Disease Note

Criconema mutabile Associated with Bacterial Canker and Nemaguard Rootstock. M. V. McKenry, Department of Nematology, University of California, Riverside 92521. M. Viveros, and B. Teviotdale. Cooperative Extension, Kern County Farm Advisor, 1031 S. Mt. Vernon Avenue, Bakersfield, CA 93307; and Department of Plant Pathology, University of California, Berkeley 94720. Plant Dis. 74:394. Accepted for publication 26 February 1990.DOI: 10.1094/PD-74-0394D.

Bacterial canker complex was diagnosed as the cause of tree and limb death in a declining apricot (Prunus armeniaca L.) orchard of mixed cultivars on Nemaguard rootstock located near Shafter, California. The 8-yr-old trees showed classical symptoms of springtime death: sour sap odor, gumming, and cankers. This is the first report of bacterial canker complex within Kern County. Diseased trees were restricted to a site of coarse sandy soil. Nematode extraction by sugar centrifugation of soil samples revealed a high (2,000/250 cm³ soil) and pure population of Criconema mutabile Taylor. The land had a long history of acala-type cotton (Gossypium hirsutum L.) cultivars. C. mutabile is noticeably shorter than Criconemella xenoplax (Raski) Luc & Raski and has a wider host range. The wider host range of C. mutabile is important when crop rotation or cover cropping programs are being considered for stone fruits. This is the first report of C. mutabile associated with bacterial canker complex.