
Cranberry rootworm beetle (Rhabdopterus picipes) feeding damage on camellia foliage results in C-shaped holes.
Jim Baker, North Carolina State University, Bugwood.org Management
The Cranberry rootworm beetle (Rhabdopterus picipes) is one of several leaf-feeding beetles and weevils that consume the foliage of woody landscape plants in South Carolina. These nocturnal-feeding adult beetles are shiny, dark bronze-black, about 1/4-inch long, and 1/8-inch wide. These beetles are seldom noticed because they hide in the landscape mulch during daylight hours, and the foliar damage appears similar to that of hail damage. The adults feed on landscape plants for several weeks in the late spring and early summer. Their feeding results in curved, C-shaped, and elongated holes in leaves of azalea, rhododendron, camellia, blueberry, hollies, roses, redbud, oakleaf hydrangea, and other shrubs. After feeding, the female adults lay eggs on the soil. Upon hatching, young beetle larvae move into the soil to feed on the roots of the host plant. They feed throughout the summer until fall and then move deeper into the soil to over-winter. The larvae pupate within the soil during early spring, and the adults emerge in late spring to begin foliar feeding and repeat the one-year life cycle.
Cultural Controls: Keep landscape plants as healthy as possible to tolerate the damage. If there is inadequate rainfall, irrigate plants weekly during the growing season providing 1-inch of water per week.

Cranberry rootworm beetle (Rhabdopterus picipes) feeding on azalea foliage resulting in curved, elongate holes.
Chazz Hesselein, Alabama Cooperative Extension System, Bugwood.org
A soil analysis test is recommended to determine which nutrients are needed in the soil to improve plant growth and to determine if lime is required. In the absence of a soil test, fertilize plants with slow-release tree and shrub fertilizer, such as a 12-6-6, in early spring and again 6 weeks later at a rate of 1 pound per 100 sq ft. However, in the coastal counties of Beaufort, Charleston, and Horry, there is typically sufficient phosphorus that naturally occurs in the soil. Therefore, in these areas, use a 15-0-15 fertilizer around the shrubs during the spring. For proper nutrient management in landscape beds, have the soil tested the following fall or winter.
Although mulch provides a hiding place for adult beetles, it is quite beneficial to landscape plants in conserving soil moisture, regulating soil temperature, and suppressing weeds. Apply a 3- to 4-inch deep layer of mulch around woody shrubs.
Chemical Controls: Once flowering is over, shrub foliage should be sprayed with spinosad (a natural insecticide), bifenthrin, cyhalothrin, cyfluthrin, or permethrin as soon as feeding damage is detected. These are contact insecticides to control the adults feeding on the foliage. Also, spray to saturate the mulch or leaf litter beneath the shrubs, as during the daytime, the beetles hide in the mulch near the plants. To protect pollinating insects, do not spray during bloom. See Table 1 for examples of products labeled for foliar pest control on shrubs.
Alternatively, control can be obtained with soil drenches using a product containing imidacloprid. This a systemic insecticide that is taken up at the base of the shrub and moves upward into foliage and flowers. It may take one week for imidacloprid to translocate throughout smaller shrubs or up to a few weeks for larger shrubs. It is always best to apply imidacloprid after flowering to reduce the risk to pollinating insects. Be sure the plants are well-watered the day before application (to enhance insecticide uptake), then drench the soil around the base of the shrubs with a solution of imidacloprid. The amount of product to use is determined by the height of the shrub in feet, so follow the label directions for mixing with water. Systemic insecticide products generally protect shrub foliage for a year and are best applied in the spring. Because soil-applied insecticides, which are drenched around the base of the shrubs, do not move further outward into the root system, they will not kill the grubs feeding on roots nearby. See Table 1 for examples of products containing imidacloprid.
Table 1. Insecticides to Control Cranberry Rootworm Beetle on Shrubs
Insecticide Active Ingredient | Examples of Common Insecticide Products Labeled for Use on Landscape Ornamentals |
Bifenthrin | Hi-Yield Bug Blaster Bifenthrin 2.4 Ready to Spray
Hi-Yield Bug Blaster II Bifenthrin 2.4 Ready to Spray Monterey Mite & Insect Control Monterey Mosquito Control Martin’s FLEE Ready to Use Yard Spray Ortho Outdoor Insect Killer Concentrate Ortho Outdoor Insect Killer Ready to Spray Ortho Bug B Gon Insect Killer for Lawns & Gardens Ortho Bug B Gon Insect Killer for Lawns & Gardens1 Ortho BugClear Insect Killer for Lawns & Landscapes Bifen I/T Talstar P Professional Insecticide Up-Star Gold Insecticide Hi-Yield Vegetable & Ornamental Insect Control Granules Bonide Eight Insect Control Flower & Vegetable Above & Below Soil Insect Granules |
Imidacloprid | BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Insect Control Concentrate Landscape Formula
BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed Concentrate 2-1-1 BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed II Concentrate 2-1-1 BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed II Ready to Use Granules 2-1-1 BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed Ready to Use Granules 2-1-1 BioAdvanced Science-Based Solutions 2 in 1 Systemic Rose & Flower Care Ready-to-Use Granules II Bonide Annual Tree & Shrub Insect Control w/ Systemaxx Bonide Systemic Granules Insect Control Bonide Systemic Insect Spray w/ Systemaxx Ready to Spray Ferti-lome Tree & Shrub Drench Hi-Yield Systemic Insect Granules Hi-Yield Systemic Insect Spray Ready-to-Spray Martin’s Dominion Tree & Shrub Insecticide Concentrate Monterey Once A Year Insect Control II |
Cyfluthrin | BioAdvanced Science-Based Solutions 24 Hour Lawn Insect Killer Ready-to-Spray
BioAdvanced Science-Based Solutions Complete Brand Insect Killer for Soil & Turf Ready-to-Spray I BioAdvanced Science-Based Solutions Insect Killer for Lawns Ready-to-Spray BioAdvanced Science-Based Solutions Rose & Flower Insect Killer Ready-to-Use |
Cyhalothrin | Bonide Eight Insect Control Garden & Home II Ready to Use
Cutter Backyard Bug Control Spray Concentrate Cyzmic CS Controlled Release Insecticide Martin’s Cyonara Lawn & Garden Insect Control Martin’s Cyonara Lawn & Garden Insect Control Ready-to-Spray Spectracide Triazicide Insect Killer for Lawns & Landscapes |
Permethrin | Bonide Eight Insect Control Vegetable, Fruit, & Flower Concentrate
Bonide Eight Yard & Garden Ready to Spray Hi-Yield 38 Plus Turf, Termite & Ornamental Insect Control Hi-Yield Lawn Garden Pet & Farm Insect Control Southern Ag Permetrol Lawn & Garden Insecticide Tiger Brand Super 10 Brand |
Spinosad | Bonide Captain Jack’s Deadbug Brew Concentrate
Bonide Captain Jack’s Deadbug Brew Ready to Spray Bonide Captain Jack’s Deadbug Brew Ready to Use Bonide Colorado Potato Beetle Beater Concentrate Conserve SC Turf & Ornamental Monterey Garden Insect Spray Monterey Garden Insect Spray RTU Natural Guard by ferti-lome Spinosad Bagworm, Tent Caterpillar & Chewing Insect Control Natural Guard by ferti-lome Spinosad Soap Ortho Insect Killer Tree & Shrub Concentrate Southern Ag Conserve Naturalyte Insect Control |
1RTS = Ready to Spray (a hose-end sprayer) |
Pesticides are updated annually. Last updates were done on 8/24 by N. Jordan Franklin.
Originally published 02/18