OPTIMAL SEASONAL BIOCONTROL FOREICHHORNIA CRASSIPES

Abstract

This article studies the effect of reduction of an invasive species' competitive ability against another aggressive species, where the intra- and inter-species competition effect on the system is modeled as a control variable. Thus, following the example of competition between water hyacinth–water lettuce, where the competitive ability of the water hyacinth is reduced by the presence of the biological agent Neochetina eichhorniae (weevil) we apply optimal control to compare the effects of the weevil on the competitive relationship. With the effect of the reduced competitive ability been obvious during the larvae stages of the weevil. An objective functional is formulated to minimize the invasive species while minimizing the cost of implementing the control. Numerical results are examined for various parameter values.