Are Yeast Autolysate Attractants for Ceratitis Species (Diptera: Tephritidae) in South Africa More Attractive and Palatable Than a Currently Used Protein Attractant?

Due to increasing usage of copper fungicides in citrus orchards shortly before the application of protein baits for fruit fly control and the risk of this combination causing fruit phytotoxicity, an investigation of attractants containing higher amounts of yeast autolysate rather than protein hydrolysate was conducted. A commercial yeast autolysate from Australia was less attractive than a South African product HymLure (with a mixture of autolysate and hydrolysate) to three Ceratitis species: Ceratitis capitata (Wiedemann), Ceratitis rosa s.s. Karsch, and Ceratitis cosyra (Walker). Other custom-formulated autolysates were also inferior to HymLure for these species. Consumption of autolysates during the first hour of feeding was similar to that of HymLure. The inferior attraction of these three species of fruit flies to autolysates, relative to one containing hydrolysate, did not warrant further investigation of autolysates for use in baits to control these quarantine pests.