Net choice is key to the augmentorium technique of fruit fly sequestration and parasitoid release

Abstract

In Reunion Island, tephritid fruit flies are the main pests of fruit and vegetable crops, causing severe yield losses. Instead of the curative approach to reducing populations, this study focused on a particular sanitation technique, which forms the basis of Integrated Pest Management (IPM) in this context, using a tent-like structure called an “augmentorium” the aim of which is to contribute to controlling these pests. This structure sequesters adult flies emerging from infested fruit while allowing the parasitoids to escape, via a net placed at the top of the structure. The size of four nets was tested in the laboratory in order to include the most effective one in an augmentorium prototype adapted to the conditions of Reunion Island. The mesh finally selected (hole area 3.00 mm 2) proved to be perfectly effective with 100% sequestration of adult flies ( Ceratitis capitata, Bactrocera cucurbitae, Bactrocera zonata). In addition, 100% of the parasitoids ( Fopius arisanus and Psyttalia fletcheri) were able to escape from the cage through the mesh if they chose to do so. Farmers were enthusiastic about using the augmentorium prototype. Implications for the use of this technique in Reunion Island are discussed.