Semiochemical mediated enhancement of males to complement sterile insect technique in management of the tephritid pest Bactrocera tryoni (Froggatt)

Mohammed Abul Monjur Khan,Olivia L. Reynolds,Nicholas C. Manoukis,Geoff M. Gurr,Terry Osborne,Idris M. Barchia

doi:10.1038/s41598-017-13843-w

Abstract

Queensland fruit fly, Bactrocera tryoni (Froggatt), is the most significant pest of Australia’s $9 billion horticulture industry. The sterile insect technique (SIT) and cue-lure (a synthetic analogue of raspberry ketone (RK))-based male annihilation technique (MAT) are two of the most effective management tools against this pest. However, combining these two approaches is considered incompatible as MAT kills sterile and ‘wild’ males indiscriminately. In the present study we tested the effect of pre-release feeding of B. tryoni on RK on their post-release survival and response to MAT in field cages and in a commercial orchard. In both settings, survival was higher for RK supplemented adults compared to control (i.e. RK denied) adults. A lower number of RK supplemented sterile males were recaptured in MAT baited traps in both the field cages and orchard trials compared to RK denied sterile males. The advantage of this novel “male replacement” approach (relatively selective mortality of wild males at lure-baited traps while simultaneously releasing sterile males) is increasing the ratio of sterile to wild males in the field population, with potential for reducing the number of sterile males to be released.

Highlights

Fruit flies of economic importance belong to the family Tephritidae, which is among the largest families of Diptera, comprising approximately 4000 species[1]
Mortality of sterile male B. tryoni was reduced when they were fed on a diet of 1% or 2% raspberry ketone (RK) compared with the control (RK denied)
The mean survival of sterile male B. tryoni after 5 weeks was higher for 1% and 2% RK diet treatments than 0.5% or the control (p < 0.05; Fig. 1b)

Summary

Introduction

Fruit flies of economic importance belong to the family Tephritidae, which is among the largest families of Diptera, comprising approximately 4000 species[1]. The most important fruit fly pest species in Australia is the Queensland fruit fly, Bactrocera tryoni (Froggatt), which attacks almost all commercial fruits and many vegetables[3]. In SIT programs, tephritids, including B. tryoni, are typically released as immature adults, one to three days after eclosion[7,8,9]. MAT uses large numbers of ‘bait stations’, containing a male attractant and an insecticide, which can significantly reduce local male densities[11,13,14,15]. Modelling studies19of tephritids, other than B. tryoni, suggest that MAT and SIT are synergistic and are more effective in combination than when used alone or consecutively provided that traps preferentially capture wild rather than sterile males

Methods

Results

Discussion

Conclusion