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Resistance

Effects of Growing Conditions on Wound Repair and Disease Resistance in Pachysandra terminalis. George W. Hudler, Department of Plant Pathology, Cornell University, Ithaca, NY 14853; Brenda G. Neal, and Mark T. Banik. Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 80:272-277. Accepted for publication 11 September 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-272.

Wounds on stems of Pachysandra terminalis differed in susceptibility to subsequent colonization by Volutella pachysandricola, depending on the time of year that the wounds were inflicted and the age of the wounds when inoculated. When plants growing out of doors were wounded and inoculated in April or May, some wounds up to 11 days old were susceptible. However, plants growing in the same stand and wounded later in the growing season (June, July, September) were significantly more resistant. All but one of 210 wounds more than 4 days old were immune. Wounds on manually defoliated plants were not significantly more susceptible than nondefoliated checks. However, plants exposed to deicing salt in soil and plants growing in full sun were significantly more susceptible to colonization by V. pachysandricola than their counterparts growing under more favorable conditions. Histological comparisons of wound repair processes of plants growing under various conditions suggested that prolonged susceptibility was not related to the rate of lignification of parenchyma subjacent to the wound surface but may have been related to deposition of intracellular suberin in those same cells.