Feeding, oviposition and emergence of the white pine weevil (Pissodes strobi (Peck)) under a pioneer broad-leaved forest canopy

Abstract

The white pine weevil's (Pissodes strobi Peck) feeding, oviposition and emergence were studied in a 12-year-old (1998) white pine (Pinus strobus L.) progeny test established under a canopy of mature pioneer species in the Outaouais region (Notre-Dame-du-Laus, Québec, Canada). The basal area of the overstory centred on 63 white pines was used as an indicator of forest cover. With overstory basal area ranging from 0 to 16 m2/ha, some white pine weevil performance parameters such as feeding and oviposition were significantly correlated with forest cover. However, others like the number of pupal chambers, emergence holes, partial survival index (emergence holes/chip-cocoon punctures) and total survival index (oviposition punctures/emergence holes) were not. Results showed that with an increase of forest cover, tree height was not affected but tree bole diameter was reduced. No relation was observed between leader diameter and the number of oviposition punctures. Even under a canopy, natural enemies (Lonchaea corticis Taylor and hymenoptera parasitoids) were also noted to reduce larval and pupal white pine weevil populations. Key words: white pine weevil, white pine, undercover plantation, natural biological control, oviposition, feeding, emerging population, overstory basal area