First Report of Columbia Root Knot Nematode (Meloidogyne chitwoodi)
in Potato in Texas. A.L.Szalanski,
P.G.
Mullin, T.S. Harris, and T.O. Powers.
Department of Plant Pathology,
University of Nebraska, Lincoln 68583. Plant
Disease 85:442. (2001)
Columbia root-knot nematode, Meloidogyne chitwoodi
Golden
et al. (1980) was identified from potatoes, Solanum tuberosum L.,
collected from Dallam county, Texas in October 2000. Seed potatoes are
the most likely source for this introduction. This nematode is currently
found infecting potatoes grown in California, Colorado, Idaho, New Mexico,
Nevada, Oregon, Utah, and Washington. Some countries prohibit import of
both seed and table stock potatoes originating in states known to harbor
M.
chitwoodi.
Lesions on the potatoes had discrete brown coloration with white central
spots in the outer 1 cm of the tuber flesh. Female nematode densities averaged
3 per cm2 of a potato section beneath the lesions. Nematodes were morphologically
identified as M. chitwoodi based on the perineal pattern of mature
females and the tail shape of juveniles per Golden et al. (1980). Using
PCR-RFLP of the rDNA ITS1 region and the mtDNA COII-16S rRNA region (Powers
& Harris 1993), individual juveniles were identified as M. chitwoodi
based on their restriction fragment patterns. This is the first report
of Columbia root-knot nematode infecting potatoes in Texas. The distribution
of this nematode in potato fields throughout central United States should
be determined. |