Trapping spotted wing drosophila, Drosophila suzukii (Matsum- ura) (Diptera: Drosophilidae), with combinations of vinegar and wine, and acetic acid and ethanol

The spotted wing drosophila (SWD), Drosophila suzukii (Matsumura), is widely distributed in temperate and subtropical Asia (Delfinado and Hardy 1977) and has recently been found in the eastern United States and western North America (Steck et al. 2009; Walsh 2009; Beers et al. 2010). The fly is of concern to fruit growers because of its ability to attack ripening soft fruits. It is considered to be a threat to the production of berries, cherries, grapes and other fruits. Presently, programmes are in place to detect and monitor the presence and relative abundance of the fly throughout much of the fruit production regions of California, Oregon, and Washington of the United States, and British Columbia, Canada, to determine the presence and rate of spread of SWD, as well as to assess its threat to the fruit production industries in these areas. As a part of these programmes, traps are maintained following recommended trap and bait designs and trapping protocols. These recommendations include the use of apple cider vinegar or grape wine as the bait in traps (Steck et al. 2009; Beers et al. 2010). The trapping of male and female SWD with baits may have potential for management or control of SWD through attract and kill or mass trapping approaches, as shown by Kanzawa (1934). Although both bait types in use are successful in luring SWD to traps, improvements to the lure might improve detection efforts if those improvements significantly increase trap sensitivity and might improve trap efficacy in ‘trap out’ or mass trapping attempts for control of fly populations. Identification