Master
Gardeners are a first line of defense for detecting new pests in our area.
Your fellow B.C. Master Gardener found white grubs infesting a New Westminster
lawn last November 2001. This was reported in their newsletter, alerting
Al McHenry to pass this information on to the Washington State Department
of Agriculture. Now the WSDA is combing Whatcom County for signs of European
Chafer. We might not have it yet, but it is a definite threat to Whatcom
County lawns and agricultural crops. So, “good job” to the Master
Gardeners that brought this pest to the forefront. The sooner that we
detect this pest, the better we can manage it.
The European chafer was introduced to the US in the 1920’s on the
East Coast. States that are currently infested with European Chafer include
the North Eastern US extending to Michigan State. As in Europe, this pest
is a serious problem in turf and cereal crops in the U.S.
Description and History Life: The adults of the European Chafer
are small, brick colored brown to light brown/tan beetles. They have that
typical oval, June beetle shape and are about 1/2 inch long. Adult beetles
emerge in mid-June and will be present through July and possibly August
in our area. During the evening, the beetles swarm at dusk. These “swarms”
can be rather noisy, sounding much like buzzing bees. Beetles mate as
darkness sets in and females will seek ovipositional sites in the soil
soon after mating. Eggs are laid singly inside earthen cells. A female
will lay 20-30 eggs. Larvae will hatch from the eggs two weeks later and
begin to feed on plant roots. The larvae are “C”-shaped, about
¾ inch long when mature, white with a dark head capsule. They appear
much like root weevil larvae but scarabs have three pair of visible legs
and grow larger. Chafers spend the winter as larvae and will pupate in
May, emerging as adults 2-3 weeks later in June.
Damage
and Management: Larvae are the damaging stage of this pest. Generally,
European chafers prefer to feed on cereal plants like turf and wheat.
Larvae can feed on just about anything and have been found damaging the
fine roots of broadleaf plants and conifers. In turf, larvae feed in the
root zone up to the root crowns of turf grass. Heavy infestations cause
browning and death of turf, especially as drier months begin. Secondary
pests, such as raccoons and skunks will peel back turf to feed on the
grubs causing significant damage to lawns. Check out BC Ministries of
Agriculture’s web site to see extensive damage caused by skunks:
http://www.agf.gov.bc.ca/croplive/cropprot/chafer.htm
Monitoring for white grubs is very similar to that for crane fly. Visit
http://whatcom.wsu.edu/cranefly to see how to monitor. The threshold for
white grubs is dependant on the health of the turf. Generally, 5 to 10
grubs per square foot should warrant management tactics. Monitoring adult
flight should be fairly obvious because of their swarming behavior and
the noise they make.
Managing
the European Chafer will not be easy. Reports across the country have
alluded that this pest tolerates many of our insecticides. The current
insecticides that are recommended are very unsavory (if you are a bird
or pollinator). If or when we have to look for management practices, you
can expect that there will be quite a bit of research involved to find
good alternative strategies.
Keep your eye’s peeled Master Gardeners. Inspect areas of turf that
look marginal, much like you do for crane flies. Pay especially close
attention to areas that might be suffering from raccoon or skunk activity.
There aren’t many grub-like insects in your lawn so if you run across
any beetles or grubs, please collect them. You can bring them into the
Cooperative Extension office and we will pass them on to Washington State
Department of Agriculture.
Master
Gardeners are a first line of defense for detecting new pests in our area.
Your fellow B.C. Master Gardener found white grubs infesting a New Westminster
lawn last November 2001. This was reported in their newsletter, alerting
Al McHenry to pass this information on to the Washington State Department
of Agriculture. Now the WSDA is combing Whatcom County for signs of European
Chafer. We might not have it yet, but it is a definite threat to Whatcom
County lawns and agricultural crops. So, “good job” to the Master
Gardeners that brought this pest to the forefront. The sooner that we
detect this pest, the better we can manage it.
Damage
and Management: Larvae are the damaging stage of this pest. Generally,
European chafers prefer to feed on cereal plants like turf and wheat.
Larvae can feed on just about anything and have been found damaging the
fine roots of broadleaf plants and conifers. In turf, larvae feed in the
root zone up to the root crowns of turf grass. Heavy infestations cause
browning and death of turf, especially as drier months begin. Secondary
pests, such as raccoons and skunks will peel back turf to feed on the
grubs causing significant damage to lawns. Check out BC Ministries of
Agriculture’s web site to see extensive damage caused by skunks:
http://www.agf.gov.bc.ca/croplive/cropprot/chafer.htm
Managing
the European Chafer will not be easy. Reports across the country have
alluded that this pest tolerates many of our insecticides. The current
insecticides that are recommended are very unsavory (if you are a bird
or pollinator). If or when we have to look for management practices, you
can expect that there will be quite a bit of research involved to find
good alternative strategies.