Resistance of plant pathogens to fungicides in New Zealand

Abstract

Before 1970, only one example of acquired resistance to fungicides in pathogen populations was recorded in New Zealand. This was resistance in Pyrenophora avenae to mercury-based fungicides. Since 1970, acquired resistance to fungicides in pathogens has become a major problem in disease control. Several pathogens have acquired resistance to benzimidazoles; Botrytis cinerea and Monilinia fructicola to dicarboximides; Phytophthora infestans to acylalanines; Penicillium italicum to guazatine; and Pyrenophora teres to triazoles. Observations on the ability of resistant strains to persist in the absence of selection and suggested strategies for prolonging the effective life of the fungicides are reviewed.

Keywords:

• plant pathogens
• fungicide resistance
• control
• population dynamics
• mercury-based fungicides
• benzimidazoles
• dicarboximides
• acylalanines
• guazatine
• triazoles