Lack of cross‐resistance to a novel succinate dehydrogenase inhibitor, fluopyram, in highly boscalid‐resistant isolates of Corynespora cassiicola and Podosphaera xanthii

• DOI: 10.1002/ps.2092
• Publication Date: 2011-01-11T21:04:19Z
• Authors: Hideo Ishii; Takuya Miyamoto; Shingo Ushio; Makoto Kakishima
• Keywords: Corynespora cassiicola

Recently in Japan, isolates resistant to boscalid, a succinate dehydrogenase inhibitor (SDHI), have been detected Corynespora cassiicola (Burk. & Curt.) Wei and Podosphaera xanthii (Castaggne) Braun Shishkoff, the pathogens causing leaf spot powdery mildew disease on cucumber, respectively. Resistant of C. are widely distributed represent serious problem control at present. Novel SDHI fungicides, including fluopyram, now under development.The growth very highly boscalid-resistant, sensitive was strongly suppressed fluopyram-amended YBA agar medium. Although boscalid another SDHI, penthiopyrad, hardly controlled cucumber plants when or boscalid-resistant were employed for inoculation, fluopyram still exhibited excellent efficacy against these as well P. xanthii.Differential sensitivity penthiopyrad clearly found two important may indicate involvement slightly distinct site action from other SDHIs. This finding lead discovery unique SDHIs future.