A multi-species, phenology (or timing) modeling system described under the acronym of PETE (Predictive Extension Timing Estimator) has been developed for use by extension personnel to schedule integrated pest management (IPM) activities for a tree-fruit pest complex and selected vegetable pests in the state of Michigan. This computer-based system contains a library of pest models in a generalized format with appropriate software programs for constructing models with limited computer programming. It allows automatic operation, spot checking of pest status in the field, model testing, and model validation. When used with an earlier developed Pest Management Executive system (PMEX), it enables IPM extension personnel to monitor key events in the field and make appropriate recommendations to growers. The value of this program for summarizing phenological research and its practical value for implementing IPM methods are discussed.