Agriculture is one of the top ten revenue-producing industries in North Carolina accounting for 22 percent of the state's income and employing over 18 percent of the workforce.  Disease prevention is an integral part of crop management.  Appropriately timed chemical applications can mitigate yield losses by preventing disease onset, but should only be used when environmental conditions favor disease development.  Over-application can exacerbate non-target problems.

North Carolina ranks fourth in the nation for peanut production. Several plant diseases can adversely affect peanut crops.  Two major diseases that concern growers include peanut leaf spot and Sclerotinia blight.  If uncontrolled, peanut leaf spot can cause yield loss of 50 percent or more in one season. Sclerotinia blight can spread rapidly under a peanut canopy and result in yield loss of up to 80 percent in severe cases.   

The goal of this project is to identify periods of time when fungicide protection is needed based on recent weather conditions, which are collected by the NC ECONet stations (a mesonet maintained by the SCO) and are available through the NC CRONOS Database of the State Climate Office of North Carolina.

A method has been developed to automatically produce leaf spot and Sclerotinia disease advisories each morning.  The advisories are based on simple published algorithms that compute the number of favorable hours for disease development.  The algorithms consider specific environmental conditions such as air temperature, soil temperature, daily precipitation and relative humidity.  Based on predetermined thresholds of these parameters, the daily count of favorable hours is incremented.  Once a sufficient number of favorable hours have accumulated, conditions for disease development exist and an affirmative spray advisory is generated.  If conditions do not yet exist for disease development, the advisory contains pertinent details for the grower.

Each morning, the advisories are forwarded to County Extension Agents for dissemination to growers. This information helps growers improve crop management through more time-accurate fungicide applications. Consequently, this will reduce costs, maintain or increase yields, and significantly decrease non-target effects.