Attractive Effect, Active Components, and Behavioral Mechanisms of Four Rotten Host Fruits for Drosophila melanogaster Meigen and Control Efficacy in Field

Drosophila melanogaster Meigen has become a major threat to fruit crops. Decayed banana, bayberry, blueberry, and strawberry strongly attracted D. melanogaster after 60 days, with banana highest (69.17%). Thirteen compounds from the fruits (GC–MS analyzed) were tested for attraction to the adults; five (ethyl linoleate, γ-decalactone, n-decanoic acid, tetradecanoic acid, and ethyl palmitate) were active attractants. Ethyl linoleate reached an attraction rate of 54.43% at doses of 0.01 mg. The combination of ethyl linoleate + γ-decalactone exhibited the highest attraction rates, reaching 25.40% at 0.01 mg and 26.06% at 0.005 mg. Rotten fruits elicited strong electrophysiological (EAG) responses, unlike single/combined compounds. Highest values were: rotten banana 26.39/24.78, ethyl linoleate 1.79/1.30, ethyl linoleate + γ-decalactone 2.29/1.35 (♀/♂). Docking showed ethyl linoleate bound three Odorant-Binding Protein (OBPs) most strongly, while Lush had the strongest overall affinity. This work identifies the attractants in rotten fruits and provides a basis for designing new insect attractants.