**Green June Beetles** (*Cotinis nitida*) are large, metallic green scarab beetles common in the eastern United States. They are similar to the Fig Beetle but are primarily known as nuisance and turf pests. The adults are often seen buzzing clumsily near the ground and feed on ripe, soft fruits and tree sap. The larval stage (**grub**) is a significant pest of lawns and turfgrass, where it burrows just below the soil surface, causing damage by rooting up the grass as it crawls.
Taxonomy and Classification
Green June Beetles belong to the family Scarabaeidae (scarab beetles) in the order Coleoptera. They undergo complete metamorphosis. They are closely related to the destructive Japanese Beetle but are distinct in their larger size, life cycle, and feeding habits. They are active during the day, unlike many other scarabs.
Physical Description
The adult Green June Beetle is a large, stocky beetle, $3/4$ to $1$ inch long.
- **Appearance:** Striking metallic green on the top, often with yellowish-brown margins and a prominent golden-green underside.
- **Flight:** The buzzing flight is loud and often close to the ground. Like the Fig Beetle, they fly with their hardened wing covers (elytra) down.
- **Larvae (Grubs):** Large, up to $2$ inches long, fat, creamy white, and C-shaped. They are unique among common turf grubs for their unusual habit of crawling on their **backs** when exposed on the soil surface.
Distribution and Habitat
Green June Beetles are common in the eastern half of the United States. Their habitat is lawns, pastures, orchards, and areas rich in decaying organic matter. The larvae thrive in soil, especially those heavily amended with manure, compost, or decaying wood, which is their primary food source.
Behavior and Damage
The beetle typically has one generation per year, with the larval stage overwintering. Adults emerge in early summer (June and July) to feed and lay eggs.
Damage is twofold:
- **Adult Damage:** Adults feed on soft, ripe fruits (e.g., peaches, grapes, berries) by boring into the flesh. They also feed on sap oozing from tree wounds. While minor, they are a significant nuisance pest in gardens.
- **Larval Damage (Primary Concern):** The large grubs feed mostly on organic matter, not grass roots. However, as they crawl on their backs just below the soil surface, their large movements **uproot and loosen the turf**, which is then easily pulled back, causing brown patches. They often come to the surface at night.
Management and Prevention
Control focuses on physical removal and modifying the soil environment.
- **Cultural Control:** Reduce the amount of excessive organic matter (compost, deep mulch) in the lawn and garden, as this attracts egg-laying females.
- **Mechanical Control:** The large grubs are sensitive to heat and come to the surface when warm, soapy water is applied to the turf, allowing for easy collection and destruction.
- **Biological Control:** Apply **milky spore disease** (*Paenibacillus popilliae*) or beneficial nematodes (*Heterorhabditis* spp.) to the soil, which are effective biological controls for various grubs.
- **Adult Control:** For high-value fruit, physical exclusion (netting) or trapping (fermenting fruit baits) is preferred over chemical sprays, as the adult stage is short-lived.
Conservation and Research
Green June Beetles are managed as significant turf and nuisance pests. Research focuses on optimizing the timing and application of biological controls and improving trapping methods based on their unique flight and feeding behaviors.