I'm seeing a lot of articles on Beneficial Nematodes. They discuss use for Japanese Beetles, Codling Moth, grubs in general. When do you apply them? Do they survive winter in zone 5? When to reapply? What are the cons?
Marshall County Iowa
I would suggest that you contact Dr. Erin Hodgson at Iowa State University Extension and Outreach. Her specialty area is crop protection and insects. The link to her contact information is below.