A Computer Simulation Model: The Velvetbean Caterpillar in the Soybean Agroecosystem

An example of a stochastic, computer-based model is described which displays the population dynamics and defoliation damage for velvetbean caterpillar, Anticarsia gemmatalis Hubner, infestation in soybeans. A factorial experiment with the model is described which investigated percent leaf damage at podset as a function of 4 variables and 2 levels of each variable. Worst case conditions for the experimental variables are identified as well as possible strategies for their avoidance. The experimental results led to development of probability calculations for the efficacy of sampling techniques in the field. The calculations implied that sample sizes should be increased by about an order of magnitude over present practice if small initial pest numbers are to be detected with high probability. General uses and values of systems simulation modeling are discussed.