Impact of Pratylenchus penetrans (Nematoda) on Heterodera spp. resistant cultivar performance

Heterodera glycines (soybean cyst nematode) and H. schactii (sugar beet cyst nematode) are common pathogens of soybeans and sugar beets in MI. In addition to co-existing, they commonly occur in sites colonized by Pratylenchus penetrans (root-lesion nematode). Species specific resistant cultivars exist for both cyst nematodes. Very little is known about the performance of these cultivars in the presence of the root-lesion nematode (RLN). The objective of this research is to evaluate the performance of resistant lines-cultivars in the presence and absence of multiple species of phytopathogenic nematodes. In the presence of RLN, soybean cyst nematode (SCN) reproduction on a PI 88788 resistant variety was significantly greater than in its absence. This was observed at three initial population densities of RLN. RLN had no impact on SCN fecundity on a cyst nematode susceptible variety. All seven PI lines used in HG typing were shown to be good hosts for RLN. Reproductive potential of PI 89772 was significantly less than that for PI 54840 or PI 437654. A sugar beet cyst nematode (SBCN) resistant sugar beet variety was field tested in Michigan for the first time in 2005 in seven field locations. Beet yields were enhanced 6-10 tons/A. A study was also conducted to determine the impact of RLN on the performance of an SBCN resistant sugar beet variety.