Our yard is approx 90×90 and we have thoundands of digger bees. How deep do they burrow? What is the best way for us to get rid of them?
In general digger bees will only tunnel 8-12 inches. Though it's common to have hundreds and sometimes even thousands in one yard, they are solitary. This means their nests only have one female and several eggs. When their young are able to lay eggs, they'll attempt to do so where they themselves were born. The net result (when left untreated) is a yard full of digger bees. It sounds like this might be the case in your situation.