Japanese beetle (L), green june beetle (R). (Credit: A. Gutierrez)
Originally posted August 26, 2016; edited July 10, 2018
Have you seen big green beetles in your California yard or garden? Or beetles feeding on your roses or other plants? There are many kinds of beetles commonly found in our landscapes, but the Japanese beetle is not one of them.
Many people think they've seen the Japanese beetle, a small scarab beetle with metallic green wings with white spots on the margins. However, Japanese beetles are generally not found in California.
The Japanese beetle is an exotic and potentially invasive pest for which the California Department of Food and Agriculture (CDFA) is conducting eradication efforts to limit its spread outside the current trapping and treatment area. For more information about Japanese beetles and CDFA's actions, see https://www.cdfa.ca.gov/plant/pdep/target_pest_disease_profiles/japanese_beetle_profile.html.
Japanese beetle (Credit: D. Cappaert, Bugwood.org)
Green Fruit Beetles
Green fruit beetles are large beetles commonly found during spring and summer in California. While green fruit beetles are much larger than Japanese beetles and have different markings, these two beetles are frequently mistaken for each other. Adult green fruit beetles feed on ripe and overripe stone fruits, but damage is typically negligible so no control is necessary.
Green fruit beetle larvae are large cream-colored grubs that live in compost piles and other soils with high organic matter. Find out more about green fruit beetles at http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/PESTS/grfruitbeetle.html.
Green June beetle. (Credit: Jack Kelly Clark)
Hoplia beetles are small, reddish-brown oval beetles that feed primarily on roses. They occur between March and May in California and tend to prefer feeding on light colored rose petals. For more information about hoplia beetles, see the Pest Notes: Hoplia Beetles.
Masked chafer adults are golden brown beetles, 3/4 inch long with dark brown heads. Larvae are white, C-shaped grubs with dark stripes on their backs and brown head capsules and legs.
Hoplia beetle. (Credit: Jack Kelly Clark)
Masked chafer grubs feed on the roots of turfgrass. Damage appears in late summer or fall as irregular patches of brown, dying grass.
When full grown, white grubs are about 1-inch-long, much bigger than some other lawn beetles. Read more about masked chafers and other lawn pests at http://ipm.ucanr.edu/PMG/PESTNOTES/pn7476.html
Be a Part of the Solution
Other states in the U.S. have the invasive Japanese beetles and have implemented damage and control measures. It's important that we keep Japanese beetles and other invasive pests out of California. You can help by not moving plant material between states. Invasive pests and their potential damage can have devastating effects on California's natural environments, agricultural production, structures, gardens and ornamental plants. Learn more about invasive pests on UC IPM's Exotic and Invasive Pests page.
Masked chafer beetle. (Credit: Jack Kelly Clark)