Attractants for synanthropic flies

Fermented molasses or sucrose solutions are known to attract several species of filth-breeding flies. To identify the volatile attractants produced in fermenting sucrose solutions with yeast, these solutions were fractionated, and the chemical constituents identified and bioassayed against filth-breeding flies includingFannia canicularis (L.),Muscina stabulans (Fallén), andMusca domestica (L.). Distillation of a fermented sucrose solution gave an active distillate and an inactive residue. Gas Chromatographic analysis of the distillate showed the presence of acetaldehyde, ethyl acetate, ethanol, 1-pro-panol, 2-methyl-l-propanol, and 3-methyl-l-butanol. Ethanol constituted by far the greatest proportion of compounds present in the distillate. An aqueous solution of ethanol exhibited the same level of attractancy as the distillate, the fermented sucrose solution, and a reconstituted distillate containing all compounds identified. Ethanol was thus identified as the sole attractant emanated from fermented carbohydrate solutions that elicited positive responses in pest flies, especially inF. canicularis.Diptera: Muscidae.