Socio-economic impact of biological control of mango mealybug in Benin

Mango mealybug, an exotic pest of mango, was first observed in Benin in 1986. In a biological control programme, natural enemies were successfully released in the following years. The present study is the first attempt to measure the impact of the biological control of mango mealybug over a large area, through a survey of mango producers. Most producers attributed the observed improvement of mango production to the success of biological control. Based on production estimates by producers, the negative impact of the pest on plant production and the positive impact of the introduced natural enemy were demonstrated. Interviewed mango producers gained on average US$ 328 per year by the biological control programme. Extrapolated to all producers of Benin, a yearly gain of US$ 50 million in mango production can be estimated. The present value of accrued benefits is estimated at US$ 531 million over a period of 20 years. The total cost of the biological control of mango mealybug is estimated at US$ 3.66 million, which includes initial costs in other African countries and the introduction of the natural enemy from India, resulting in a benefit-cost ratio of 145:1 for benefits in Benin alone. (C) 2002 Elsevier Science B.V. All rights reserved.