WSU Extension


Caption: Thumbnail - leaf symptoms, large image - adult beetle
Photo by: T. Murray, WSU
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Raspberry : Raspberry beetle (raspberry fruitworm)
(revision date: 4/11/2018)

Raspberry fruitworm (the larva) and raspberry beetle (the adult) are pests of raspberries and loganberries. The adults are yellow-brown beetles about 1/6 of an inch long. Raspberry beetles overwinter in the ground as adults, emerging from the soil in the spring (typically April-May). Adults feed on developing leaves, flower buds, and flowers. They leave characteristic slits between the veins of unfolding leaves as they feed. Injured blossoms often develop into distorted or malformed berries. Eggs are laid on flowers, buds, or stems. Hatching larvae burrow into the center of developing fruits, feeding in the receptacle (core) and drupelets for a month or more. The larvae are white with brown patches on the back of each body segment. At maturity, they are about 1/3 inch long. After the larvae finish feeding, they drop to the ground where they burrow into the top 3 inches of soil and pupate. If the fruit is harvested before the larvae drop, they remain in the fruit and are a significant contaminant of harvested fruit. There is typically one generation per year. Raspberry beetle also feeds and reproduces on wild blackberries, thimbleberries, and salmonberries.
Management Options

Non-Chemical Management
  • Handpick and destroy adult beetles when practical. Adults are most active in early evening.
  • Since adult raspberry beetles tend to drop from the plants when disturbed, they can also be caught by placing a beating tray under the plant and tapping or shaking the canes vigorously (being careful not to damage canes). The tray can be as simple as an old umbrella or cookie sheet, or a frame with a piece of light-colored fabric attached. Adults will drop onto the frame and can be captured. For best results, beat in the morning or evening when the air is cool.
  • Maintain good weed control in and around plantings, particularly wild brambles that serve as alternate hosts.
  • Cultivating around plants in late summer to early fall may kill larvae and pupae and reduce the number of adults emerging in the spring.
Select non-chemical management options as your first choice!

Chemical Management

Monitor by scouting for the presence of adult beetles before flowers open. The best time to control this pest is prior to bloom. Larvae inside the fruit are not affected by chemical controls, so management must occur before they enter the fruit. Apply chemicals before eggs are deposited, when buds begin to swell and separate, and again just before blossoms open.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Captain Jack's Deadbug Brew RTSpray [Organic]
    Active ingredient: spinosad  |  EPA reg no: 4-471
  • Bug Buster-O [Organic]
    Active ingredient: pyrethrins  |  EPA reg no: 1021-1771-54705
  • Bull's-Eye Bioinsecticide
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-56872
  • ferti-lome Borer, Bagworm, Tent Caterpillar & Leafminer Spray
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-7401
  • This list may not include all products registered for this use.
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Caption: Thumbnail - leaf symptoms, large image - adult beetle
Photo by: T. Murray, WSU
Photo by: T. Murray, WSU
Photo by: T. Murray, WSU