Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2008
Publication Date: 7/26/2008
Citation: Obuya, J.O., Hanson, L.E., Stump, W.L., Franc, G.D. 2008. A rapid diagnostic tool for detecting benzimidazole resistance in Cercospora beticola, the causal agent of Cercospora leaf spot in sugarbeet [abstract]. American Phytopathological Society Annual Meeting. 98:S115. Interpretive Summary:
Technical Abstract: Resistance in Cercospora beticola to benzimidazole fungicides was selected in many sugar beet regions of the world due to extensive use of this fungicide class. Practical resistance to benzimidazole in populations of C. beticola was first reported in Greece in 1973. Resistance has subsequently been found in the majority of the growing areas worldwide, including C. beticola populations resistant to benzimidazole in the upper Midwest and in the High Plains region of the United States. Although benzimidazole use was reduced, it sometimes is still used in combination with other fungicide classes for C. beticola suppression. Rapid diagnostic methods are needed for detecting benzimidazole resistance in field isolates, with the goal of quickly providing information to producers pertaining to fungicide selection and disease management. Current methods require several weeks, which is too long to be used in making management decisions. Resistance to benzimidazoles can be due to several potential single nucleotide polymorphisms in the ß-tubulin gene. Based on characteristics of the predominant mutation detected in the High Plains pathogen populations, a diagnostic tool was developed that utilizes a combination of polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). The same mutation has been detected in isolates from other U.S. growing regions. Thus this method may be useful in many production areas. This diagnostic tool enables rapid discrimination between benzimidazole resistant and benzimidazole sensitive isolates of C. beticola.