Poster: Diseases of Plants: New & Emerging Diseases
First detection of the stubby root nematode Paratrichodorus allius on potato in North Dakota and on sugarbeet in Minnesota
G. Yan (1), A. Plaisance (2), D. Huang (1), Z. Handoo (3) (1) North Dakota State University, Department of Plant Pathology,, U.S.A.; (2) North Dakota State University, Department of Plant Pathology, U.S.A.; (3) USDA-ARS, Nematology Laboratory,, U.S.A.
Stubby root nematodes (SRN) are migratory ectoparasites that feed on roots, transmit tobraviruses and cause significant crop loss. In 2015, 49 soil samples were collected from a potato field in Sargent County, ND of which seven contained SRN with population densities ranging from 135 to 300/kg soil. Subsequently, 13 soil samples were collected from a sugarbeet field in Clay County, MN and six of them had SRN from 200 to 1,000/kg soil. Individual SRN were examined morphologically and molecularly for species identification. The specimens from both potato and sugarbeet fields were identified as Paratrichodorus allius. Observations of female morphological characteristics critical for identification included rod like/oval and well separated vaginal sclerotization, onchiostyle 42-45μm, absence of lateral body pores, and small ventral pharyngeal overlap. DNA was extracted from single nematodes. D2/D3 region of 28S rRNA, partial 18S rRNA and ITS1 rDNA were amplified and PCR products were cloned and sequenced. The consensus sequence from each region was deposited into GenBank and compared with known sequences. The sequence information supported the identity as P. allius. P. allius is known to be the prevalent vector of Tobacco rattle virus causing potato corky ringspot disease. Until now, problems with infestations of SRN on sugarbeet have been confined to parts of Europe, California and Idaho. This represents the first occurrence of P. allius in North Dakota and Minnesota.