Anthonomus rubi on Strawberry Fruit: Its Biology, Ecology, Damage, and Control from an IPM Perspective

SIMPLE SUMMARY: New damage on fruit caused by Strawberry Blossom Weevil (SBW) adults has been found in recent years in strawberry fields (soilless system under tunnel) in Trento Province, north-east Italy. According to this new scenario, studies on the biology, ecology, monitoring tools, and potential control methods for SBW were conducted to develop Integrated Pest Management (IPM) strategies. We observed the presence of SBW adults in strawberry fields all year round. In April, the young transplants are promptly visited by SBW adults. The first strawberry severed buds appear immediately after the development of the first flower trusses. Then from May until late October SBW damages the fruit. The mass trapping technique, using the green bucket traps baited with synthetic attractant, showed unsatisfactory results. In contrast, the same attractant combined with yellow or green sticky traps showed good efficacy in capturing adults. The high temperatures provided by the black fabric, the periodic removal of severed buds or adults and the Chlorpyrifos-methyl application constrained pest population build-up effectively. Our observations provide clarification of the new additional feeding habits of SBW and are fundamental in developing IPM strategies. ABSTRACT: The strawberry blossom weevil (SBW), Anthonomus rubi, is a well-documented pest of strawberry. Recently, in strawberry fields of Trento Province (north-east Italy), new noteworthy damage on fruit linked to SBW adults was observed, combined with a prolonged adult activity until the autumn. In this new scenario, we re-investigated SBW biology, ecology, monitoring tools, and potential control methods to develop Integrated Pest Management (IPM) strategies. Several trials were conducted on strawberry in the laboratory, field and semi-natural habitats. The feeding activity of adult SBW results in small deep holes on berries at different stages, causing yield losses of up to 60%. We observed a prolonged survival of newly emerged adults (>240 days) along with their ability to sever flower buds without laying eggs inside them in the same year (one generation per year). SBW adults were present in the strawberry field year-round, with movement between crop and no crop habitats, underlying a potential role of other host/feeding plants to support its populations. Yellow sticky traps combined with synthetic attractants proved promising for both adult monitoring and mass trapping. Regarding control, adhesive tapes and mass trapping using green bucket pheromone traps gave unsatisfactory results, while the high temperatures provided by the black fabric, the periodic removal of severed buds or adults and Chlorpyrifos-methyl application constrained population build-up. The findings are important for the development of an IPM strategy.