Species Conotrachelus nenuphar - Plum Curculio

Conotrachelus nenuphar (Herbst)

Orig. Comb: Curculio nenuphar Herbst 1797

4.5-6.5 mm (1)

Det. M. A. Quinn, 2013

e NA (TX-FL-QC-BC) -Map (2)(GBIF)

mostly: Apr-July (BG data)

a common pest of many fruits throughout Minnesota, including plums, cherries, apricots and other soft fruits. It can damage apples, although the damage is often only superficial. If feeding and egg-laying damage are slight, due to a low population of these weevils, there may be no need to control plum curculio in home apple plantings. However, in some orchards, damage from plum curculio leads to a large percentage of fruit that is unattractive and sometimes inedible. Late-season plum curculio feeding may also open wounds that will later be exploited by multicolored Asian lady beetles. - University of Minnesota

Plum curculio adult females lay eggs on apple fruitlets, but the larvae cannot grow and develop in the hard, expanding flesh. You will never find a live plum curculio larva in an apple at harvest, nor will you find extensive internal feeding damage caused by a curculio larva. However, plum curculio activity can cause premature fruit drop. If an apple drops early in the season, the flesh softens, and a curculio larva can finish its development. (The larvae often develop to maturity in soft fruits such as plums and cherries.) - University of Minnesota

The adults hibernate through winter and emerge to feed on tender foliage, buds, and blossoms. Later they attach the newly set fruit, cutting small circular holes through the skin. Females make crescent-shaped punctures for egg laying. The egg is deposited under the skin, hatches into a very small whitish grub, which moves to the fruit's flesh. In 12-18 days, the larva bores out of the fruit and enters the soil, forming an earthen cell in which to pupate. Pupation is 3-4 weeks.(1)

Effective non-chemical controls for plum curculio have not yet been developed. If this insect is more than a nuisance in your planting, you can try sanitation and shaking or beating the branches, but these methods probably won’t be sufficient, and you will probably need to spray an insecticide. - University of Minnesota

University of Kentucky