We first noticed this issue last year. After several weeks of effort (multiple visits by Frontline, covering with tarps, etc.) they finally went away, shortly after I sprayed ammonia into their holes in the evening. I'm not sure if the ammonia did it, if the Frontline treatments finally worked, or if they just moved on. They came back to the same place (a field next to the driveway) this year. However, I have sprayed ammonia twice already, and they do not seem to be affected. I know that they are not aggressive, but the problem is that we are trying to sell our house, and the presence of a field of bees does not add to the resale value.

Does anyone have any useful advice?

Thank you in advance.

What kind of bees?

Not sure the exact type-I was just told solitary ground bees. We're in Maryland, if that helps. Can you point me in the direction of some kind of identification key that would help me to further identify them?

They'll continue to be an issue until a heavy rain or until egg-laying season is over. Getting rid of them this year will be almost impossible. You might try using some of the yard treatment granules, which will definitely help with next year, but you will have to treat the entire field. The size of the field and the ownership of it may prohibit this due to cost or permission.

If it is practical, the organic granules that use clove oil as a repellant may, I repeat MAY, work a little faster.

As for species identification, try these sites:

Mining Bees & Ground Nesting Wasps

Ground-Nesting Wasps

What control measures you can attempt work on all the different species, so the research is mainly academic.

Thanks for the input. If a heavy rain can get rid of them, would there be any benefit to setting up a sprinkler or two in the areas? As to treating the field, that won't be a problem. It's our property, and it's not a huge field-less than half an acre. Would I find those granules at a Lowe's/Home Depot, local farm supply, etc?

Have you heard of spraying ammonia in the holes? As I said, I did that last year & shortly afterwards they left, but I can't be certain that it had anything to do with the ammonia treatment. I don't mind giving that another round, if it might help, but don't want to waste the effort if it's not going to help.

And from the links you gave me, I'm fairly certain that I'm dealing with a species of mining bees. While they may be good for the soil, they are likely not ideal when realtors bring perspective buyers to look at the property. Thanks again for the input.

I mentioned heavy rains because they will pack the dirt back down the bees have dug up, making it look less like a horror movie set.

The long term soil treatments are available at the various Home/Garden stores, I haven't checked for the organic granules as I order in bulk. If you find them, look for clove oil or Eugenol as the main ingredient.

As far as ammonia, no, I have not heard of it as either a soil treatment or a fumigant. I think last year was more of a coincidence of timing than any efficacy. It's probably a great fertilizer, though.