Green June beetle

What is green june beetle?

The green June beetle is a native scarab beetle and the biggest of the common lawn grubs. Purdue lists it as a native annual grub, and Penn State notes it is occasionally found in home lawns in Pennsylvania. The adults are hard to miss: large green beetles that fly clumsily on summer days and often bump into people.

Green June beetle grubs behave differently than other white grubs. They are about 2 inches long, wide-bodied and stay fairly straight instead of curling into a C. They live 3 to 5 inches deep during the day and come to the surface at night, crawling on their body segments and bristles; Oklahoma State notes live grubs crawl on their backs. They feed on roots and decaying organic matter, so they favor rich soil. Cornell notes the grubs tunnel through the root zone more than they feed directly on roots, and uses a low threshold of about 5 grubs per square foot.

The real lawn damage often comes from their digging: burrows and soil mounds loosen turf and dull mower blades, and Purdue says this can cause trouble at lower grub numbers than other species. The adults cause a different problem in home orchards. Oklahoma State says they are drawn to ripe and overripe fruit, gouge into it with a small horn on the head, and can spoil peaches, grapes, berries, apples and plums with their feeding, odor and droppings.

People and pets: Adults are clumsy daytime fliers that often bump into people (NC State). The scoliid wasps that hunt the grubs are not aggressive and pose no risk to people (NC State).

Signs and damage

• Small mounds of loose soil on the lawn surface, marking burrow entrances, in spring and late summer.
• Quarter-sized holes in the turf (NC State).
• Thin, loose turf that lifts easily in the 'tug test'.
• Large grubs crawling on the lawn surface at night.
• Big green beetles flying clumsily over lawns on summer days, often bumping into people.
• Adults gouging into ripe or overripe peaches, grapes, berries and other fruit; several may burrow into one peach, and their odor and droppings can spoil fruit (Oklahoma State).

Green June beetle identification: what to look for

• Adult: About 3/4 to 1 inch long and 1/2 inch wide. Upper side dull brown with green stripes or velvety green, with light brown to orange-yellow edges; underside shiny metallic green, gold or dark brown with a yellow-green tint.
• Larva: Cream-colored grub with a red-orange head and three pairs of short, stubby legs, about 2 inches long and parallel-sided. It does not curl into the typical C shape.
• Eggs: Laid in clusters of 10 to 30 in walnut-sized soil burrows, often in soil with lots of organic matter; they hatch within two weeks.
• Damage: Small soil mounds, quarter-sized emergence holes, thinned crowns and thatch, and turf that lifts easily.
• Timing: A few adults appear in late May or early June, most in mid-June; adults are common in July and August and some stay active into early October (Oklahoma State). Mounding shows in spring and late summer.

Life cycle

One generation a year. Grubs spend the winter nearly full grown in the soil, finish feeding in spring, and pupate in soil cells for 2 to 3 weeks. A few adults appear in late May or early June, most in mid-June, and they stay common through July and August. In late summer females lay clusters of 10 to 30 eggs in small soil burrows, preferring soil high in organic matter; Oklahoma State says sandy, humus-rich soil 6 to 8 inches deep. Eggs hatch in about two weeks, and grubs feed until winter, staying 3 to 5 inches deep by day and coming up at night (NC State, Oklahoma State, Purdue).

When to look: Watch for adults flying over lawns in late spring and summer. Look for soil mounds and holes in late summer and again in spring. Curative work, if needed, is usually best in August and September while grubs are small.

Green June beetle look-alikes

A few things get mixed up with it:

• Japanese beetle (Popillia japonica): Also green, but only about 1/2 inch long, with copper wing covers and white hair tufts. Grub is about 1 inch and curls into a C.
• May/June beetles (Phyllophaga spp.): Share the 'June bug' name but are reddish-brown to black and fly at night to lights. Grubs curl into a C and reach about 1 1/4 inches.

How to control green june beetle

Cultural control

• Use the tug test: pull gently on turf in damaged spots. If it lifts easily, grubs are likely feeding in the crown and upper roots (NC State).
• Sample soil with a cup cutter, shovel or sod cutter and break it apart to look for grubs (NC State).
• After any treatment, rake up grubs that die on the surface so they don't rot and smell; don't use a mower, since lots of grubs can clog it (NC State).

Biological control

• Scoliid wasps hunt white grubs in the soil, paralyze them and lay an egg on them (NC State).
• Milky spore will not help; it infects only Japanese beetle grubs.

Chemical control

NC State says curative treatment is the most common approach, best in August and September while grubs are small and near the surface. It names carbaryl as a contact product for this grub and says not to water it in, so grubs crawl through it at night. Preventive neonicotinoid or diamide products go down before eggs are laid, timed to peak adult flight, and only where green June beetle damage has happened before. Rutgers notes imidacloprid is less effective on this species. Use only products labeled for this use; the label is the law.

Use only products labeled for this pest and this site; the label is the law. For trees, work with an ISA Certified Arborist. If you hire someone to apply pesticides, make sure they hold your state’s pesticide applicator license; the rules for each state are in our pesticide applicator license guide.

Prevention

• Keep an eye on lawns with rich, high-organic soils, which egg-laying females prefer.
• Save preventive products for lawns that have had green June beetle damage before; NC State advises against using them where damage is unlikely.

When to call a pro

Call a licensed pesticide applicator (see our pesticide applicator license guide) if mounding and tunneling are tearing up a lawn or interfering with mowing.

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Questions about green june beetle

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