Rose chafer

Insect

Rose chafer

Macrodactylus subspinosus (F.)

Coleoptera: Scarabaeidae

Distribution: Southeastern Canada and in most fruit-growing states in eastern US.

Photos

Adult feeding on fruit surface. Peter McGhee, MSU
C

The rose chafer is a light tan beetle with a darker brown head and long legs. It is about 12 mm long. There is one generation per year. Larvae are larger C-shaped grubs that live in the soil. Adults emerge from the ground during late May or June, near grape bloom time, and live for 3 to 4 weeks. Females lay groups of eggs just below the surface in grassy areas of sandy, well-drained soils. The larvae (grubs) spend the winter underground, move up in the soil to feed on grass roots and then pupate in the spring. A few weeks later, they emerge from the soil and disperse by flight. Male beetles are attracted to females and congregate on plants to mate and feed.

Crops Affected: grapes

Damage

Feeding damage is most obvious on the leaves, though the greatest impact can be on young clusters when adult beetles remove the developing berries.
Crops Affected: apples, cherries, peaches, pears, plums

Damage

Attacks all tree fruits, particularly peach and apple. Adults (only) feed on the surface of the fruit and leaves of deciduous fruits (B, C). The fruit may be partly peeled and gouged in irregular shallow patches, or nearly devoured. The leaves are skeletonized (B). Damage is more severe in sandy locations, often occurring especially at orchard edges in proximity to grassy areas.

Management

Feeding damage from adults is sporadic and transient during the summer. If needed, an insecticide can be applied when leaf damage or the insects feeding on foliage are noted in the trees; retreatment may be necessary as new adults arrive.

Similar Species

Japanese beetle (Popillia japonica Newman) adults are metallic green or greenish bronze in color, with reddish wing covers and several white spots near the tip of the abdomen and along the sides. Its larvae are also large, C-shaped grubs. Both Japanese beetle and rose chafer are relatives of green June beetle (Cotinus nitida), with whom Japanese beetle sometimes occurs in the adult stage. The two species can be distinguished by the differences in their size and coloration; also, unlike green June beetle, which can injure both green and ripening fruit, Japanese beetle prefers fruit that is close to ripe.