Effect of Adjuvants on the Performance of Pyraclostrobin for

Abstract

Cercospora leaf spot (CLS), caused by the fungus Cercospora beticola, is the most damaging foliar disease of sugarbeet (Beta vulgaris L.) in Minnesota and North Dakota. Most fields require fungicide applications to control CLS and to improve sugar yield and quality. Trials were conducted near Breckenridge, Minnesota, in 2001 and 2002, to determine the effect of adjuvants added to pyraclostrobin on control of CLS and on sugarbeet yield and quality. Cercospora leaf spot severity was low in both years of the trial. Pyraclostrobin applied alone always provided effective control of Cercospora leaf spot. Adjuvants in combination with pyraclostrobin did not result in a significant improvement in disease control, yield, and quality compared to pyraclostrobin applied alone. Addition of adjuvants to pyraclostrobin in most cases increased phytotoxicity, and in some instances reduced yield, compared to pyraclostrobin applied alone. Based on these results, there was no consistent benefit of adding adjuvants to pyraclostrobin for CLS control or for increased sugar yield and quality.