Cicada killers are very large wasps, up to 1 5/8” long, that resemble gigantic hornets or yellow jackets.
Each summer we receive complaints of them menacing golfers and digging holes into the greens and bunkers. While they look formidable, they are in fact not a threat. The male wasp is territorial and will buzz around you trying to chase you away but lacks a stinger, so he is completely harmless.
The female wasp is non-aggressive but can sting if handled or stepped on with bare feet. She prefers to spend her time burrowing into the ground and hunting annual cicadas. After digging an extensive burrow up to a foot in depth, the female will find a cicada, paralyze it with her stinger and carry it back to her burrow. After placing the cicada in a chamber, she will lay an egg on it and bury the cicada where it becomes food for her young. She will repeat this process nonstop for a couple of weeks.
This is a picture of a cicada burrow on a green. Each morning the golf course crew will look for these mounds and will inject an insecticide into the hole to stop the cicada killer from causing further damage. Although the mounds are cleaned up every day, a cicada killer can complete a new burrow in less than an hour. There is no insecticide that will prevent the cicada killers from digging into a green, so all control must be done post damage. Failing to control the cicada killers causes later damage to the greens when coyotes, foxes, and crows dig up the buried cicadas for food. Therefore, when the wasps are active, crew members will watch for recent activity during the day and treat the new burrows that appear.