House fly attractants based on constituents of blackstrap molasses

Blackstrap molasses is known to be a powerful attractant for adult house flies (Musca domestica). In previous work, chemical analysis of molasses and bioassays demonstrated that flies are attracted to aqueous solutions of some combinations of the following constituents of chemicals found in molasses: propionic acid, benzoic acid, 2, 6-dimethoxyphenol, 2-acetylpyrrole, 2-hydroxy-3-methyl-2-cyclopentene-1-one, 2-methyltetrahydrofuran-3-one, and 3-methylbutanal. In the present study, we first developed a bioassay method that involves comparing fly responses to candidate blends by releasing 1000 flies into large rooms containing Captivator traps baited with filter paper treated with 3 ml of candidate attractants. Initial assays indicated that propionic acid, the major component, is attractive at low concentrations (3%) but highly repellent at higher levels. One candidate blend is comparable in attractiveness to the industry standard Starbar (Farnam) commercial fly attractant. Unlike the commercial product, the candidate blend has a mild odor to humans with notes of vinegar and fruitiness. Work is in progress to further optimize the blend and perhaps improve performance by the addition of z-9-tricosene.