Changes in the Efficacy of Pyraclostrobin for Control of Peanut Leaf Spot Diseases

摘要

In the southeastern United States, control of early leaf spot (Cercospora arachidicola) and late leaf spot (Cercosporidium personatum) of peanut (Arachis hypogaea) is heavily dependent on the use of fungicides. Pyraclostrobin is a strobilurin (group 11) fungicide that was labeled for use on peanut in the U.S. in 2002. Results from trials conducted in 1999 and 2000 indicated that treatments of 112 g a.i./ha or higher of pyraclostrobin applied 5 times at 21-day intervals were superior to 1.26 kg a.i./ha of chlorothalonil applied 7 times at 14-day intervals. In recent years, however, levels of leaf spot control achieved with treatments that included pyraclostrobin have not been consistent. In many cases, treatments included other fungicides, so which fungicide was responsible for control or lack thereof was not always discernable. The objective of this study was to compare full season applications of pyraclostrobin to chlorothalonil and other fungicides for leaf spot control.