Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2001
Publication Date: 8/1/2001
Citation: Thomas, S.H., Sanderson, S.A., Handoo, Z.A. 2001. First report of columbia root-knot nematode (meloidogyne chitwoodi) in potato in new mexico. Plant Disease 85: 924. Interpretive Summary: Nematodes are microscopic worms that attack plant roots and cause ten billion dollars of crop loss in the U. S. each year. Root-knot nematodes are a very important group which feeds on roots of many kinds of economic and other plants worldwide. A major problem with determining the extent of crop loss due to plant-parasitic nematodes is that the nematodes present in many areas are unknown. This brief report describes the discovery of the Columbia root-knot nematode in New Mexico on potato plants. The report is the product of collaboration of ARS, New Mexico State University, and the New Mexico State Department of Agriculture. Following a report of detection of Columbia root-knot nematode in potatoes imported by Mexico from the USA in spring 2000, five fields in San Juan County, New Mexico were surveyed in August 2000. Tubers from the 2000 potato crop exhibited symptoms of Columbia root-knot nematode, including warty exteriors and discrete small brown lesions that were apparent to a depth of 1 cm below the tuber surface. The lesions were examined and nematodes within them were identified as the Columbia root- knot nematode by examining them microscopically. The results are significant because this is the first report of this nematode of quarantine interest in New Mexico. This report will serve as a useful guide to researchers in planning future research, revising quarantine strategies, and identifying economically important species.
Technical Abstract: Following a report of detection of Columbia root-knot nematode in potatoes (Solanum tuberosum L.) imported by Mexico from the USA in spring 2000, five fields in San Juan County, New Mexico were surveyed in August 2000. Soil samples from two fields contained low to moderate numbers of second stage juveniles that were tentatively identified as Columbia root- knot nematode. Subsequently, state inspectors detected tubers from the 2000 potato crop that exhibited symptoms of Columbia root-knot nematode, including warty exteriors and discrete small brown lesions that were apparent to a depth of 1 cm below the tuber surface. Meloidogyne chitwoodi was confirmed from a sub-sample of infested tubers that was sent to the USDA Nematology Laboratory in Beltsville, MD in October 2000. Identification was based on morphological examination of the nematodes recovered from tubers. This is the first report of M. chitwoodi from New Mexico. In 1988 and 1989 no Columbia root-knot nematodes were recovered from soil samples collected at 26 locations throughout San Juan County, and there are no previous reports of symptomatic tubers or plants from this potato growing area. Columbia root-knot nematode most likely represents a recent introduction into northwestern New Mexico. Additional information regarding distribution of this nematode within the region is needed.