A Safe Haven or a Temporary Alternative Host? - The Displaced Mango Fruit Fly, Ceratitis cosyra in the African Peach Plant

Abstract

One of the difficulties in controlling fruit flies in cultivated crops is the use of alternative host plants as refugia when the preferred hosts are not in season. This  study was aimed at collecting fruits and vegetables in localities across the five northern regions of Ghana (Northern, North-East, Savannah, Upper-East, and Upper-West regions) to catalogue the diversity of fruit flies and their host plants. A total of 1,722 fruits from all localities across the five regions were incubated, with 29.13% turning out to be fly-positive, yielding 1,141 individuals in four genera (Bactrocera, Ceratitis, Dacus, and Zeugodacus) and four species (Bactrocera dorsalis (Hendel), Ceratitis cosyra (Walker), Dacus bivittatus (Bigot), and Zeugodacus cucurbitae (Coquillet)). The African Peach plant, Nauclea latifolia, showed the highest incidence level of infestation, with the Mango fruit fly, Ceratitis cosyra as the dominant species, accounting for 97.19% (974) of the flies. The Oriental fruit fly, Bactrocera dorsalis and the Melon fly, Zeugodacus curcurbitae accounted for 1.23% (14 each), and Dacus bivittatus 0.35% (4). With evidence of displacement of C. cosyra from mango by the invasive Bactrocera dorsalis in most African countries, our results point to a plant that has hitherto not been known to be associated with fruit flies in Ghana for the displaced Mango fruit fly. Since information of previous fruit fly records is scanty, especially in the northern parts of the country, it is not known whether the African Peach has always been a host plant to C. cosyra, and served as a suitable alternative host during the long dry season, or is pointing to the new home after its displacement by Bactrocera dorsalis. There is therefore the need for an extended all-year-round collection to ascertain the host status and pattern of utilization of the African peach, as well as confirm the suspected host shift and displacement status of C. cosyra.