A troubleshooting guide for mechanistic plant pest forecast models

There is copious literature on development and validation of models to forecast risk to crops from arthropods and diseases; however, there is little published on causes of failure associated with these models. This manuscript provides mechanistic model builders and users with a list of likely problems, potential causes, possible solutions, and associated references. The problems are divided into four categories: environmental inputs, model construction and parameterization, validation, and implementation. The list is based on the authors' extensive experiences developing and running mechanistic modeling systems. A multidisciplinary approach involving researchers with expertise in pest biology, crop management, meteorology, and information technology is recommended for delivering the most effective pest forecast models.