Developing a Fungal Based Trapping Station for the Control of Fruit Flies (Diptera: Tephritidae) in Hawaii

Abstract

Fruit flies (Diptera: Tephritidae) are a cosmopolitan species with many members of this family known to be economically significant pests. Research to understand the lifecycles and unique behaviors of these flies have been important to exploit critical points of development to control their populations. Many management strategies have been proposed, studied, and implemented across the world and have been met with success. But, with the ability of these flies to disperse, not all methods are applicable or successful in all regions. Entomopathogenic fungi are being studied in conjunction with the Tephritidae to determine efficacy against all life stages. Entomopathogenic fungi are capable of inducing high rates of mortality in adult fruit flies. The limiting factor of entomopathogenic fungi is its susceptibility to UV radiation. For this reason, it is widely used as a soil drench. Development of a product that incorporates entomopathogenic fungi to target adult fruit flies would be far more efficacious, adding one more tool to a widening array of management tools. Multiple stages of testing and development were performed, starting with determining the efficacy of Beauveria bassiana against three invasive tephritid fruit flies in Hawaii: Bactrocera dorsalis, Ceratitis capitata, and Zeugodacus cucurbitae. After confirming that B. bassiana kills adult fruit flies, we determined the lethal concentrations and developed a formulation that would be effective in a passive bait station, which included incorporation of lures and thickening agents.The effectiveness of each addition or modification to the formulation was assessed by measuring the mortality of exposed flies and the numbers of spores they picked up. The developmental goal of creating a formulation that could be vectored and dispersed across a population via horizontal transmission was confirmed, at least in lab cage trials. This fungal formulation could potentially be used as a new IPM tool for the control of tephritid fruit flies in both conventional and organic cropping systems.