Persistance of benomyl-resistant strains of Monilinia fructicola
In Australia, the persistence of benomyl-restant strains of Monilinia fructicola (EPPO A1 pest) was investigated. Benomyl-resistant isolates of the fungus were obtained from an orchard where the resistant strains were detected in 1976 and only three benomyl applications took place until 1988. A programme of 6 benomyl sprays over one season (1988-1989) on peach and nectarine trees resulted in the build up of a fungicide-tolerant population of the pathogen.
The author concludes that, where benomyl-resistant strains of M. fructicola have been detected, it may never be possible to resume the effective use of benzimidazole fungicides.
Sources
Penrose, L.J. (1990) Prolonged field persistence of resistance to benomyl in Monilinia fructicola.
Crop Protection 9, 190-192.