Effects of Hirsutella minnesotensis and N-Viro Soil® on populations of Meloidogyne hapla

Abstract

This study was conducted to determine the effects of Hirsutella minnesotensis (Hm), an endoparasitic fungus, and N-Viro Soil® (NVS), a recycled municipal biosolid, on Meloidogyne hapla greenhouse populations from Rhode Island (RI), Connecticut (CT), Geneva, New York (NYG), Lyndonville, New York (NYL), and Michigan (MI). In a greenhouse experiment, tomato (cv. Rutgers) seedlings were inoculated with 0 or 600 eggs of each nematode population and exposed to Hm mycelium (0 or 0.1 g fresh) and NVS (0 or 1 g 0.1 L⁻¹ of soil) in a factorial design. Hirsutella minnesotensis reduced nematode densities by 31–83% across nematode populations in one test, but only slightly reduced densities of NYG and CT populations in another test. NVS reduced nematode densities by 33–92% across populations in two repeated tests. The combination of the two agents resulted in greater nematode reduction compared with Hm alone, but not compared with NVS alone. Across all Hm and NVS treatments, reduction of nematode densities were generally greater in NYG, CT, and RI than in MI and NYL populations. This study demonstrated that Hm and NVS may be used to suppress different M. hapla populations.

Keywords:

• Biological control agent
• Hirsutella minnesotensis
• Meloidogyne hapla
• methyl bromide alternatives
• nematophagous fungus
• root-knot nematode
• tomato

Acknowledgments

We thank T. Kerchkof and R. Pereault for technical assistance, Drs G. Abawi (NY), J. A. LaMondia (CT), and N. A. Mitkowski (RI) for providing the nematode populations, Dr T. Powers, University of Nebraska, for confirming the populations of M. hapla by DNA analyses, and the two anonymous reviewers for their thorough review and thoughtful comments and suggestions for revising the manuscript. The project was funded in part by a grant from USDA/CGP/MBT Program (02-51102-01948) and N-Viro International, Toledo, OH, to the last author.