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Infection of Pruning and Small Bark Wounds in Almond by Ceratocystis fimbriata. Beth L. Teviotdale, Extension Plant Pathologist, University of California, Berkeley, Kearney Agricultural Center, Parlier 93648. Dennis H. Harper, Staff Research Associate, University of California, Berkeley, Kearney Agricultural Center, Parlier 93648. Plant Dis. 75:1026-1030. Accepted for publication 8 April 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-1026.

Ceratocystis fimbriata caused cankers at pruning cuts on branches of Nonpareil almond trees inoculated in all months from September through February. Pruning cuts were susceptible when 014 days old, and canker length was greatest where fresh wounds were inoculated. Small dead or living twigs of Mission almond trees, broken without visible exposure of the subtending branch cambium, and wounds inflicted with a lancet became infected when inoculated in alternate months throughout the year. Superficial abrasions of the periderm were less susceptible than were full- and half-depth penetrations of the bark. There were no significant differences in percent infection among sites bearing two, four, six, and eight punctures. Wounds became less susceptible to infection with age, and mean canker lengths did not differ. Percent infection of open bark wounds, made by a cork borer, decreased with decreasing inoculum concentration (102106 endoconidia per milliliter) and increasing age (014 days).