The effects of phytosanitary hot water treatments on West African mangoes infested withBactrocera invadens(Diptera: Tephritidae)

Abstract

Introduction. Quarantine heat treatments have not yet been introduced in West Africa and no work has been done to determine the treatment conditions needed to eliminate eggs and larvae of West African fruit fly populations, especially of the new species Bactrocera invadens, from mangoes produced in the region. The objective of our study was to carry out hot water disinfestation experiments on naturally infested mangoes to determine the exposure parameters required to kill eggs and larvae of B. invadens present in commercial-quality fruits. The effects of hot water treatment on fruit quality were also investigated. Materials and methods. A tank with a heating element and a water pump equipped with a tank sensor were used. Physiologically mature, hard, green mango fruits (cv. Kent) with potential export quality but infested by B. invadens were harvested from plantations in the Bobo-Dioulasso (Burkina Faso) area. The effect of hot water treatment by immersion at 42.0 °C, 46.5 °C or 51.0 °C was evaluated by counting identifiable sites of fruit fly oviposition before and after paring the fruit and, finally, the numbers of live and dead larvae of B. invadens were counted in the pulp. The quality of the fruit was evaluated after the hot water immersion. Results and discussion. A hot water treatment resulting in a core temperature of 46.5 °C could be the basis of a fruit fly quarantine treatment for West African mangoes produced in Burkina Faso. All of the larvae extracted from the fruits treated at 46.5 °C and 51.0 °C were dead, while, in fruit treated at 42.0 °C, only about one-third of the larvae extracted were dead. (Resume d'auteur)