The Plum Curculio is one of the most damaging insect pests that attack tree fruits. It can be particularly destructive, and damage intensified where stone fruits and apples are interplanted. Damage is done when the overwintering adult beetles attack the fruit and eat holes through the skin to feed on the pulp. In addition, the females make distinctive, crescent-shaped wounds on the skin when laying eggs. Plum curculio is capable of causing great damage and is considered a difficult pest to control.

The life cycle starts when temperature and moisture conditions are favorable in the early spring. The overwintering adults leave their hibernation quarters in trash on the ground, woodlots or hedgerows, and migrate to the trees. This usually occurs just about the time of bloom.

After mating, the female deposits eggs into the fruit. Each female is capable of laying from 100 to 500 eggs. The incubation period for the eggs is about one week. The young larvae bore to the center of the fruit, where they feed until reaching maturity.

Plum curculios are a type of weevil and have a pronounced snout. They range in size, but are not larger than the top of a pencil eraser. They are plump and bumpy with a black area in the center of its back.

Control of plum curculio is mainly limited to chemical sprays at the petal-fall and shuck-split stages. That is where we are now in some stone fruit. We have had reports of activity already this season. However, any warm weather will really bring them out. Guthion, Imidan, Calypso, and Avaunt are considered to provide excellent control. Other pesticides only provide good control. Homeowners may want to try Surround – an organic clay particle product to achieve partial control.

That is all for today, this has been Al Gaus for Michigan State University Extension in Berrien County.