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Pest Watch:
European Chafer
WASHINGTON STATE UNIVERSITY EXTENSION FACT SHEET • FS078E
WSU Extension Pest Watch fact sheets identify new agricultural pests in or near Washington State that pose
environmental and economic threats. In the event of a severe pest outbre\
ak, a Pest Alert will be issued with emergency
pest management and control information.
Introduction
The European chafer (scientific name Rhizotrogus majalis,
family Scarabaeidae) is a beetle that causes damage to turf
and cereal crops when in its larval (or grub) form. Because
it is now confirmed as a problem in southwest British
Columbia, Canada, it is important that Washington State
gardeners and horticultural professionals are aware of this
pest, recognize its various life stages, and know how to
report new infestations.
Distribution
The European chafer was introduced to the United States
in the 1940s on the East Coast. States that are currently
infested with the pest include New York, Michigan, Ohio,
Maryland, West Virginia, and Indiana. In 2001, European
chafer grubs were discovered infesting lawns in New West -
minster, the greater Vancouver area of British Columbia,
Canada, less than 15 miles from the northernmost border
town in Washington State (Fig. 1). Canadian entomologists
have since then tracked a slow rate of natural dispersal up
to 10 miles from the epicenter.
The risk of movement from infested areas via human activ -
ity is high; fortunately border inspections of nursery plants
and turf allow for the chance to exclude the pest from
Washington State. When traveling to known infested areas,
be sure to check items purchased there such as nursery
plants. Follow inspection rules at the border and help pre -
vent this pest from expanding into Washington State.
Identification
Adult European chafers are brick-colored to light brown.
As with other scarab beetles, they have that typical oval,
June-beetle shape and are about 1/2 inch long (Fig. 2). The
larvae are C-shaped and white with a dark head capsule.
When mature, European chafer larvae have three pair of
visible legs and are about 3/4 inch long (Fig. 3).
Other insect larvae that feed on turf include crane flies and
cutworm caterpillars. Crane larvae are legless and tubular,
with a retracted head capsule (Fig. 4; see also EB0856, Euro -
pean Crane Fly: A Lawn Pasture Pest ). Cutworms, also pests to
garden plants, are typical caterpillars, not C-shaped, and have
prolegs (small fleshy protuberances) on the abdomen (Fig. 5).
Figure 1. Known distribution of European chafer in the
Pacific Northwest as of 2011.
This fact sheet is part of the WSU Extension Home Garden Series.
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Life Cycle
European chafers mate as darkness sets in and females seek
egg-laying sites in the soil soon after mating. Each female
lays 20–30 eggs. Larvae hatch from the eggs two weeks later
and begin to feed on plant roots. Chafers spend the winter
as larvae and pupate in May, emerging as adults 2–3 weeks
later in June.
Damage
Larvae are the damaging stage of the European chafer. They
commonly prefer to feed on cereal plants like turf grasses
and wheat. They have also been found feeding on the fine
roots of broadleaf plants and conifers. In turf, larvae feed
in the root zone up to the root crowns. Heavy infestations
cause browning and death of turf (Fig. 6), especially as
Figure 2. Adult European chafer.
Figure 3. Late larval instar of European chafer grub.
Figure 4. European crane fly larvae. The head is retracted
into the body and the prominent spiracles (breathing holes)
are at the tail end of the body.
Figure 5. Cutworm caterpillar ( Noctua pronuba ) commonly
found in the thatch layer of lawns. Note the prominent
head capsule and prolegs on the abdomen (E. Bechinski,
University of Idaho).
Figure 6. Lawn showing damage caused by European
chafer grubs feeding. The turf plants are gone and moss has
invaded the area.
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drier months begin. Secondary pests such as raccoons and
skunks peel back turf to feed on the grubs, causing signifi -
cant damage to lawns.
