A computer model was developed to simulate and predict the phenology of Mexican bean beetle (MBB), Epilachna varivestis Mulsant, populations on dry beans, Phaseolus vulgaris. Time-varying distributed developmental rates of the egg, four larval instars, and pupal stages were simulated with degree day models, based on a standardized cumulative probability distribution function from a range of constant temperature experiments. Predictions from the simulation model provided a good fit to the observed constant temperature data and field experiments. Using temperature data in the form of daily maximums and minimums, the model can be used to predict the occurrence of immature MBB stages under field conditions, when the frequency distribution of egg mass recruitment is known.

Recent trends in agriculture towards reduced pesticide use and ecological sustainability have lead to increased interest in spiders as potential biological control agents. Although the Chinese have augmented spider populations in field crops as a pest management strategy for centuries, much debate remains as to whether spiders will effectively control pest populations in U.S. agricultural ecosystems. This technical bulletin reviews the literature to describe the reduction of insect pest densities by spiders and the effects of pesticides on spiders. In addition to addressing the question of whether spiders can be effective biocontrol agents, the authors outline techniques to conserve and enhance spider assemblages.