The biology of Paropta paradoxus (H.-S.), a new pest of the grapevine, was studied in field and laboratory during 1962–1972. Descriptions are given of the imago and developmental stages. The life-cycle is completed in 1–3 years. Adults are active during April–September, and eclose mostly during the day with a male/female ratio of 0.65 (3.3 in UV light-trap catches). Light induces a deep torpor in most adults. After mating, which lasts 30–60 min, females lay up to 275 eggs in their life span of 1–14 days (males 2–13 days). In the vineyard eggs are glued under loose bark, in batches of 15.6 (1–63), and hatch in 20–32 days. The neonate larvae disperse and settle under loose bark where they begin feeding; penetration of the wood is mainly through dried stubs of pruned canes, and galleries are excavated along the axes of stems and branches. Larvae may also develop under dry bark. The pest overwinters as active immature larvae and diapausing mature, prepupal larvae. The pupa is usually formed in the larval galleries, and lasts 16–45 days. In heavily infested vines the pupae may be cannibalized by larvae; both larvae and pupae may be preyed on by woodpeckers.
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