Susceptibility of Honeylocust Cultivars to Thyronectria Canker

Abstract

Six cultivars of Gleditsia triacanthos were inoculated with the fungus Thyronectria austro-americana in May, July, September, and November. Branches were excised and examined in the laboratory the following spring. Small cankers and extended xylem discoloration were present, but wilting and dieback did not occur. The fungus persisted in the wood of every tree inoculated but caused cankers at only 20% of the inoculation sites. More cankers were present on trees inoculated in September and November than in May or July. Cankers were most frequent on 'Sunburst', less frequent on 'Moraine' and 'Skyline', and least frequent on 'Imperial', 'Holka', and 'Shademaster'.