Beetle Mania - A Quick Guide to Some Big Beetles

June beetles, European chafers, rose chafers and Japanese beetles belong to a group of beetles known as Scarab beetles. These beetles often cause highly-visible feeding damage to plant foliage and fruit. Some species are also very damaging in the larval stage. Typically known as white grubs, larvae feeding in the ground can cause serious economic damage to roots of many agricultural crops and/or turf.

Accurate identification of these pests is important in order to target effective control options. Here are some identification basics for scarab beetle pests commonly seen in Ontario.

June beetle (several species)

Adult: 15-50 mm, dark reddish brown; active late May and early June to mid-August

Image of June beetle

Hosts: Adults may feed on foliage of aspen, chestnut, elm, maple, oak, poplar, willow, various shrubs, roses and raspberries

Generations: 3-year life cycle

Larvae at white grub stage (C-shaped): Larvae are in soil for three years and feed all through the growing season. Larvae grow to 40 mm in length.

Close up of raster: How to ID: Look for two parallel rows of stout spines on the raster (last body segment) and a y-shaped anal slit.

Image of June beetle raster

European Chafer

Adult: 13 mm light brown; active mid-June to mid-August but variable.

Image of European chafers

Hosts: Adults feed very little - not a pest stage.

Generations: 1 generation /year

Larvae at white grub stage (C-shaped): Larvae feed on plant roots in late summer and early spring. Larvae grow to 15 mm in length.

Close up of raster: How to ID: Look for two nearly parallel rows of spines on the raster (last body segment) and a y-shaped anal slit.

Image of European chafer raster

Rose Chafer

Adult: 12 mm, light tan, slender; active mid-June.

Image of rose chafer

Hosts: Adults are a pest on pest on many different types of flowers, fruits, trees and shrubs. Skeletonizes leaves.

Generations: 1 generation/year

Larvae at white grub stage (C-shaped): Rarely observed, larvae feed on plant roots in summer and early spring. Larvae grow up to 18 mm in length.

Close up of raster: Image not available

Japanese beetle

Adult: 12 mm metallic green head, bronze wing covers, white tufts on abdomen; active late June to September.

Image of Japanese beetles

Hosts: Adults feed on more than 300 species of plants, but foliage / foliage of apples, cherries, grapes, linden, maples, peaches and roses. Skeletonizes leaves.

Generations: 1 generation/year

Larvae at white grub stage (C-shaped): Larvae feed on plant roots in late summer and early spring. Larvae grow to 12.5 mm in length.

Close up of raster: How to ID: Larvae have two short rows of stout spines in a v-pattern on the raster and a crescent shaped anal opening.

Image of Japanese beetle raster


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: Pam Fisher - Berry Crop Specialist/OMAFRA
Creation Date: 01 June 2007
Last Reviewed: 01 June 2016