the air currents. Our valley is susceptible to this kind of acid fog that drifts from field to field. I conjure overblown images of radioactive clouds rolling across the countryside, hovering above children in school playgrounds, marching toward suburban tracts. The study proved our sprays don’t stop at property lines. Suddenly what a neighbor might do affects you more than you imagined. Having good neighbors is more important than ever.
    Damage from peach twig borer occurs inconsistently. I’ve seen years when spray programs didn’t work and my neighbors scratched their heads wondering why. I’ve also heard pest control advisers who sell farmers their chemicals explain the damage with the claim, “It was a wormy year.” No one has proven that borers have developed a resistance to chemicals, but I’ve learned never to underestimate the ability of pests to adapt.
    Bill, a friend and University of California researcher, is developing a new method to attack peach twig borers. He is a veteran of many years of battles, having seen the industry change with the deluge of new chemicals and sprays that have been developed since World War II. In the late forties and fifties, the nation shifted a wartime industrial complex from the European and Pacific fronts to my farm. I can imagine the nation’s consciousness: “We beat the Germans and Japanese, why not go after insects next?”
    Bill is exploring a novel idea: Why not use a less toxic treatment on the peach twig borer? Not fewer sprays but different ones. He advocates using a bacterium called Bacillus thuringiensis, or BT for short. Worms eat the BT and die, but the poison is very selective, leaving natural enemies and people unharmed. The major problem with these bacteria is their short life—they last only a few days in the field. Timing is therefore crucial. The spray must be applied precisely when the caterpillars are emerging.
    I picture the peach twig borer making a mad dash for a green shoot, and in that window of opportunity I must apply my BT spray. It would be like those hundreds of little turtles that hatch and make a mad dash for the ocean, only to be snatched up by gulls and other critters. Must I be a gull, hovering above the beach front, patiently waiting for the hatch? Timing like that doesn’t seem possible.
    But Bill has a plan: spray early in the life of a peach twig borer while they’re still young and much more vulnerable to a minute amount of poison. The idea is to use BT before the peach shoots are very long, when the worms are feeding on small leaves. Also BT will last a little longer in the cooler spring weather, when there are fewer leaves to coat with the bacteria and the worms are more exposed. Bill’s plan is to lengthen the beach, so to speak, to shift the odds in favor of the farmer. But I will still have to time the spray with the hatch.
    A realization: I don’t understand the life cycle of the peach twig borer. For years I have killed it without thinking. But if I hope to raise my peaches organically and battle pests differently, I need to learn more about the life in my field, including the pests. I have never seen a peach twig borer infant worm. I hear they hatch in the tops of trees and somehow crawl to their first meal. But no farmer I know has ever seen a newborn borer.
    Pat, a graduate student from the University of California at Berkeley, was completing his doctorate in entomology. We became friends and talked for hours about politics and farming. Walking through my orchards I often joked about our height differences; he was almost a foot taller. I claim that, at six feet four inches, Pat can see into the trees much more easily than I can, literally providing a different perspective on my peaches. His dissertation subject: “Peach Twig Borer.”
    We slip into hour-long conversations about this worm. I ask questions only a