Nicole Keim, one of our 2018 Plains Pest Management Field Scouts, is dipping her toe into the world of entomology and ‘trying the profession on for size.’ We are helping her all we can to see the many sides of entomology. One of her summer duties will be to learn about and then educate about insects of interest to the general public. She will research this insect and then share fun facts for you to amuse and educate. Please help me welcome Nicole for her first awesome effort here;
June Beetle, Nicole’s “bug of the week”
By Nicole Keim, 2018 Plains Pest Management Field Scout
June beetles, also known as June bugs, May beetles, or daw bugs, are a type of beetle native to North America that draw their name from their well-known late spring/ early summer emergence time. June beetle grubs are voracious destroyers of grass and turf crops and a scourge to golf courses and corn fields alike. Although there are currently no chemical solutions for June beetle infestations, the beetles are easy to identify in both their larval and adult life stages.
A June beetle starts its life as an egg laid 1-5 inches beneath the surface of the soil in late spring or early summer. In 2-3 weeks the eggs hatch into larva that feed primarily on the roots of grasses until fall, when the larva burrow beneath the frost line to wait out the winter (some types of June beetle larva will do this for as many as five years!). In the spring, the larva will return to near the soil surface, grow, and pupate. In late summer, the beetle will reach its adult stage, burrow for another winter, and emerge from the soil to feed on foliage and reproduce.
Identification of the June beetle is easy, partially thanks to their commonality. In the larval stage the grub can be recognized as a white grub ½ to 1 inches in length with six legs, a brown head, and a body curled into a C shape. June beetle grubs can be quickly discerned from other white grubs by the two rows of small hairs on the underside of the last body segment. An adult will be an oval shaped, reddish- or blackish-brown beetle ½ to 5/8 inches in length. Males will be the ones found flying around porch lights at night, while females will more likely be found crawling along the ground.
June beetles do the brunt of their damage to lawns and gardens while in the larval stage. The grubs favor the roots of grasses and grains such as corn, sorghum, pasture grasses, wheat, and potatoes, while leaving other types of plants largely unaffected. Severely affected sod or lawn grass can be rolled from the ground like a carpet to expose the grubs beneath. It is also common to find grubs while gardening or pulling weeds, especially if you’re working around one of their preferred foods.
While the grubs can damage lawns, neither the larva nor the adult are dangerous in themselves (in fact, the grubs can be eaten as a survival food!). Overall, as long as you aren’t managing a golf course or farming corn or sorghum, these bugs are a nuisance at worst. At best, they can be a fun learning opportunity, an interesting light show, or even a quick snack if you’ve got a strong stomach.
Metcalf, C. L., Flint W. P. “Destructive and Useful Insects.” Theirs Habits and Control, R. L. Metcalf, McGraw Hill Book Company, 1962, pg 503-506
Agriculture Yearbook Committee. “Insects.” The Yearbook of Agriculture 1952, United States Department of Agriculture, 1952, pg 583-584
Borror, Donald J., Triplehorn, Charles A., Jonson, Norman F. “An Introduction to the Study of Insects.” Sanders College Publishing, 1989, pg 423-424