The seasonal activity of Trachyphloeus bifoveolatus (Coleoptera: Curculionidae) in western Washington

D. A. Barstow, L. W. Getzin


<i>Trachyphloeus bifoveolatus</i> Beck breeds in untended grassland fields and pastures and can be a nuisance pest to nearby homeowners when adults migrate in the fall and spring. This insect is univoltine and overwinters as an adult. Eggs are deposited on the foliage of the host plant during May and June and larvae start appearing in late May. Larvae feed on the root systems of these plants during May, June and July. Pupae are found in small earthen pockets 2- to 5-em below ground from July to mid-August. New generation adults appear in late July and within a month most begin leaving the fields to seek overwintering sites. However, evidence suggests that most of the eggs deposited the following yea are laid by adults that remain in the field over winter. Adults that left the field in the fall apparently do not return to breeding sites in substantial numbers the following spring.


<i>Trachyphloeus bifoveolatus</i>; Coleoptera; Curculionidae

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