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In June 2006, stunted and chlorotic plants were observed in large patches in two 40.5-ha fields of dryland peas (Pisum sativum) in Latah County, Idaho, which resulted in 90 and 75% crop loss. In the same region, a 121.4-ha field of dryland lentils (Lens culinaris) also had plants showing poor growth, wilting, and yellowing in large patches, which resulted in 40% crop loss. Two species of lesion nematodes (Pratylenchus neglectus and P. thornei) and one species of pin nematode (Paratylenchus hamatus) were extracted from rhizosphere soil and the roots of symptomatic plants from these fields. In a subsequent survey of seven dryland pea fields, under cv. Columbian, in Latah and Nez Perce counties and one dryland pea field, under cv. Small Sieve, in Latah County, plant samples had means of 551 and 2,178 mixed species of lesion nematodes per gram of dry root, respectively. Plant samples from 12 lentil fields in Latah County, six planted with cv. Red Chief and six with cv. Pardina, had means of 279 and 987 mixed species of lesion nematodes per gram of dry root, respectively. Soil samples from the same fields had a mean of 628 and 671 pin nematodes, Paratylenchus hamatus, per 250 cm3 soil for Red Chief and Pardina, respectively. Lentils cv. Pardina and peas cv. Columbian were planted separately in six pots, five seeds per pot containing 250 g of infested soil brought from the field to the greenhouse. Fumigated sandy loam soil was used as control. These assays were repeated three times. In addition, peas and lentils were planted to pots infested singly with each of the three nematode species. For this assay, nematodes were extracted from field soil, surface sterilized, and used to infest 250 g of fumigated sandy loam soil at two nematodes per gram of soil. Six plants per nematode species and an uninoculated control were used in the greenhouse assays, which were repeated three times. Nematodes in all of the assays reduced plant growth in comparison with controls; an average of 50 to 70% reduction in plant height was noted. The lesion nematode populations increased in all pots. The greenhouse assays verified the negative impact of these nematodes on growth of dryland peas cvs. Columbian and Small Sieve and lentils cvs. Red Chief and Pardina. P. neglectus, P. thornei, and Paratylenchus spp. previously have been reported from the semi-arid Pacific Northwest (1). However, to our knowledge, this is the first report attributing plant growth and yield reduction of certain cultivars of lentils and peas to these two species of lesion nematodes and pin nematodes, identified to species level as Paratylenchus hamatus. Reference: (1) R. W. Smiley et al. J. Nematol. 36:54, 2004.

Dagger nematode, Xiphinema rivesi Dalmaso, 1969 reportedly transmits several viruses in North America and Europe (2) leading to severe yield reduction in crops. Soil samples were collected in March 2013 during a survey of cherry orchards in Chelan County, WA; these historically suffer from cherry rasp leaf disease, caused by Cherry rasp leaf virus (CRLV) (genus Cheravirus). Soil samples were transported to the WSDA nematology laboratory in Prosser, WA, where 250-cc subsamples were processed using sucrose centrifugal flotation (1). Dagger nematodes were hand-picked and stored in 0.1% sodium chloride before being sent to the USDA-ARS Nematology Laboratory in Beltsville, MD, for morphological and molecular identification. The morphological and molecular analysis of adult females identified the dagger nematode species as Xiphinema rivesi Dalmaso, 1969 (4). Morphological characters used for identification included female body, and total stylet length (odontostyle and odontophore), location of guiding ring from oral aperture, head and tail shape, various tail measurements, and vulva percentage in relation to body length. Measurements of females (n = 10) include a mean body length of 1,902 ± 162.4 (1,832 to 2,203) μm, odontostyle 83 ± 3.5 (80 to 90) μm, odontophore 54.8 ± 4.2 (50 to 65) μm, total stylet 137.8 ± 4.2 (130 to 145) μm, guiding ring from oral aperture 70 ± 5.1 (60 to 75) μm, tail 30.8 ± 2.5 (27.5 to 35.0) μm, body diameter at anus 24.7 ± 1.7 (22 to 28) μm, J (hyaline portion of tail) 6.0 ± 0.9 (5.0 to 7.5) μm, body diameter at beginning of J 8.5 ± 1.0 (7.5 to 10.5) μm, body diameter at 5 μm from tail terminus 7.5 ± 0.2 (7.0 to 8.0) μm, and V% 52.2 ± 1.8 (49.4 to 55.0) μm. Molecular diagnosis of X. rivesi was confirmed after DNA was extracted from two individual nematodes by mechanical disruption with a micro knife in 20 μl worm lysis buffer containing 500 mM KCl, 100 mM Tris-Cl (pH8.3), 15 mM MgCl2, 10 mM dithiothreitol (DTT), 4.5% Tween 20, and 0.1% gelatin. DNA extracts were stored at –80°C until needed, then thawed, 1 μl proteinase K (from 2 mg/ml stock) was added, and the tubes were incubated at 60°C for 60 min, followed by 95°C for 15 min. The 28S large ribosomal D2-D3 expansion segment was amplified with D2A (5′-ACAAGTACCGTGAGGGAAAGTT-3′) and D3B (5′-TCGGAAGGAACCAGCTACTA-3′), and the internal transcribed spacer (ITS) region was amplified with primers TW81 (5′-GTTTCCGTAGGTGAACCTGC-3′) and AB28 (5′-ATATGCTTAAGTTCAGCGGGT-3′), as previously described (3). To verify the identity of the sequences generated from PCR, sequenced products were subjected to a database search using BLAST. Sequences from the 28S region were >99% identical to several sequences of X. rivesi sampled from Spain (GenBank Accessions JQ990038, JQ990039, HM921357, and HM921358). Sequences from the ITS region were 97 to 98% identical to X. rivesi sequences (FR878063 to FR878066) obtained from the host Vitis vinifera from Italy. To the best of our knowledge, this is the first report of this nematode from the Washington. The quick and persistent spread of CRLV in most of the orchards visited calls for concern and there is need for urgent control measures against this vector nematode. References: (1) W. R. Jenkins. Plant Dis. Rep. 48:692, 1964. (2) S. Sirca et al. Plant Dis. 91:770, 2007. (3) Skantar et al. J. Nematol. 44:58, 2012. (4) M. R. Wojtowicz. et al. J. Nematol. 14:511, 1982.

