The rose chafer is a type of scarab beetle whose adults feed on ornamental trees and shrubs in a manner that is similar to the Japanese beetle (Popillia japonica). Adult rose chafers are also highly attracted to flowers, such as those of rose and peony. Adult beetles are tan in color with reddish heads and long, spiny, reddish legs; wings do not entirely cover the abdomen. Females may be slightly larger than males. Adult rose chafers are typically active earlier in the season than Japanese beetle adults. The immature life stage (the larvae) overwinters. Larvae are also referred to as grubs, which will pupate by the early spring with adults emerging from the soil by June. Pupae are light yellow-brown in color and occur in the soil. Adults live for approximately 30 days and females lay their oval, shiny, and tiny eggs primarily in grassy areas, as deep as 6 inches in the soil. Eggs may be laid individually, in groups of 6-40. Eggs hatch, and tiny larvae begin to feed on the roots of grasses and weeds. Fully grown grubs are approximately 0.7 inches long. Successful development of this insect can only occur in light, sandy soils which helps limit their distribution and potential impact. The rose chafer occurs in New England, Colorado, and parts of eastern Canada.
Adult beetles skeletonize foliage of trees and shrubs and can also damage flowers on hosts such as rose and peony. It is considered a minor pest of roses and may have been more prevalent in the past. Adult beetles skeletonize or "chafe" the upper surfaces of their host plant leaves. Adult beetles feed during the day. Grape leaves may be preferred by this insect. Plants located on sandy sites may be preferentially attacked by this insect.
Scientific studies have identified effective lures that can be used to attract rose chafer adult beetles. One such study found that a mixture of valeric acid, hexanoic acid, octyl butyrate, trans-2-nonenol, and alpha-ionone out performed all other lure combinations included in the study (Williams et al., 2000). Mass trapping of rose chafers in vineyards may help reduce their populations over time locally. Traps are typically hung 1 meter off the ground, with light colored traps (pink, yellow, white) seemingly more preferred by the adult rose chafers.
Rose flowers may be protected by covering them with a fine netting (such as cheesecloth) during the height of the adult flight period of the rose chafer. Adult beetles can also be hand picked from host plants and dropped into a can of soapy water. In areas where this insect is a persistent problem, plowing or tilling any nearby suitable habitat of the larvae or pupae may help reduce their population, as the pupae can be very sensitive to disturbance (McCleod and Williams, 1990).
Birds may be killed if they eat adult rose chafer beetles, and as such they are not successful predators. Adult rose chafer beetles contain a toxin (cantharidin) that affects the proper functioning of the heart in small vertebrates. Chickens and ducks should not be allowed to feed on these beetles. This insect has few known natural enemies, and is well protected from predators in the adult life stage.
Acetamiprid (L)
Azadirachtin (NL)
Beauveria bassiana (NL)
Carbaryl (L)
Chlorpyrifos (N)
Cyantraniliprole (NL)
Flonicamid+cyclaniliprole (N)
Isaria (paecilomyces) fumosoroseus (NL)
Lambda-cyhalothrin (L)
Malathion (L)
Neem oil (NL)
Permethrin (L)
Tau-fluvalinate (NL)
Contact insecticides may need to thoroughly wet host plant foliage in order to be effective. Do not treat plants in bloom.
Active ingredients that may be applied systemically include: azadirachtin (injection, soil drench), cyantraniliprole (soil drench, soil injection), and neem oil (soil drench).
When used in a nursery setting, chlorpyrifos is for quarantine use only.
Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.
Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.
