Burrowing in lawn

Asked August 8, 2018, 2:41 PM EDT

What sort of critter will dig a 1" diameter burrow in the lawn and displace soil that looks like a pile of pebbles? How concerned should I be?

New Castle County Delaware

1 Response

This looks like it could be a hole dug out by a female cicada killer. Females dig holes into the ground that can be as deep as 18 inches and 30 inches or more long. Side chambers are also dug out and she uses those as brood chambers for her offspring. After digging out a chamber, the female leaves the hole searching for a cicada to bring back. She stings a cicada, brings it back to her brood chamber and lays an egg on the paralyzed cicada. The egg hatches and the larva eats the cicada. Next year, wasps will leave this chamber and start the process over. Female cicada killers like areas that are sunny, weedy or thin of grass, and drain well. Females rarely sting (I've dug up their nests before and had the female crawling all over my legs but didn't get stung), and males (they will fly towards you to drive you away) cannot sting. I would not be too concerned. This wasp is considered a solitary non-aggressive wasp. There are few products available to manage this insect and even those that are available do not provide much control.