Leslie model for predatory gall-midge population

A Leslie matrix model for predatory gall-midge is constructed. From the mod el we estimate the stable age distribution which is important when the gall -midge is used in biological control. We compare the two common parametriza tions of Leslie matrix., i.e. the flow-birth and the pulse-birth projection s. We show that both parametrizations lead for the given data set to practi cally the same results. Then we study the optimal gall-midge introduction s cheme which leads quicker to the stable age distribution if only certain in stars can effectively be introduced. This is also important, because in bio logical control we need to minimize the time that a population needs to rea ch the stable age distribution. (C) 2000 Elsevier Science B.V. All rights r eserved.