Pest Control Library: Curculio
Also known as plum curculio, this beetle with the long, curved snout is a common pest of apples, peaches, cherries, apricots, pears, and plums. It is found east of the Rocky Mountains and primarily in the north.
Curculios are diminutive, so they're not easy to spot. You're more likely to see the damage they cause. Initially they make small, circular scars in the skins of developing apples and pears under which they lay eggs. After hatching, the larvae tunnel into the fruits leaving browned and mishapen fruits. Trees often drop the damaged fruit prematurely.
Adult beetles spend the winter hiding among fallen leaves and garden debris. They become active just about the time apples bloom, and that's the most important time to take preventative action.
Prevention and Control
There is no trap or botanical insecticide that will control curculio. You can take advantage of the insect's habit of playing dead when surprised. Each morning for three weeks after petal fall, spread sheets under your fruit trees. Shake or jar the tree, and the beetles will fall onto the sheets where you can collect and dispose of them.
Pick up and destroy all fruit that falls to the ground. This step alone will diminish a curculio population substantially.
Some gardeners use the organophosphate insecticide phosmet (Imidan) to control curculio. Compared to other organophosphate insecticides it does not persist long in the environment. However, it is toxic to honeybees -- do not use it when pollinators are active.
Photography by Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org