Q. How do I know whether my apple trees (and the apples) are damaged by apple maggot or codling moth? Nancy Pearson – Lakewood, WA
A. The easiest way is to look at the damage. You’ll need to cut the apple in half (yuk) and then look at the feeding pattern. Apple maggot larvae are about half the size of the codling moth larvae. That is relative to the size of the adults since apple maggots are quarter inch flies and the codling moth larvae is about half an inch. Apple maggot flies lay their eggs randomly on the fruit. They stick their ovipositor just below the skin of the fruit to lay their eggs. The eggs hatch out and feed randomly in the fleshy regions of the fruit making tunnels. Codling Moths lay their eggs somewhere on or near the fruit and the larvae hatch and usually enter the fruit at the base and eat along the core (feeding on the core and the developing seeds). Once you know the culprit you can start a monitoring and control system. There are traps available for the adults of both species. The apple maggot traps use the enticement of “food” to trap adults, which I have mentioned in past articles. The Codling moth traps use the promise of sex in the form of a synthetic pheromone that traps male moths. Trapping isn’t 100% effective control so you will need to use these to both control the population and monitor other control methods. Both species return to the soil to pupate to adults so this is a vulnerable stage as well. Keeping infected apples from falling and laying on the ground will help control both, but a sticky band around the trunk of the tree is advisable because in addition to hitching a ride with a fallen fruit the codling moth larvae may sometimes exit and crawl down the trunk of the tree to the soil. Beneficial nematodes can be used to control larvae of both species that are in the soil and I think there is some promise in neem soil drenches that are now being registered for various soil grubs and larvae.