Mysterious holes in yards sometimes appear without a guilty party in sight. At times, patches of yard might implode from decaying roots, leaving holes, especially following heavy rains. Other times, the culprits are bugs that dig upward to emerge from grass or downward to deposit eggs or shop their prey. Hole sizes and also other telltale signals leave clues that help you identify your own digger.
Although actual bugs belong just to the taxonomic order called Hemiptera, common use labels any creepy-crawly creature a “bug.” Bed bugs, water bugs and stink bugs properly carry the “bug” moniker since they belong to the order Hemiptera. This group is set apart from different orders, in part because members possess morphological differences and undergo incomplete metamorphosis. But in layman’s terms, bees, beetles and ants can also be bugs. Many of these common bugs are accountable for digging holes in lawns.
Cicadas and Their Killers
Dog-day cicadas emerge in the ground each year in late summer following two- to five-year life cycles. Periodical cicadas have the longest life cycle of almost any North American insect, emerging every 13 or 17 decades, based on species. As they get to the soil surface, then they dig out, leaving a 1/2-inch-diameter hole. Cicada killers are wasps that hunt cicadas and bite them, causing paralysis. Female wasps dig holes in yards into which they pull cicada prey, then lay an egg on it. The hatched larva feed the cicada. Wasps leave holes around 1 inch in diameter that often have drag marks beside them in cicada bodies.
Bees and Beetles
Some mammals damage lawns by digging holes and mounding soil. Called ground mammals, or solitary mammals, these bugs excavate chambers in which they live and lay their eggs. Holes could be around 1/2 inch in diameter, surrounded by mounds of soil up to two inches high. June beetles and Japanese beetles burrow into soil to lay their eggs. Holes at the entrance to their tunnels might be the size of nickels, with mounds of soil and fecal matter around them.
Ants and Crickets
Ants dig holes in lawns that are usually only 1/4 inch in diameter, but with soil mounds circling them that can stretch up to 3 inches across. While their tunneling aerates soil, it might also kill patches of grass in which entrance holes are assembled. Mole crickets are so-named since they tunnel underground like moles and make burrows using their shovellike front legs. Infestations can destroy plant roots and hurt sections of turf as well as their tunnels, which can extend 20 feet in one night.