Pest Profile

Photo credit: Ted Kropiewnicki, BugGuide.net

Common Name: Northern masked chafer

Scientific Name: borealis

Order and Family: Coleoptera,

Size and Appearance:

Adult Egg /Nymph Pupae (if applicable)

Length (mm) 11-14 mm 1.7 mm 4.5 mm at eclosion and 17 mm 22-25 mm as mature 3rd instars Appearance 6-7 mm 1.2 mm wide, Dirty white, soft bodied, 8 mm wide, first wide, brown pearly white, and robust with a brown creamy white oval head and six well- and turn to developed legs reddish brown before adults emerge

Type of feeder (Chewing, sucking, etc.): Chewing

Host plant/s: Kentucky bluegrass and perennial ryegrass. This is native to North America, and specimens have been collected from Maine to California and as far south as Alabama.

Description of Damage (larvae and adults): Young larvae burrow to the soil surface in search of plant roots, they also eat general organic material in the soil as well as thatch. The larvae grow rapidly when adequate moisture and food are present. They can develop to second instars in 20 to 24 days at 80°F and third instars are common by September. This is when most of the damage occurs. As the soil temperatures begin to drop in the fall, the larvae begin to dig downwards to hibernate. Larvae may dig down 12 inches but most are within 3 to 6 inches, at least in southern states. Grubs surviving the winter return to the upper level of soil in late April and May to feed. The larvae again move down slightly in late May and early June to pupate.

Turf begins to show drought stress in late summer into fall or spring and does not rapidly recover after rain or irrigation. Heavy infestations result in turf dying in irregular patches. Grubs destroy grass roots, causing the affected area to become spongy, which allows the sod to be rolled back like a piece of carpet. Birds, skunks, raccoons and opossums commonly dig up turf around the dead patches. Moles may tunnel extensively where grub populations are high. Infested turf feels spongy under foot and is easily lifted because of the absence of roots. The adults do not feed on ornamental plants or turf.

References: Cranshaw, W. (2004). Chapter Ten: Clearwing Borers: Peachtree (or Crown) Borer. In Garden of North America: The ultimate guide to backyard bugs. (p. 524). Princeton, NJ: Princeton University Press.

White Grubs in Home Lawns. Penn State College of Agricultural Sciences Department of Entomology Advice from Extension, 2016. Retrieved April 2, 2016 from http://ento.psu.edu/extension/factsheets/white-grubs-lawns

Masked Chafers. University of California Agriculture and Natural Resources Integrated Pest Management Program, 2014. Retrieved April 2, 2016 from http://www.ipm.ucdavis.edu/TOOLS/TURF/PESTS/inchaf.html

Northern Masked Chafer. California Academy of Sciences, iNaturalist.org. Retrieved April 2, 2016 from http://www.inaturalist.org/taxa/301437-Cyclocephala-borealis

Northern Masked Chafer. Bugguide.net. Retrieved April 2, 2016 from http://bugguide.net/node/view/373090/bgimage