GPA-Phenodynamics, a simulation model for the population dynamics and phenology of green peach aphid in potato: formulation, validation, and analysis

A model, GPA-Phenodynamics, was developed for the population dynamics and phenology of green peach aphid, Myzus persicae (Sulzer), in potato during the summer: the model describes the interaction among the green peach aphid population, its predators, and abiotic factors (e.g. temperature). The model includes functions for population growth of the aphid and its predator complex. Developmental degree days were used for the time dimension. Model agreement with field data was good. The model precisely predicted (within 2 days) when the aphid reached its highest density. A regression analysis between observed and predicted population density showed a slope of 0.952 with a coefficient of determination equal to 0.976. Model output was sensitive to the intrinsic rates of increase for green peach aphid and its predator complex. Degree days required for the aphid and its predator complex to appear in potato were described as uniform random distributions with different means and deviations. Using 10 different sets of generated weather data, the model successfully simulated phenologies and dynamics of the aphid population. GPA-Phenodynamics can be used as a decision-making tool in integrated pest management program for green peach aphid in potato fields during the summer season.