Disease Note.

The Columbia Root-Knot Nematode, Meloidogyne chitwoodi, Discovered in the State of Utah. G. D. Griffin, USDA-ARS, Forage and Range Research Laboratory, Utah State University, Logan 84322. S. V. Thomson, Department of Biology, Utah State University, Logan 84322. Plant Dis. 72:363. Accepted for publication 11 December 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0363A.

The Columbia root-knot nematode (Meloidogyne chitwoodi Golden et al) is an important pathogen of potato and may cause economic losses unless adequately controlled. In the spring of 1983, a population (P3) of M. chitwoodi was found in Iron County, Utah. P3 is more virulent on potato than two populations (P I and P2) from Idaho. Greenhouse tests at 24 C resulted in 24, 32, and 64% infected and galled tubers from PI, P2, and P3, respectively. Because of the shorter growing season and cooler weather conditions in Utah, P3 causes minor galling of potato tubers. P3 is capable of parasitizing and reproducing on alfalfa; population ratios (final population/initial population) on Ranger, Lahontan, and Nevada Synthetic XX at 22± 4 C were 7.4, 5.8, and 2.7, respectively. This is the first report of M. chitwoodi in Utah and the second report of a population reproducing on alfalfa.