AU-Pnuts Advisory I: Development of a Rule-Based System for Scheduling Peanut Leaf Spot Fungicide Applications. J. C. Jacobi, Senior Research Associate; Department of Plant Pathology, Auburn University, Ala. 36849 . P. A. Backman, Professor, D. P. Davis, Former Postdoctoral Fellow, and P. M. Brannen, Research Assistant, Department of Plant Pathology, Auburn University, Ala. 36849. Plant Dis. 79:666-671. Accepted for publication 17 March 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0666.

The AU-Pnuts advisory was developed to schedule both the initial, and subsequent fungicide applications for control of early (Cercospora arachidicola) and late (Cercosporidium per-sonatum) leaf spots of peanut. The advisory uses the number of days with precipitation greater than 2.5 mm and National Weather Service precipitation probabilities to predict periods favorable for development of early and late leaf spot. Field experiments were conducted from 1989 through 1992 to assess the impact of the AU-Pnuts advisory on early and late leaf spot incidence and yield of Florunner peanut. Use of the AU-Pnuts advisory resulted in a 4-year average of 1.25 fewer fungicide applications than the conventional 14-day schedule. Leaf spot disease control and yields were equivalent to or better than the 14-day schedule. The AU-Pnuts advi-sory can be used to reduce the number of leaf spot fungicide applications and achieve disease control and yield similar to that with peanuts sprayed on the 14-day schedule.