Development of an attract-and-infect system to control Rhynchophorus ferrugineus with the entomopathogenic fungus Beauveria bassiana

Abstract

BACKGROUND: A new Beauveria bassiana-based attract and infec t device (AID) to control Rhynchophorus ferrugineus Olivier(Coleoptera: Curculionidae) was developed. The virulence and persistence of the fungal formulation u sed in the AID wereevaluated in the laboratory. Semi-field and field trials were carried out to validate the results and establish the potential ofthis device as a control tool.RESULTS: In laboratory conditions, a 50% lethal time (LT50) of 4.33 days was obtained when adults (7–10 days old) were exposedto the inoculation tunnel (IT) containing 1 × 1010conidia g–1in an oil-based fungal formulation. This formulation maintainedconidium viability at 50% for up to 2 months. Moreover, when adults were exposed to 2.5-month field-aged ITs, mortality stillreached 50% 40 days after exposure. In addition, no differences were observed between ITs aged in early spring and those agedin summer, suggesting that the fungal formulation is not strongly affected by environmental factors in Mediterranean basinconditions. Semi-field assays showed that the device allowed an easy transit of weevils through the IT, which were effectivelyattracted and infec ted. Using the AIDs in 4-ha plot field trials, a reduction of >50% in the percentage of infested sentinel palmswas obtained.CONCLUSION: Based on the results obtained in terms of the efficacy and persistence of this new AID in the field and its potentialin reducing R. ferrugineus populations and palm infestation, this device could become a key tool for the management of R.ferrugineus.