The Status of Bactrocera dorsalis as an Emerging Predominant Pest in the Commercial Fruit Industry in Sri Lanka

Fruit flies (Diptera: Tephritidae) are considered as the most virulent insect pest group in the fruit industry worldwide. However, there are no sufficient previous studies and information on their severity and dominance levels in the fruit industry of Sri Lanka. Hence, the present study aimed to access their abundance and dominance level and, based on the present findings, the potential risk of B. dorsalis is presented herein further. The study was carried out using randomly selected eight (08) fruit stalls as two stalls from each bio-climatic zone. Adult fruit flies were collected using methyl-eugenol field traps from fruit stalls. Trapped flies were identified using standard taxonomic keys. Simpson Population Dominance Index and the Abundance Index for recorded fruit flies were calculated. Four Bactrocera fruit flies; B. dorsalis, B. kandiansis, B. correcta and B. latifrons were recorded. Among them, Bactrocera dorsalis showed the highest percentage abundance in all selected fruit stalls and also in all bio-climatic zones (P<0.05). Out of the four species, B. dorsalis recorded the highest dominance index value (0.61) showing as they are `High` dominance level pest. As such, B. dorsalis has an emerging pest risk as the predominant fruit fly species in the fruit industry in Sri Lanka. Study findings will be helpful for fruit sellers, cultivators and agriculture authorities in implementing control measures to secure the commercial fruit industry in Sri Lanka.