Incidence and influence of plant-parasitic nematodes in southern Illinois peach orchards.
The frequency, distribution and impact of plant-parasitic nematodes in southern Illinois peach orchards were determined. Nine plant-parasitic nematode genera were detected comprising 11 species: Helicotylenchus platyurus, Helicotylenchus pseudorobustus, Hoplolaimus spp., Meloidogyne spp., Mesocriconema xenoplax, Paratylenchus dianthus, Paratylenchus projectus, Pratylenchus penetrans, Pratylenchus vulnus, Tylenchorhynchus annulatus, Tylenchorhynchus claytoni, Tylenchus hamatus and Xiphinema americanum. Generally, Helicotylenchus, Mesocriconema, Paratylenchus, and Xiphinema were found at the highest densities. In the Prunus rootstock evaluation, growth and yield reductions of the scion 'Redhaven' depended on the rootstock and were associated with nematode population densities. Xiphinema populations were most closely linked to reductions in 'Redhaven' fruit yield and plant growth across a wide range of rootstocks. Our results indicate that Mesocriconema, Pratylenchus, and Xiphinema maintain populations that can limit peach production in southern Illinois.