Assessment of Simultaneous Application of SIT and MAT to Enhance Bactrocera Fruit Fly Management

The Sterile Insect Technique (SIT), which is likewise an environment friendly technique involves the mass-rearing of male insects, sterilizing them by ionizing radiation and releasing them in the target area in numbers large enough to outcompete their wild counterparts. Sterile male insects mating with wild female insects will have result in no off-spring and the release of sterile males in adequate sterile to wild male over-flooding ratios suppresses the wild population in the targeted area. In certain cases, this population suppression can lead to eventual eradication of the target population. Furthermore, as the SIT acts in an inverse density dependent manner, it becomes therefore more effective when the wild population is reduced. The male annihilation technique (MAT) has been used to suppress Bactrocera pest species as part of an integrated pest management approaches, and even successfully applied to eradicate populations in some isolated situations such as of islands or outbreaks.  Integration of the male annihilation technique (MAT) with the SIT has so far been sequential, rather than simultaneous, with the SIT applied after a significant reduction of the wild population with the MAT; the reason being to avoid the mass-trapping of the released sterile males in the lured traps with the semichemical Methyl Eugeno; which would significantly reduce the efficacy of the SITThe development of cost-effective semiochemical treatments and delivering systems that improve sterile male sexual performance and reduce their response to male annihilation technique (MAT) formulations is highly desirable so that MAT and Sterile Insect Technique could be integrated. Even though the incorporation of semiochemical supplements for Bactrocera species appears feasible, practical and standard procedures to implement them at an operational scale still need to be developed and validated. Thus, exploring the potential of such an approach is essential in view that the simultaneous MAT and SIT application has considerable potential to drastically increase sterile to wild male overflooding ratios and therefore SIT cost-effectiveness. The combination of male replacement plus male enhanced performance increases what can be achieved with the same number of sterile flies: treating a wider area or enabling more rapid suppression or eradication. Furthermore, due to the increased cost-effectiveness, decisions to invest in SIT may be facilitated in situations where this would not otherwise be feasible. The CRP objective is to explore the potentially synergistic relationship between MAT and SIT when applied simultaneously to dramatically improve the efficacy of Bactrocera fruit fly management. The assessment of semiochemicals to enhance Bactrocera spp. SIT application against these pest fruit flies will include:Assessment of the effect of exposure of major Bactrocera pest species to semiochemicals on earlier sexual maturation and improved male sexual performance, as well as reduced response of exposed sterile males to MAT traps. Evaluation of key parameters in large field cages such as wild fly sex ratio, degree of lure response of sterile flies, sterile:wild over-flooding ratio and bisexual release to determine their influence on the effectiveness of simultaneous MAT and SIT.Field evaluation of simultaneous MAT and SIT within a pilot or operational setting that includes compatible management practices.