Pest of the Week - June Bug Beetle

The June bug  (Phylophaga sp) is a member of the Scarab family which was revered by the ancient Egyptians and isn't actually a "true" bug.  True bugs are members of the Order Hemiptera("half wings"). For members of the Order Hemiptera part of the first pair of wings is toughened and hard, while the rest of the first pair and the second pair of wings are membranous.

June bugs are memebers of the Order Coleoptera.  The name Coleoptera, derived from the Greek words "koleos" meaning sheath and "ptera" meaning wings, refers to the modified front wings which serve as protective covers for the membranous hind wings.  There are more than 400 species of June bug beetles (Phyllophaga spp.) north of Mexico, and they are difficult to distinguish.

June beetle. Photo by Laura C. Jesse
University of Iowa Extension

After mating, June beetle females dig a few inches into the soil to deposit their eggs, often near trees. Depending on the species. the grubs live underground for 1–4 years. During that time they feed on plant roots and descend much lower into the soil to overwinter.  In late spring the larvae pupate for a few weeks, within a small cavity in the soil. They emerge as adults but stay underground for another year until the following spring, when they crawl to the surface to fly, mate, and lay eggs.

Larval form of June bugs
Texas A&M
Photo by Bart Drees

June beetle grubs feed on the roots of grass.  The damage can appear as irregular yellow or dead patches.  Less severely damaged turf lacks strength and is more vulnerable to invasion by weeds.   During the second year of an infestation the damage becomes more apparent, because the grubs have reached a larger size.  The second year is the best time to apply insecticide since the damage usually isn't  extensive and an insecticide would be effective.

Additional Information

Hemiptera - Entomology for Master Gardeners - University of Kentucky

Coleoptera - NC State University

Managing Turfgrass Insects of the Northeast Part 2: Root Infesting Insect Pests- Rutgers University

May June Beetles - University of Minnesota

The Sacred Scarab - McClung Museum