What Do June Beetles Eat?
June beetles, also commonly known as June bugs, have different feeding habits depending on their life stage. The larvae, often called white grubs, primarily feed on the roots of grasses and other plants. This subterranean feeding can damage lawns, pastures, and crops by reducing the plants’ ability to absorb water and nutrients. They are particularly fond of turfgrass roots but may also consume roots of corn, vegetables, and ornamental plants.
Adult June beetles, which emerge above ground typically in late spring to early summer, feed on the foliage of trees and shrubs. They are known to consume leaves of oaks, maples, elms, and fruit trees, sometimes causing noticeable defoliation when populations are high. The adults generally feed at night and are attracted to lights, which is why they are often seen swarming around outdoor lights.
Control strategies often target the larval stage, since feeding underground can be harder to detect until plant damage is evident. Proper lawn maintenance, beneficial nematodes, and insecticides are common approaches for managing larval populations, while adult beetles are less frequently the primary target unless they are causing significant defoliation.
Do June Beetles Eat Plants?
June beetles (adult and larval stages) target different parts of plants, so the plants they affect vary depending on the stage:
Larvae (white grubs) – root feeders
The larvae live underground and feed on roots, primarily of grasses and other low-growing plants. Plants most at risk include:
Turfgrass: Kentucky bluegrass, fescue, ryegrass, Bermuda grass, and St. Augustine grass.
Ornamental plants and garden crops: Corn, beans, potatoes, and various vegetables when larvae densities are high.
Pasture plants: Alfalfa and clover, especially in areas with sandy soil where grubs thrive.
Damage from larvae usually shows as brown, thinning patches of grass or plants that wilt and die despite adequate watering. Birds digging in the soil can also indicate grub presence.
Adults – foliage feeders
Adult June beetles feed above ground at night on the leaves of trees and shrubs. Plants most commonly affected include:
Deciduous trees: Oak, maple, elm, willow, birch, and fruit trees like apple, cherry, and peach.
Shrubs: Rose, rhododendron, and other ornamental shrubs.
Occasionally vegetables: Corn leaves may be nibbled if adults are present in large numbers.
Adult feeding is generally not lethal to trees but can cause aesthetic damage and, in heavy infestations, stress young plants.
What Else Do June Beetles Eat?
June beetles are primarily herbivorous, but their diet can vary slightly depending on species, location, and life stage:
Larvae (grubs):
Almost exclusively feed on roots and underground plant material, particularly grasses, but in some cases they may chew on roots of flowers, vegetables, and ornamental shrubs.
They occasionally consume decaying organic matter in the soil, which can supplement their diet when preferred roots are scarce.
Adults:
Mainly feed on leaves and foliage of deciduous trees and shrubs.
Some species are known to nibble on fruit, particularly soft or overripe fruit, though this is less common.
Adults may also feed on flower petals or buds if foliage is limited, but leaves are preferred.
Other potential minor food sources:
In rare situations, adults may ingest pollen or nectar, but they are not significant pollinators or nectar feeders.
They can occasionally feed on plant sap if leaves are damaged.
June beetles stick to plant material—roots for larvae, leaves (and occasionally fruit) for adults. They are not predators and do not feed on other insects.