Nonlinearity and the effects of microclimatic variability on a codling moth population ( Cydia pomonella): A sensitivity simulation

Using a recently developed simulation model, we have examined the sensitivity of the dynamics of a population of codling moth to temperature variations of the magnitude that might reasonably occur between weather station measurements and tree canopy temperatures. Base temperatures used were from NOAA Weather Service records for 1976 and for 1978. Effects of temperature variation showed different patterns for the 2 years. Examination of the temperature dependence of rates of development and of mortality for the developmental life stages, indicates that the difference arises from the nonlinear temperature dependence of the underlying life stage processes. Implications are discussed concerning both the qualitative nature of effects of temperature variations, and the nature of the experimental and monitoring data needed if simulation models are to be useable for predicting and controlling codling moth populations.