Host status of Citrus hystrix, Citrus aurantifolia, Passiflora edulis and Litchi chinensis for Bactrocera dorsalis (Tephritidae, Diptera) on Réunion Island

Abstract

Introduction -Determining the host status of fruit species for a given fruit fly species is essential to decide on its risk for the international trade of fresh fruits. This study aims to determine if Bactrocera dorsalis, the Oriental fruit fly, can infest fruits of four commercial species grown for exportation: Citrus aurantifolia, Citrus hystrix, Passiflora edulis and Litchi chinensis in La Réunion. Materials and methods -Fruits of C. aurantifolia, C. hystrix, P. edulis and L. chinensis were collected in the field to determine their natural infestation rates (natural hosts) and laboratory experiments were carried out to study insects' ability to oviposit and develop in the fruits (conditional hosts). Results and discussion -The two tested Citrus species were neither natural nor conditional hosts for B. dorsalis. Passiflora edulis was a conditional host for B. dorsalis on Réunion Island, as we observed infestations only in experimental conditions. Infestations in experimental and natural conditions by B. dorsalis were observed for L. chinensis. Conclusion -Our findings provided background information on the host status for B. dorsalis for four major fruits candidates for exportation from La Réunion. The risk for export is weak for tested Citrus species because they were neither natural nor conditional hosts for B. dorsalis. On the contrary, the risk for export is not null for L. chinensis and P. edulis, which present infestation by B. dorsalis either in field-collected fruit or in unperforated fruit in the laboratory. As infestations can be difficult to distinguish, post-harvest treatments should be considered to limit the risks.

Tri‐trophic interactions among Fopius arisanus, Tephritid species and host plants suggest apparent competition

“…We chose host plant species according to the infestation rates observed in the field in La Réunion for the target tephritid species (Moquet et al, 2021). We selected: (i) two host plants regularly visited by the three fruit flies studied: guava ( Psidium guajava L.), mango ( Mangifera indica L.); (ii) one host plant was only visited by B. dorsalis in La Réunion: papaya ( Carica papaya L.); and (iii) one host plant was never visited by fruit flies: lime fruit ( Citrus aurantifolia L., Moquet & Delatte, 2021). We used ripe fruit with no pesticide treatment.…”