Selected Pacific Northwest Rangeland and Weed Plants as Hosts of Pratylenchus neglectus and P. thornei

Abstract

Smiley, R. W., Yan, G. P., and Gourlie, J. A. 2014. Selected Pacific Northwest rangeland and weed plants as hosts of Pratylenchus neglectus and P. thornei. Plant Dis. 98:1333-1340.Eighteen rangeland plants and 16 weed species were assayed in the greenhouse for efficiency as hosts of Pratylenchus neglectus and P. thornei. Hosting ability ratings were assigned using the ratio of final versus initial nematode density and by comparing the final nematode density to that of susceptible wheat controls. Good hosts of both Pratylenchus spp. included thickspike bluegrass 'Critana', smooth brome 'Manchar', seven wheatgrasses, and jointed goatgrass. Good hosts of P. neglectus but not P. thornei included two hairy vetches, western wheatgrass 'Rosana', big bluegrass 'Sherman', tall wheatgrass 'Alkar', green foxtail, kochia, large crabgrass, palmer amaranth, redroot pigweed, tumble mustard, and wild oat. Good hosts of P. thornei but not P. neglectus included hard fescue 'Durar', sheep fescue 'Blacksheep', downy brome, and rattail fescue. Poor or minor hosts of both Pratylenchus spp. included two alfalfas, dandelion, horseweed, lambsquarters, prostrate spurge, and Russian thistle. These assays will provide guidance for transitioning rangeland into crop production and for understanding the role of weeds on densities of Pratylenchus spp. in wheat-production systems.Agricultural fields in low-precipitation regions of the Pacific Northwest (PNW; southern Idaho, eastern Oregon, and eastern Washington) are frequently infested by one or more species of Pratylenchus (12,31,38). Approximately 90% of rainfed production systems are infested by P. neglectus (Rensch) Filipjev Schuurmanns & Stekhoven, by P. thornei Sher & Allen, or by mixtures of these two species. The occurrence of P. thornei is more geographically restricted than for P. neglectus. Yields of rainfed wheat (Triticum aestivum L.) in low-precipitation environments (<400 mm annually) are often inversely correlated with preplant densities of these nematodes (29,35,36). Both species have reduced grain yields by as much as 60% in PNW rainfed wheat (29,35,36) and are estimated to reduce profitability of wheat production in the PNW by at least $51 million annually (28).More than one million hectares of former wheat-producing land on 10,321 farms in Idaho, Oregon, and Washington are currently maintained under contracts to the USDA Natural Resource Conservation Service's Conservation Reserve Program (USDA-NRCS-CRP) (46). Ten-year CRP contracts require the planting of mixtures of three to five native grasses and one or more forbs or legumes adapted to local environments and best suited to wildlife in that area. Species and cultivars meeting the minimal requirement are specified in the contract. Upon expiration of a contract, the producer may continue to maintain the land as rangeland without federal funding, return the land to crop production, or negotiate another CRP contract. Land retired from a CRP contract in the inland PNW is mostly returned immediately to wheat production. In the ...

Molecular determination of root-knot nematode species, Meloidogyne spp. Goeldi, 1892 (Tylenchida: Meloidogynidae) infesting weeds in kiwifruit orchards in Türkiye

“…Taraxacum officinale was found to be infested by M. hapla at one location in the present study. Kornobis & Wolny (1997) and Smiley et al (2014) reported some other groups of nematodes associated with this weed, and Gaskin & Crittenden (1956) reported it as a host of M. hapla. Doucet et al (2000) reported it as a good host that may enhance the spread of M. hapla.…”

Duplex real-time quantitative PCR for simultaneous detection and quantification of Pratylenchus neglectus and P. thornei

“…More than 100 Pratylenchus species have been described (Janssena et al 2017). Of these species, P. neglectus and P. thornei that damage various plants including the main grain crop of wheat have been noted in many countries and regions (Castillo and Vovlas 2007;Smiley et al 2014;Dababat et al 2016), mixed population was even found within the same fields (Smiley et al 2014). Wheat cultivars are vary in tolerance or resistance respect to P. neglectus and P. thornei infection (Yan et al 2008;Dababat et al 2016), accurate identification and early detection of these nematodes are therefore important for controlling them by using crop rotation or growing resistant/tolerant cultivars.…”

Reproduction of Pratylenchus zeae on Weeds

“…Different species of weeds have been recognized as host plants for Pratylenchus spp. in diverse regions of the world, contributing to an increase of nematode populations in the soil, thus constraining the establishment of agricultural cultures (Kutywayo and Been, 2006;Bélair et al, 2007;Smiley et al, 2014). In this context, this work aimed to assess the reproductive capacity of P. zeae in different species of weeds.…”