Your Classic Apple Orchard

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CONTROLLING INSECT PESTS

The codling moth, the classic worm in the apple, is the worst insect pest in most areas. If the moths are emerging from your trees—not flying in from neighbors' trees—you can reduce the overwintering generation by wrapping corrugated cardboard strips around apple and pear trunks in late summer, before the worms crawl out of the fruit and down the trees to hibernate. The corrugated cardboard will seem like a fine hibernating place, and over the winter woodpeckers will pick out many of the worms and eat them. In late winter or very early spring, remove and destroy the cardboard, along with any remaining worms and pupae.

The hibernating worms pupate in late winter, emerging as moths soon after budbreak. You can trap many of these moths—even if they're flying in from outside your property—in buckets containing one part yeast, two parts honey or molasses, and six parts water. If codling moths are still numerous, spray with ryania or phosmet (Imidan) at petal fall and again 10 to 12 days later. (Ryania is an insecticide derived from a plant and thus considered "organic." Phosmet is synthetically produced but actually less ecologically damaging; it's much more effective against several key apple pests, yet very easy on beneficial insects.) In the North, where the codling moth has only one generation per year, that's all the control you'll need.

Here in Kansas, where the codling moth has three generations per year, we control the first and heaviest generation with these two sprays, and the second and third generations with beneficial Trichogramma minutum wasps. These wasps live longer and provide better control because of the availability of abundant nectar and pollen from flowers I planted under and near the apples and pears. Flowers in the carrot (dill, caraway), mustard (alyssum, rock cress) and daisy (yarrow, black-eyed Susan, coneflowers) families are especially helpful in attracting beneficial wasps.

A new, no-spray way to combat codling moths, in orchards of five acres or larger, is mating disruption. Pheromone-impregnated plastic ropes, similar in size and shape to twist-ties used to seal bread bags, are hung near the top of each tree just before the first moth flight (around bloom) and again just before the second moth flight. These pheromone dispensers give off a blanket of scent, like that of female moths, confusing the male moths so that few are able to locate and mate with the females. Egg-laying—and the resulting worm damage—is greatly reduced.

In orchards of one acre or larger, mating disruption with a different pheromone provides excellent control of the oriental fruit moth. This worm looks like a codling moth but is slightly smaller, and tunnels throughout the fruit. This pest has done more damage in some regions (such as Arkansas and Kansas), especially late in the season, than has the codling moth. Trichogramma wasps help control it, but extra releases are needed later in the season.

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