Host Plants Serving as Refuges for Fruit Fly Populations during Mango Off-Season in Southern Côte d’Ivoire

This study was conducted from October to December 2017 in the CNRA fruit orchards in Azaguié (southern Côte d’Ivoire) in order to identify alternative host plants and refuge areas for mango fruit flies during mango off-season. Six attractants were spread in a 3 to 4 ha orchard, resulting in the capture of 6 440 flies, mainly Bactrocera dorsalis. Methyl eugenol and Torula were the most effective attractants, recording 4 380 flies (average: 243.3 flies/trap/week) and 1 484 flies (247.3 flies/trap/week), respectively, of which more than 97% were B. dorsalis. Residual fruits from 19 fruit tree species were collected and incubated. Emergence was observed on only four species: Pouteria campechiana (Sapotaceae), Myrianthus arboreus (Cecropiaceae), Chrysophyllum cainito (Sapotaceae), and Annona esculenta (Annonaceae). Infestation levels varied: P. campechiana: 672 larvae, 545 pupae, pupation rate 85.7%; emerged species: C. punctata (81.5%) and B. dorsalis (18.5%); Myrianthus arboreus: 464 larvae, 423 pupae, pupation rate 91.5%; C. anonae domine (94.3%); a native parasitoid, Fopius caudatus, represented 5.7% emergence; C. cainito: 33 larvae, 15 pupae, pupation rate 45.5%, emergence 53.3%, exclusively B. dorsalis; A. esculenta: 503 larvae, 255 pupae, pupation 71.9%, emergence 48.9%, only B. dorsalis. A total of four fly species were identified (B. dorsalis, C. cosyra, C. punctata, C. anonae) as well as a parasitoid, Fopius caudatus (Figure 1). The results showed that the orchards of Azaguié constitute an active refuge area for Tephritidae during the inter-seasonal period, promoting the survival of B. dorsalis and the presence of secondary host plants, and revealing a potential for natural biological control that remains under-exploited.

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