Efficacy of various attractant baits and lures for monitoring Drosophila suzukii (Diptera: Drosophilidae)

Monitoring pest populations is a key component to many Integrated Pest Management programs.  When Drosophila suzukii (Diptera: Drosophilidae), or spotted wing drosophila (SWD), first arrived in North America, these flies were trapped using various plastic containers baited with apple cider vinegar (ACV).  While ACV was a reasonably effective bait, it also caught several thousands of other insects (known as bycatch) each week.  To improve sensitivity (earlier capture of SWD in the season when densities are low), and increase specificity (reduce unwanted bycatch), new synthetic lures have been manufactured explicitly for capturing SWD.  We tested commercially produced lures against several standard baits, including ACV and yeast bait, in traps made from plastic jars.  Synthetic lures were tested using either ACV or water as the drowning fluid.  Traps were deployed in early June, and trap contents were retrieved and drowning fluid was replaced weekly until October.  Trap captures were evaluated for male and female SWD, and other Drosophila.  The two commercial lures performed similarly and caught the higher numbers of flies when densities were low.  Lures used with ACV caught greater numbers of SWD only in later months, when SWD densities are highest.  However, using ACV as a drowning fluid with lures also increased the number of other Drosophila in the traps.  Yeast bait, ACV, and wine-vinegar baits did not perform as well as the synthetic lures.