Management
Generally, 5–10 European chafer grubs per square foot
should warrant management tactics. If this pest spreads
into Washington State, an increase in pesticide usage on
home lawns will create pesticide run-off risks in urban
and residential areas. Insecticides should therefore be used
judiciously. Some parasitic nematodes such as Steinernema
scarabaei and Heterorhabditis bacteriophora appear to be
effective at reducing grub populations. Nematodes are
available to purchase at many home and garden supply
stores. Irrigation and mowing practices have also proved
effective in suppressing and sometimes masking chafer
problems in lawns. Frequent watering of lawns during
European chafer egg-laying periods (mid-June until August)
gave similar protection as some insecticides in experiments
in Michigan State ( Smitley et al. 2004 ). However, frequent
irrigation may not be practical in areas with costly water.
Monitoring
Monitoring for European chafer grubs is very similar to
that for crane fly (Fig. 7). April to May and September to
October are the best times to monitor for the grubs because
this is when they are the easiest to spot (i.e., at their largest
stage). You may see the adults from mid-June until August.
They swarm at dusk, sounding much like buzzing bees.
When large populations are present, the evening swarms
can be very obvious.
Look for areas of lawns that show symptoms of damage.
It is best to take samples along the edge of dead or dying
grass plants. Do not take a sample from the middle of dead
turf, as the insects may have left that area to feed on living
plant material. Pay especially close attention to areas that
might be suffering from predatory raccoon or skunk activ -
ity.
Using a spade or serrated knife, cut a 12-inch square 4–5
inches deep. Sift through the loose soil and thatch to look
for the C-shaped grubs. Repeat the sampling in at least
four locations to develop an average number of grubs per
sample (or per square foot). The threshold for European
chafer grubs is dependent on the health of the turf.
Bring samples to your local Extension office or the Wash -
ington State Department of Agriculture . Report sightings at
1-877-9-INFEST or PestProgram@agr.wa.gov .
Further Reading
Antonelli, A. and G. Stahnke. 1998. European Crane Fly:
A Lawn and Pasture Pest. Washington State University
Extension Publication EB0856, http://cru.cahe.wsu.edu/
CEPublications/eb0856/eb0856.html .
British Columbia Ministry of Agriculture. 2010. European
Chafer —A New Turf Pest. http://www.agf.gov.bc.ca/
cropprot/chafer.htm .
LaGasa, E.H., P. Hertzog, and D. Bowden. 2003. 2002 Light-
trap Detection Survey for European Chafer, Rhizotrogus
majalis (Raz.) (Coleoptera: Scarabeidae), a Turf and Grain
Pest Recently Found in B.C., Canada. Washington State
Department of Agriculture PUB 081, http://agr.wa.gov/
PlantsInsects/InsectPests/Exotics/Surveys/european_
chafer02.pdf.
Smitley, D.R., C. DiFonzo, K. Frank, S. Bughra, and T.
Fernandez. 2004. Addressing Widespread Damage
to Turf, Wheat, and Nursery Crops by the European
Chafer: Immediate Strategies and Long-Term Solutions.
Michigan State University, Project Number GR01-050.
http://www.ppdl.purdue.edu/PPDL/pubs/GR01-050.pdf .
Figure 7. European chafer grubs (in orange circles) exposed
during sampling of damaged turf.
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By Todd Murray , Extension Educator, WSU Skamania County Extension; Gwen Stahnke , Extension Turf Specialist, WSU Puyallup Research and Extension Center; and Eric LaGasa , Chief Entomologist, Washington State Department of Agriculture.
All images provided by Todd Murray, unless otherwise indicated.
Use pesticides with care. Apply them only to plants, animals, or sites as listed on the label. When mixing and applying pesticides, follow all label precautions to protect yourself and others around you. It is a violation\
of the law to disregard label directions. If pesticides are spilled on skin or clothing, remove clothing and wash skin thoroughly. Store pesticides in their original containers and keep them out of the\
reach of children, pets, and livestock.
Copyright 2012 Washington State University
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Issued by Washington State University Extension and the U.S. Department of Agriculture in furtherance of the Acts of May 8 and June 30, 1914. Extension programs and policies are consistent with federal and state laws and reg\
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ce. Trade names have been used to simplify information; no endorsement is intended. Published November 2012.
FS078E
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