Variation of <i>Bactrocera dorsalis</i> Hendel (Diptera: Tephritidae) fruit damage and population dynamics with mango phenology in bioclimatic zones of Sri Lanka

Abstract Aims : Bactrocera dorsalis (Hendel) has been identified as a significant fruit pest in Asia, particularly Sri Lanka. Nonetheless, research on fruit fly population ecology and host phenology is scarce in Sri Lanka. Thus, the purpose of this study was to examine B. dorsalis fruit damage and population variation in relation to the fruiting phenology of selected commercial mango varieties in Sri Lanka. Methods : The study was carried out from January 2021 to January 2023 using eight main sampling sites (two sites per bioclimatic zone) and two commercial mango varieties [Karutha kolumban (Kc) and Willard (Wld)]. Once per month, flies were collected using standard methyl-eugenol field traps, and mature, ripe mangoes were also collected from study sites. Fruit damage levels and fruit fly emergence were studied in the laboratory. Main findings : The patterns of fruit damage and population dynamics variation of B. dorsalis are in accordance with the fruiting season of mangoes in each bioclimatic zone. Kc reported the highest field abundance, fruit infestation, pupae, and adult emergence compared to Wld. The intermediate zone recorded the highest increase in B. dorsalis ’s field abundance, fruit damage, and population dynamics for both Kc and Wld (in 2021 and 2022). Conclusions : The main mango harvesting seasons in every bioclimatic zone have a significant impact on variations in mango damage and the population dynamics of B. dorsalis . During the main mango harvesting season for both Kc and Wld, B. dorsalis shows the highest increase of their population and fruit damage in the intermediate zone, while the lowest values reported in the wet zone. Study findings are vital to implementing fruiting phonology-based management practices to control fruit fly damage and population.