Resistance Risk and Current Status


Benzimidazoles represent the beginning of serious resistance problems in fungicides. A few years after commercialisation, loss of disease control with benzimidazole fungicides was recorded in many crops, especially with pathogens having numerous cycles per year, such as Botrytis cinerea. For pathogens having only 1-2 cycles per year, resistance developed after a longer period of use, e.g., more than 10 years for cereal eyespot caused by Tapesia spp. Nevertheless, benzimidazoles are still used widely and continue to be valuable fungicides in global agricultural production.

Since commercialization resistance to benzimidazoles has been reported in approximately 60 genera in over 115 species of fungi. Table 1 gives an overview of published information relative to resistance development in pathogenic fungi affecting economically important crops globally.

Cases of resistance to benzimidazole on key pathogens in economically important crops.

Crop(s) Disease First report of field resistance
Cereals Powdery mildew
Fusarium spp.
Septoria spp.
1973
1976
1985
Vines Botrytis spp.
Powdery mildew
1971
1980
Pome/Stone Fruit Anthracnose
Powdery mildew
Monilinia spp.
Venturia spp.
Penicillium spp.
1994
1975
1973
1973
1974
Banana Mycosphaerella fijiensis 1982
Vegetables
Cucurbits - Solanacea
Botrytis spp.
Powdery mildew
Cladosporium spp.
Fusarium spp.
Verticillium spp.
Rhizoctonia spp.
1987
1970
1972
1973
1976
1986
Peanuts Cercospora arachidicola
Cercosporidium personatum
1974
1974
Oilseed rape and
other field crops
Sclerotinia sclerotiorum 1997

For a more detailed list of cases of resistance to benzimidazoles and other fungicides, see the List of Resistant Plant Pathogenic Organisms - February 2013.

Please send any additions or corrections about these tables to Jean-Luc Genet at Jean-Luc.Genet@dupont.com.

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