OPTIMIZATION OF INSECTICIDE TREATMENTS IN RIVERS - AN APPLICATION OF GRAPH-THEORY FOR PLANNING A BLACK FLY LARVAE CONTROL PROGRAM

Combining a model of susceptibility of black fly larvae to commercial formulations of Bacillus thuringiensis var. israelensis and a one-dimensional transport equation in a river, the quantity of larvicide that should be applied at a given site in order to achieve a given mortality downstream can be calculated. The obtained relation, a function of biological and hydrological parameters, allowed the authors to calculate costs related to the treatment of a section of river. It is then possible to determine an optimal strategy of treament which minimizes the quantity of an insecticide applied and the logistic movement between injection sites. An experimental treatment conducted in the Onchocerciasis Control Program in West Africa is analyzed as an example. -from Authors