Population dynamics of vegetable flies during winter on Reunion Island

Abstract

On Reunion Island, three species of flies, Bactrocera cucurbitae, Dacus ciliatus and Dacus demmerezi (Diptera-Tephritidae), cause severe damage to Cucurbit crops. To implement effective crop protection programs, it is important to know how they overwinter in order to improve the control of the fly populations at the beginning of infestation. The aim of our study was to obtain knowledge on the population dynamics of these three fly species during the winter. Three technics were tested on five sites: adult trapping, collecting damaged fruit placed for emergence in the laboratory, and counting pupae in soil samples. Our results show a variation of the population level during the year and especially a decline during winter. They also show a distribution of the species according to altitude. The flies probably spend the winter season in quiescence.