The Reemergence of an Old Pest, Orchestes pallicornis (Coleoptera: Curculionidae)

Apple flea weevil, Orchestes pallicornis (Say) was a sporadic pest in the early 1900s and has reemerged as a severe pest of cultivated apple ( Malus domestica Borkh.) in Michigan. Organic apple orchards in Michigan have had outbreak population levels of apple flea weevil since 2008 and damage has resulted in up to 90% losses. Apple flea weevil is a small, 2–3-mm black weevil with enlarged high legs for jumping. The adults feed on bud and leaf tissue and heavy pressure causes bud termination. Leaf tissue is removed in multiple small circles, with the net result of the large removal of photosynthetic material. Larvae are leaf miners, developing between the upper and lower leaf cuticles while migrating from the midrib to the leaf margin where pupation occurs. Pupae develop inside a blister, an air-filled space that turns brown. Low populations of apple flea weevil are missed easily or misdiagnosed as either frost damaged from bud feeding or sulfur burn from pupal cases. Apple flea weevil is likely secondarily managed by broad-spectrum insecticides used in conventional programs. However, there are currently no proven management options for use in organic production. As broad-spectrum materials are replaced by reduced-risk compounds, it is possible that apple flea weevil will become an important pest in apple production.