Ridding Fruit Trees of Menacing Larvae

Buried deep in our primitive brain are sensitive corners that respond below the radar of our consciousness to a host of subtle signals. We are not alone in our response to pheromones and other chemical signals. Insects respond to minute quantities of scent from plants that supply them with food or nesting sites. Major chemical cues for mating are also produced by the opposite sex of many species. This proclivity to search out that alluring cue can be manipulated to the gardener’s advantage.

The coddling moth lays its eggs on apple trees in the spring, and larvae crawl onto the fruit and burrow in. If you’ve ever bitten into a “wormy” apple, you know how much damage they can do. After ruining the apple (they also like pears), the larvae spins its cocoon and metamorphoses into another moth. There are a couple ways to break this cycle and rid your orchard of this pest. The first is to monitor your fruit and remove any with signs of worms. Disposing of them before they can crawl out to lay more eggs can help a lot.

One other aid employs a pheromone-a sex attractant-that draws the male moth. The pheromone is applied, along with a sticky coating, to small cardboard traps. These devices, looking like miniature pup tents, can be hung in apple trees to lure male moths to their demise. No males, no fertilized eggs, no more moths. The traps last for several months, but placing them at the right time is crucial. Moth larvae are beginning to emerge in March in California, so now is the time to catch them. Use one trap to monitor the presence of the moths so that you can find the larvae-ridden fruits in a timely manner or place three in each tree to capture the majority of the moths. It may take several years of consistent monitoring and trapping to rid your orchard of coddling moths, but a little effort this month will pay off at harvest time when your apples and pears are worm-free.

March Tips

• Now is the time to give evergreen shrubs that form hedges and foundation plantings, such as pittosporum and boxwood, a serious pruning to bring them back into shape. Light shearing throughout the rest of the year will bring them back to this basic size and structure.

• Don’t neglect to thin fruit as it develops. Results in terms of individual fruit size will amaze, and it relieves stress on tree branches, minimizing breakage.

• Snails, slugs, and aphids are the first pests to arrive in spring, so keep a sharp eye out to deal with outbreaks early, before they do too much damage.