The COTton Farm-Level EXpert (COTFLEX) has been designed to integrate the best available information on production, marketing, and policy decisions relating to cotton production into a single decision aid package that will be deliverable to farmers, extension personnel, and financial institutions as end-users. A modular design of five principal advisors consisting of sets of component expert systems (CES's) allows COTFLEX to address broad problems of cotton production while keeping the scope of individual CES's tightly defined. The link between economic and production problems is described and an example from the system's Pest Management Advisor (PMA) is presented in which the system recommends actions for the control of cotton fleahopper in the Southern Blacklands of Texas. The PMA relies on simulation models and expert opinion for its advice.