This summer many apple trees in the city of Medicine Hat, Alberta, lost their entire crop. The cause? The codling moth, an insect that can devastate an entire apple, pear or walnut crop. Codling moths overwinter in cocoons, which are either under loose bark or at the base of the tree in the soil, or under debris. They emerge as adult moths in early spring. Following mating, females will lay eggs on fruits like apples, where the young bore into the fruit once they hatch.
Once populations are high, they are more difficult to manage by natural controls and pesticides might need to be employed as well to get the population back under control. If using natural methods, it is best to use several at the same time to see any effect.
Photo source: Extension.usu.edu