Economic impact of a classical biological control program: application to Diachasmimorpha longicaudata against Batrocera dorsalis fruit fy in Kenya

Abstract

Classical biological control (CBC) has been exploited as a safer alternative for suppressing the oriental fruit fy, Bactrocera dorsalis, by importing, rearing, and releasing the larval parasitoid, Diachasmimorpha longicaudata. Although D. longicaudata has been released in Kenya through the Africa Fruit Fly Programme, the extent of its dispersal and subsequent economic benefts have not yet been established. This paper models the spatio-temporal dispersal of the parasitoid using the fuzzy cellular automata approaches and estimates the net beneft from each dollar invested in the CBC approach. We calculated the return on investment based on funding into the programme between 2006 and 2015 and the result of the dispersal range of the parasitoid predicted using an artifcial intelligence algorithm. The investment yielded a signifcant net present value of US$42.8 million over the 16 years. Besides, the cost–beneft ratio showed that for every US$1 invested, the return beneft was US$93, confrming the proftability of the CBC program. The economic gains are signifcant considering that there is no environmental contamination and possible adverse efects from the CBC intervention. The study fndings support investment in biological control strategies for the eco-friendly and area-wide management of B. dorsalis.