Assessment of infection and sporulation processes of Puccinia menthae on peppermint in controlled conditions

Abstract

The effects of environmental factors on components of the life cycle of Puccinia menthae on Mentha × piperita cv. Tod’s Mitcham were examined. Urediniospore germination required at least 6 h leaf wetness and lasted 4-6 h at temperatures of 5-25ºC. Appressoria, substomatal vesicles, and haustoria were produced 6, 6, and 24 h after inoculation, respectively, at 20ºC. The latent period of infection ranged from 50 days at 5ºC to 10 days at 22ºC. Sporulation occurred over a wide range of temperatures (5-27ºC), the optimum being 15-20ºC. The minimum, optimum, and maximum temperatures for infection were <5, 20, and 27ºC, respectively. Teliospore formation required a minimum of 9 days of cold treatment (4ºC) and the ratio of teliospores to urediniospores produced was inversely proportional to the duration and intensity of light received.