A Cellular Automata Model

A cellular automata model for the transmission of Citrus Variegated Chlorosis (CVC), a disease that devastates citrus tree yields, has been developed by researchers at the Federal University of Vicosa and Instituto Agronomico de Campinas in Brazil. The model simulates the travels of sharpshooter leafhopper insects, the primary CVC transmission vector, between citrus groves.

The researchers (M.L. Martins, 011-55-031-899-2993, mmartins@mail.ufv.br) assumed that the insects infect a number of plants in one area, and occasionally travel long distances to feed on, and ultimately infect, plants in another area. Models of random motion that include such leaps from one area to another, known to mathematicians as Levy flights, are often applied in studying the physics of chaotic systems involving fluid flow, chemical kinetics, and semiconductors.

In addition to the new CVC transmission insights, Levy flights have recently proven valuable in understanding the foraging activity of animals from amoebas to deer, and for simulating human activities such as the childhood game of hide-and-seek. Plant stress and seasonal effects were among the factors that influenced the Lévy flights in the model which predicts CVC epidemic progression much more accurately than models relying on less sophisticated, random-walk simulations of insect behavior. (Martins et al., Physical Review E, November 2000; Select Article.)