Switchgrass (Panicum virgatum L.) has attracted recent attention as a potential biofuel crop, but stand establishment can be difficult. Plant-parasitic nematodes, as well as other soil borne pathogens, may contribute to this problem in the South Central United States. In a survey of five-year-old switchgrass variety trials, plant-parasitic nematodes were identified from samples collected after fall biomass harvest. Plot locations included Clinton, LA, Hope, AR, College Station, TX, and Stephenville, TX. Twice as many nematode species were identified at Hope and Clinton as at College Station or Stephenville. Xiphinema americanum and Tylenchorhynchus spp. (T. capitatus and T. ewingi) were found at all locations. Paratrichodorus minor and Criconemella ornata were found in three of four sites. Hoplolaimus magnistylus, Pratylenchus zeae, Helicotylenchus spp. (H. dihystera and H. digonicus), Meloidogyne spp., and Paratylenchus spp. were identified from some sites. Upland morphological types of switchgrass supported greater densities of Helicotylenchus spp. than lowland types at Clinton and greater densities of Pratylenchus, Helicotylenchus, and Tylenchorhynchus spp. at Hope. Lowland types appeared to be better hosts for Tylenchorhynchus spp. at Stephenville and for P. minor at Hope. Differences in nematode population density among switchgrass genotypes were found for several nematode species, and in some cases, the nematodes were correlated with decreased stand persistence or dry matter yield.
