How do you eliminate the nests (in the ground) of the Cicada killing wasps? We have multiple nests in the ground under the storage building (about 15'x15') in our back yard. They emerge in mid July and zoom around real aggressively. The local extension office suggested Sevin dust or granules, but they did not work. Any suggestions?? I cannot plow or pour anything down in the holes because they are underneath the storage bldg, I can only toss the granules underneath unless I get another good suggestion. Thanks.

Sandi Dale Nelson