VIEW ARTICLE

Resistance

Temporal Changes in the Infection Court After Wounding of Peach Bark and Their Association with Cultivar Variation in Infection by Leucostoma persoonii. A. R. Biggs, Research scientist, Agriculture Canada, Research Station, Vineland Station, Ontario, Canada L0R 2E0; Phytopathology 79:627-630. Accepted for publication 17 January 1989. Copyright 1989 Department of Agriculture. Government of Canada. DOI: 10.1094/Phyto-79-627.

Peach bark wounds 0, 7, 9, 11, 13, and 15 days old were inoculated with mycelium of Leucostoma persoonii, and colonization frequency and extent were determined. Six peach cultivars ranging in their relative susceptibility to L. persoonii were studied to test for the presence and extent of cultivar variation in wound response and the association of variation in wound response with susceptibility to fungal infection. Uninoculated wounds of similar ages and in close proximity to inoculated wounds also were sampled and examined histologically for morphological and histochemical changes associated with nonspecific plant defense reactions, especially the formation of suberized wound periderm. Peach cultivars varied in the rates at which they accumulated suberin, and suberin accumulation rate was correlated with the relative susceptibility of peach cultivars to infection by L. persoonii. By calculating the number of days to maximum resistance for each cultivar, that is, the point when the infection court was no longer susceptible to infection, it was estimated that the infection court of the most susceptible cultivar would remain receptive to inoculum approximately 19 days longer than the infection court of the most resistant cultivar used in this study.