title: Optimal timing of multiple applications of pesticides with residual toxicity.
abstract: Optimal timing of pesticide applications depends upon many factors including pest population demography, crop susceptibility to damage, weather and the rate at which a pesticide loses its toxicity. An efficient numerical optimization procedure incorporating these factors is developed and applied to the control of the Egyptian alfalfa weevil [Hypera Brunneipennis (Boheman)]. The procedure differs from earlier approaches in that the state vector describes the schedule of previous pesticide applications. Population density and age structure are used indirectly in construction of an equation which estimates pest damage to the crop as a function of the state vector. This approach can be used to calculate optimal timing of multiple pesticide applications based on a more detailed population model than previously has been possible. Calculation of the optimal pesticide application schedule with 11 age classes and 28 decision periods required only 25 seconds of CPU time on an IBM 370/168 computer.
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000378:metabolism; D003201:Computers; D005260:Female; D010058:Oviposition / Q000187:drug effects; D010573:Pesticide Residues; D010575:Pesticides / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D010573:Pesticide Residues; D010575:Pesticides