Description

Abstract: A disease-forecasting method for groundnut leaf spot diseases was developed in Georgia in 1966. The system is based on the effects of daily minimum air temperature and duration of relative

humidity equal to or greater than 95% on development of leaf spot epidemics. The system was computerized and daily spray advisories were issued to groundnut growers in the southeastern United States beginning in 1971. However, because of the availability of inexpensive fungicides that provided satisfactory control of leaf spots when applied at intervals of 14 days, the system was not widely accepted by growers in the United States. Currently there is a renewed interest in the system because of increased costs of fungicides, application costs, and the deleterious nontarget effects of some fungicides. In Virginia field trials from 1979 to 1982, the total number of

fungicide applications based on the leaf spot advisory program averaged 4.25 fewer applications per season than did the number of applications on a 14-day schedule.