Evaluation of synthetic oviposition stimulants to enhance egg collection of the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

Tephritid flies are pests of horticultural importance throughout the globe. The oriental fruit fly, Bactrocera dorsalis (Hendel), is particularly feared because it attacks many commercial fruits and vegetables causing huge economic losses. The sterile insect technique (SIT) can be an effective, target-specific and economically feasible control method. However, implementation of SIT depends on mass production of high-quality insects. Production of superior quality eggs is of foremost importance in insect mass production. However, present protocols make use of fruit juices or fruit domes that attract saprophytic insects or microorganisms, reducing the quality of eggs. Furthermore, fermentation of juices is known to decrease oviposition efficiency, and daily sanitation of oviposition devices is required. Here, in a laboratory-scale study, we evaluate the effectiveness of four synthetic oviposition stimulants (OS) of B. dorsalis for egg production in dual choice tests, using oviposition devices similar to those used in mass rearing. Results indicated that gamma-octalactone, benzothiazole, octen-3-ol and ethyl tiglate significantly increased egg laying compared to controls (water). Of these, gamma-octalactone was particularly effective and elicited a 263-fold increase in oviposition on treated oviposition devices compared to control. Our findings demonstrate the potential of using OSs to improve the efficiency and cost effectiveness of mass production of B. dorsalis.