Phytophthora Root and Crown Rot of Junipers in California. E. D. Standish, Graduate Student, Department of Plant Pathology, University of California, Davis 95616. J. D. MacDonald, Assistant Professor, Department of Plant Pathology, University of California, Davis 95616, and W. A. Humphrey, Farm Advisor, Orange County, CA. Plant Dis. 66:925-928. Accepted for publication 5 February 1982. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-925.

Isolations showed that Phytophthora cinnamomi was a predominant cause of root and crown rot of container-grown junipers in California nurseries. In one landscape planting, P. cryptogea was isolated from severely diseased junipers. In greenhouse experiments with P. cinnamomi, Juniperus sabina ‘Tamariscifolia’ and J. chinensis ‘Gold Coast’ were the most susceptible of eight cultivars inoculated. P. cryptogea caused serious disease on almost all cultivars but only when junipers were periodically exposed to flooded soil conditions, demonstrating the need for careful irrigation.

Keyword(s):