Asked May 04, 2021, 2:25 PM EDT
I think I've got a problem with grubs. I've seen Japanese beetles in past summers, though hardly any last year.
Two years ago I saw damage from grubs and I treated my lawn with both milky spores and nematodes and that seemed to be effective.
Last year I had a couple of smaller brown patches.
This spring the patches are still there and seem to be growing in size already - unless the damage was done last summer and it's just more visible now.
I was just looking at the Japanese beetle and grub page. It doesn't suggest anything that I can do now. Is there anything? Should I bother adding some topsoil and trying to grow grass now in the dead spots without trying to get rid of the grubs?
Hennepin County Minnesota
The grubs are too big now to kill with chemicals. They work best in late July/August when the grubs are very small. Yes, it is a good time to repair the lawn as you suggested. Be ready to treat the new batch in late summer.