The potato cyst nematode, Globodera pallida (PCN), a restricted pest in the United States, was first reported in Bingham and Bonneville counties of Idaho in 2006 (1). The U.S. government and Idaho State Department of Agriculture hope to eradicate it from infested fields. Eradicating PCN will require depriving the nematodes of their hosts over a protracted time period. Functional eradication might be achieved with relatively high, proven to be efficacious dosages of soil fumigants. The presence of host weeds of PCN can play a significant role in the success of the eradication program. To determine the host status of common weeds found in potato fields of the Pacific Northwest, host suitability tests were conducted in a secured greenhouse located at the University of Idaho at Moscow. Reproduction of PCN on nine weeds including hairy nightshade (Solanum physalifolium formerly S. sarrachoides) and cutleaf nightshade (S. triflorum) (biotypes from Idaho and Washington), black nightshade (S. nigrum) (Washington biotype), bittersweet nightshade (S. dulcamara) (Idaho biotype), redroot pigweed (Amaranthus retroflexus), kochia (Kochia scoparia), and common lambsquarters (Chenopodium album) were compared with reproduction on Desiree, Russet Burbank (known hosts), and Santé (poor host) potatoes (S. tuberosum). Plants were grown in 10-cm-diameter clay pots containing sandy loam soil previously fumigated with methyl bromide and inoculated with 10 to 150 cysts that were either collected from infested fields or raised in the secured greenhouse (ample diapause period elapsed). Treatments were replicated five times and each trial lasted 3 months. Cysts were extracted from soil with a Fenwick can, and the reproductive factor (RF = final cyst count ÷ initial inoculum) was determined. While both biotypes of hairy nightshade were suitable hosts of PCN (161–668 ÷ 150; RF = >1), cutleaf biotypes, black, and bittersweet nightshades were poor hosts (1–108 ÷ 150; RF = 1) proved to be suitable hosts and Santé (1–20 ÷ 150; RF = Reference: (1) A. M. Skantar et al. J. Nematol. 39:133, 2007.

Meloidogyne chitwoodi Golden et al. is a serious pest of potato (Solanum tuberosum L.), and is widespread in the Pacific Northwest United States. M. chitwoodi is currently reported to consist of two host races and one pathotype (2,3) that are not distinguished morphologically. Host race 1 reproduces on Chantenay carrot but not on Thor alfalfa and host race 2 reproduces on alfalfa but not on carrot. Both races fail to reproduce on roots of S. bulbocastanum, a wild potato species used as a source of resistance in our breeding program (1). The resistance to race 1 in S. bulbocastanum is attributed to Rmc1(blb) gene. Pathotype 1 of race 2 breaks resistance and reproduces on S. bulbocastanum (2). We have tested resistant breeding lines repeatedly in Prosser, WA field plots infested with MC race 1 and harvested tubers free from M. chitwoodi damage. In 2004 however, tubers of some resistant lines were damaged by the M. chitwoodi population that did not cause damage in the past. Populations of M. chitwoodi were established on tomato by adding peels obtained from the infected tubers of resistant lines. The reproductive factor, final number of eggs ÷ initial inoculum, of the new population was determined on five replications of 3-week-old Chantenay carrot and Thor alfalfa. Five thousand eggs were extracted from nematode cultures reared on tomatoes and then were added around the root system of the test plants. The plants were maintained in the greenhouse for 55 days before the nematode eggs were extracted and RF (reproductive factor = final/initial population) values determined. Like the MC race 1, new populations reproduced on Chantenay carrot (RF > 1) but failed to reproduce on Thor alfalfa (RF < 0.1). Unlike MC race 1, the new populations reproduced on roots of all breeding lines that carried Rmc1(blb) gene (RF > 1). These results suggest that the selected population of M. chitwoodi in the Prosser site is a new pathotype, which is designated pathotype 1 of MC race 1. References: (1) C. R. Brown et al. Am. J. Potato Res. 83:1, 2006. (2) H. Mojtahedi et al. J. Nematol. 30:506, 1998. (3) G. S. Santo et al. Plant Dis. 69:361, 1985.

Leaves of the rapeseed (Brassica napus) cultivar Jupiter used as a soil amendment effectively reduced Meloidogyne chitwoodi population densities at the zone of incorporation. Soil in the zone of incorporation was protected from nematode colonization for 6 wk. Stem and root tissues of rapeseed were also effective when homogenized before being used as an amendment. Greenhouse-grown plants accumulated more glucosinolates and became more effective in suppressing M. chitwoodi with age (.)

Twenty clones showed nonhost reactions (R=