OVERWINTERING BY THE BOLL-WEEVIL (COLEOPTERA, CURCULIONIDAE) IN CONSERVATION RESERVE PROGRAM GRASSES ON THE TEXAS HIGH-PLAINS

Scarcity of suitable overwintering habitat is a major obstacle to the establishment of the boll weevil, Anthonomus grandis grandis Boheman, in cotton-producing counties of the Texas High Plains (THP). After introduction of the Conservation Reserve Program (CRP) in 1985, a 3-yr study was conducted to investigate the overwintering potential of the boll weevil in two CRP grass habitats on the THP. Overwintering survival of the boll weevil in leaf litter of sand shinnery oak, Quercus havardii (Rydberg), in the Texas Rolling Plains (TRP) served as a comparison. CRP grasses provide marginal over-wintering habitat when compared with sand shinnery oak leaf litter. For a given level of winter severity, total winter survival and effective emergence (emergence after approximately 15 June in the study area) were consistently lower in the CRP grasses than in sand shinnery oak leaf litter. Even with lower survival rates in THP grasses, economically damaging boll weevil infestations could follow mild winters if large diapausing populations develop in the fall. Pheromone traps located in CRP pastures on the THP indicated a relatively low level of overwintered boll weevil emergence during all three study years.