Acrobasis vaccinii

Larvae can be identified by their green coloration with brownish-red dorsal markings and their presence inside damaged berries, where they leave characteristic frass. Adults are small moths requiring dissection or genitalia examination for definitive identification from related Acrobasis species. Eggs are minute, flat, white, and scale-like, requiring hand lens magnification to detect in calyx cups.

Adults have a wingspan of 16–18 mm. Larvae are mostly green with brownish-red pigmentation on the dorsal surface, reaching approximately half an inch (12–13 mm) before pupation. Eggs are flat, white, scale-like, and deposited on or within the calyx cup of berries.

Found in commercial and wild stands of Vaccinium species, including cultivated blueberry and cranberry bogs. Occupies environments where host plants flower and fruit, from early season through harvest.

Native to eastern North America from Nova Scotia to Florida and west to Wisconsin and Texas. Introduced to Washington State.

Adults emerge after full bloom and fruit set. One generation per year. Larvae present during fruit development; full-grown larvae overwinter in cocoons.

Larvae feed internally on developing fruits of Vaccinium corymbosum (highbush blueberry), Vaccinium macrocarpon (cranberry), Vaccinium vitis-idaea (lingonberry), and Vaccinium stamineum (deerberry). Each larva consumes the contents of multiple berries, typically 4–8, to complete development.

• Vaccinium corymbosum - larval hosthighbush blueberry
• Vaccinium macrocarpon - larval hostcranberry
• Vaccinium vitis-idaea - larval hostlingonberry
• Vaccinium stamineum - larval hostdeerberry

One generation per year. Eggs laid on unripe berries. Larvae feed internally on berry contents, moving between fruits. Full-grown larvae exit berries and overwinter in silken cocoons in leaf litter or soil. Pupation occurs in spring, with adult emergence timed to host plant bloom and early fruit development.

Females oviposit preferentially on or within the calyx cups of unripe berries. Laboratory studies indicate females may prefer larger fruits when available, though field studies show no discrimination between fruit sizes within patches, possibly due to competition for early-season oviposition sites. Larvae feed concealed within berries, tunneling between fruits as they develop.

Primary fruit pest in cultivated Vaccinium systems. Larval feeding reduces yield and fruit quality. Serves as host for parasitoid wasps including species in genus Mesostenus (Ichneumonidae).

Major economic pest of blueberry and cranberry production. Management relies on pheromone trapping (ISCAlure-Vaccinii) to time insecticide applications, manual removal of infested berries, and inspection of calyx ends for eggs. Multiple insecticide classes are labeled for control, with increasing use of selective materials to preserve natural enemies.

• Acrobasis nuxvorellaPecan nut casebearer; similar size and family but feeds exclusively on pecan (Carya illinoinensis), with distinct forewing markings including a ridge of dark scales
• Acrobasis stigmellaAnother Vaccinium-feeding Acrobasis species; requires genitalia dissection for definitive separation from A. vaccinii

• pest
• agricultural pest
• Vaccinium pest
• fruit borer
• monophagous
• univoltine

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Pecan Nut Casebearer: New Guide Provides IPM Options
• Bug Eric: Wasp Wednesday: Mesostenus
• Bug Eric: A Potential New Host Record for Calliephialtes grapholithae (Hymenoptera: Ichneumonidae) from a Paper Wasp nest (Hymenoptera: Vespidae: Polistes metricus)
• A Color Variant of Cranberry Fruitworm, Acrobasis vaccinii, and Host Records of Acrobasis amplexella (Lepidoptera: Phycitidae)
• Is fruit size important in the selection of oviposition sites by cranberry fruitworm, Acrobasis vaccinii?