Oviposition patterns of the strawberry bud weevil (Coleoptera : Curculionidae) at two spatial scales and implications for management

The strawberry bud weevil, Anthonomus signatus Say, is an important pest of strawberries in eastern North America. Typically, growers treat entire fie lds with insecticides on an annual basis when the number of clipped buds ex ceeds a threshold. The 3 objectives of this study were as follows: (1) to d etermine the distribution of weevil injury within strawberry fields, (2) to determine if managing only held borders would be effective, and (3) to det ermine if weevils preferentially oviposit in particular orders of flowers o n an inflorescence. During a 3-yr monitoring period (1992-1994),A. signatus oviposition activity increased unidirectionally at a rate of approximate t o 8 m or 10 rows (1.25 m centers) per year. In 7 grower fields in New York, only the 12-m perimeter of strawberry fields treated with insecticide redu ced injury to a level similar to interior portions of the field. In the int erior of these fields, insecticide treatments did not influence the level o f weevil damage. Even when weevils damaged floral buds, only a small propor tion (7%) were primary flowers that produce the largest fruit. On average, oviposition occurred disproportionally in secondary newer buds. These obser vations indicate that A. signatus can be managed effectively by treating th e outside perimeter of fields rather than entire fields, planting cultivars that compensate the most for clipper injury on the perimeter, and suggest that thresholds could be raised because damage to large, primary buds is li mited.