June Beetle

family: scarabaeidae
species: phyllophaga spp.
common names: june beetle
hosts:
notes:

Agriculture and Agri-Food Canada Insect Identification Sheet No. 49 March 1981

June Beetle

Phyllophaga spp.

June beetles, found across Canada, are most destructive in Ontario and Quebec. In their larval stage (where they are known as white grubs) they attack potatoes, corn, strawberries and grasses, as well as transplants.

Injury:

The larvae attack garden seedlings and transplants by cutting the main stem or roots 2 to 5 cm below the soil surface, killing the plant. They burrow into tubers and soft roots producing large holes and tunnels up to 2 cm in diameter. Grass killed by larvae feeding on the roots can be rolled up like a carpet. Often the result of root damage to the plant is browning or dwarfing. Adult beetles feed on the leaves of many trees and shrubs.

Life History:

Adult june beetles are shiny, reddish-brown, and up to 2.5 cm in length. In June the females deposit their pearly-white eggs in balls of earth 5 to 10 cm deep in the soil. The young grubs emerge 2 to 3 weeks later. The first summer they feed mostly on decaying vegetation. The larvae are white, dark headed, with a double row of spines on the underside of the last body segment. In the fall they burrow down in the soil below the frost line to overwinter. It is in the second summer that the most serious damage occurs as the larvae return to near the soil surface to feed on host roots. In the fall they once more hibernate below the frost line. In the third year they feed until June, when they pupate in earthen cells. Adults emerge within a month, but remain in their cells over the winter. In the spring of the fourth year, the adults emerge from the ground to feed, mate and lay eggs. While the 3-year life cycle is the most common, a few species complete their life cycle in 1 year, while others may take up to 4 years.

Pest Management:

June beetles are usually kept in check by a number of parasites and predators. If infestation is severe, contact your provincial Department of Agriculture for control recommendations.