Impact of Arbuscular Mycorrhizal Species on Heterodera glycines

Soybean cyst nematode (SCN, ) is a widely occurring pest and the leading cause of soybean yield losses in the U.S.A. There is a need to find additional SCN management strategies as sources of SCN resistance have become less effective in managing SCN populations. Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with roots of most plants including soybean. Research has shown that AMF can reduce disease severity in plants caused by pathogens and pests, including plant parasitic nematodes. The goal of this study was to evaluate the impact of AMF on SCN cyst production, SCN juveniles in roots, and SCN egg hatching. In one experiment, all five AMF species tested ( , , , , and ) reduced ( < 0.05) the number of cysts on soybean roots by 59 to 81%, compared with soybean roots not inoculated with AMF. Inoculation with reduced SCN J2-J3 stage juveniles in soybean roots by 60% at 7 days post inoculation. A separate experiment showed that egg hatch was reduced ( < 0.05) in the presence of spores and their exudates by 27% and 62%, respectively. Further research is needed to evaluate the potential usefulness of AMF in field conditions and to determine the usefulness and potential of the exudates associated with SCN hatching suppression by . Making AMF a more effective biological control agent would provide another management tool to reduce the negative impact of SCN on soybean production.