Institution:North Carolina State University
Project Fiscal Year:2013
Report Received Date:
Project NPB Budget:$10,000
Sclerotinia blight is one of the three most important peanut diseases in North Carolina. The primary product for Sclerotinia blight control (Omega) is very expensive, costing between about $50 and $75 per spray, depending on the application rate. In previous tests, the group 7 fungicide Fontelis applied at 1.5 pints per acre reduced the incidence of Sclerotinia blight by about one-third. The level of control attained often was statistically equal to control from Omega at 1 pint per acre. Fontelis is primarily used to control stem rot and leaf spot. For these diseases, a rate of 1 pint per acre is recommended. No suppression of Sclerotinia blight was observed with Fontelis at the 1 pint per acre rate in previous trials.
In many seasons, the final leaf spot spray in early September coincides with a period of rapid Sclerotinia blight development. This presents a trade-off between the need for resistance management with Bravo sprays and Sclerotinia blight control since Bravo can make Sclerotinia blight worse. Using Fontelis as the final leaf spot spray could control leaf spots and control or suppress Sclerotinia blight.
Another means of reducing the cost of Sclerotinia control is to identify problem fields so that they could be avoided. A soil assay for the Sclerotinia fungus could identify risky fields, but the currently available methods are much too time consuming to be used for grower recommendations. New advances in molecular methods for identifying and quantifying pathogens from soil (real-time PCR) may make routine assays for Sclerotinia possible. However, we first need to have a better understanding of the relationships between the amount of the pathogen in soil and the amount of disease that develops. This will help us to set detection thresholds and determine the level of precision needed from a new assay.