Newly hatched larvae are about 1 mm long, full grown larvae reach a length of 7-9 mm. Adult plum curculio. The plum curculio overwinters as an adult under leaf debris of deciduous trees, brush piles and stacked cordwood near or adjacent to orchards, but not generally in the orchard. Emergence from overwintering sites continues for three to four weeks, peaking around the petal fall period. The beetle migrates to orchards by crawling or flying using olfactory and visual cues.
Female beetles begin laying eggs several weeks after emergence.
Early varieties with dense foliage and yellow-skinned cultivars are most heavily attacked. The eggs hatch into larvae that feed inside the developing apples. Some fruit will drop prematurely but larvae continue to develop inside these fruit. In fruit that remain on the tree, the larvae do not always successfully mature, since the rapidly expanding fruit may crush the larvae. Plum curculio egg.