CHAPTER 17 - PLANT VIRUS EPIDEMIOLOGY AND COMPUTER SIMULATION OF APHID POPULATIONS

Abstract

This chapter discusses plant virus epidemiology and computer stimulation of aphid populations. Epidemiology is defined as the study of populations of plants infected with populations of virus particles that are spread by populations of vectors. At any given time, the incidence of infection by a virus in a population of plants, results from the past incidence of the disease and the recent activities of the vectors and virus. There have been two distinct and regrettably isolated approaches to plant virus epidemiology. In the first approach, entomolgists and virologists have recorded the abundance of insect vectors and the incidence of virus infections as these vary during a crop season. The second, or analytical, method of epidemiology is to arrive mathematically at a generalized equation of the graph of disease incidence over time or to describe mathematically and by deduction the epidemiological events and mechanisms in a population. However, both the these approaches neglect critical aspects of virus ecology. Plant virus epidemiology can be investigated using simulation models. The quality of the predictions is entirely dependent upon the quality of the data from which the model is prepared and the validity of the assumptions on which it is based. In the pea aphid model, the population dynamics of the vector had been tested experimentally in the field. The epidemiology of plant virus diseases has to be multidisciplinary. It requires special knowledge of botany, virology, entomology usually agriculture, mathematics, computer science and statistics, not to mention epidemiology itself.