The Efficacy of Sake as a Trap for Spotted Wing Drosophila

On occasion, we do run across ideas on how to improve our current efforts in developing a decent control regime for the spotted wing drosophila.

The use of sake ("rice wine", correctly pronounced as sa-KKE, not saki) as a trapping medium is one of those ideas.  Initially mentioned in the groundbreaking Kanazawa paper from the 1930's, it was also the subject recently of a short program on NHK (Japan Broadcasting Corporation) on managing vinegar and other flies in the household.
With the generosity of Patrick Kingston, replications of this sake trap (200 ml vinegar, 100 ml sake, 3.5 oz sugar and dubbed the "sake bomb")  were tested in the same raspberry field as the standard yeast sugar water (0.25 oz yeast, 4 tsp sugar, 300 ml water) trap.  As one can instantly see from the chart below, this trap is not as effective as the yeast sugar water trap.  Interestingly, there does seem to be a trend in the yeast sugar water trap depending how close it was placed to a potential source of a lot of spotted wing drosophila, a sensitivity not apparent in the sake trap.

Of interest, however, is the fact that the "sake bomb" was quite effective, much more than the yeast sugar water trap, in drawing in some six other species of flies, including houseflies.  This could be useful information in the case of future infestations of exotic flies.