Monitoring ofDrosophila suzukii(Diptera: Drosophilidae) in Okanagan Valley vineyards, British Columbia, Canada, and assessment of damage to table and wine grapes (Vitaceae)

Abstract

AbstractSpotted-wing drosophila,Drosophila suzukii, (Matsumura) (Diptera: Drosophilidae), has become a serious pest of soft fruit in the Okanagan Valley of British Columbia, Canada since its detection in 2009. The study was conducted to determine the distribution ofD.suzukiiand damage levels in grapes. Apple cider vinegar-baited traps placed in table and wine grape (Vitis viniferaLinnaeus; Vitaceae) vineyards during 2011–2013 demonstrated thatD. suzukiiwas numerous in all sites, with earliest emergence and highest numbers recorded in 2013.Drosophila suzukiiwere reared from intact and damaged table grapes and damaged wine grapes collected from the field, but not from intact wine grapes.Drosophila suzukiiwere reared in low numbers in 2011 from intact fruit of 11 wine grape cultivars exposed artificially in the laboratory. Susceptibility of intact wine grapes under laboratory conditions in 2011 when sour rot was widespread might relate in part to undetected infections of berries due to weather conditions. Identification ofDrosophilaFallén species revealed thatD. suzukiicomprised a small portion of the total. Our results demonstrate that healthy wine grapes in the Okanagan Valley of British Columbia are largely undamaged byD. suzukii, while certain table grape cultivars should be protected from attack.