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E-M:/ Definitive Michigan Asian Lady Beetle Infestation Guide

Enviro-Mich message from "Alex J. Sagady & Associates" <ajs@sagady.com>

Forwarded bounced message....from MSU Extension

Date: Tue, 23 Oct 2001 12:12:48 -0400
To: enviro-mich@great-lakes.net
From: Darren Bagley <bagleyd@msue.msu.edu>
Subject: Myths and Facts on Ladybird Beetles
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Hopefully this will clear up the information and misinformation on
ladybird beetles (aka ladybugs).  I have provided university references
for the answers to the many questions.

1.  Is there a superabundance of ladybird beetles in 2001? <italic>There
were extremely large populations produced in 2000/2001 all across the
Great Lakes Region.  (from Tom Ellis; MSU Entomologist)


2.  Why are there so many?  <italic>There was an enormous population
explosion of the ladybugs principal prey, the aphid.  The reason for this
was because weather conditions were perfect for aphid reproduction and
survival during the summer of 2000. So, lots of food for the Asian
ladybug produced tremendous number of ladybugs by summers end.   (from
Tom Ellis; MSU Entomologist)


3.  Do they have spots?  What color are they?  <italic>Color variants
found in the United States are different shades of yellow, orange, or
red, either with or without black spots on the wing covers. Some have 19
black spots while others have faded spots that vary in number and size. A
good web site for identification (with color pictures) is at


4.  Where did they come from? Were they intentionally released?  By who?
<italic>The multicolored Asian lady beetle (Harmonia axyridis) is native
to Asia but occurs in many areas of the United States. This beneficial
insect was imported and released as early as 1916 in attempts to
naturally control certain insect pests. But the first populations were
not found in this country until 1988 in Louisiana near the busy port of
New Orleans. Over the years, federal, state and private entomologists
released the insect at a number of locations. But it was not detected in
these places until some years after it had became established in
Louisiana. In addition, accidental entries have occurred via imported
nursery items at ports in Delaware and South Carolina. Thus, it is
uncertain whether the beetle's establishment resulted from planned
releases, accidental entries or both.  from


5.  Do they bite people and/or livestock? <italic> The Asian ladybug
might take a nip out of your finger if handled. If you

get nipped, clean and treat bite with an antibiotic as a precaution
against a secondary infection. There have been a couple of cases of
allergies linked to Asian ladybugs. The patients experienced itchy eyes,
sneezing, congestion and a runny nose.  from Tom Ellis, MSU entomologist
  Although an uncommon occurrence, multicolored Asian lady beetles have
been reported to nibble, nip, or "bite" humans. These lady beetles are
not aggressive toward humans, and they simply may be examining an
unfamiliar substrate or they may be seeking moisture. Their occasional
nibbling is not reported to break the skin or draw human blood.


6.  Do they eat plants and/or fruit?  <italic>Yes, this has been
documented.  It is unclear whether they are damaging the fruit directly,
or simply taking advantages of wounds already in the fruit.  For more
information, see the MSU Fruit CAT Alert at


7.  Do they have natural predators/parasites? Do they taste bad?
<italic>If agitated or squashed, the beetles may exhibit a defensive
reaction known as "reflex bleeding," in which a yellow fluid with an
unpleasant odor is released from leg joints. This reaction generally
prevents predators, such a birds, from eating lady beetles. from
http://www.ars.usda.gov/is/pr/2000/001030.beetlefacts.htm  In 1993, North
Carolina Department of Agriculture researchers documented substantial
levels of parasitism (14.2%) of the multicolored Asian lady beetle by a
tachinid fly. However, parasitism levels subsequently dropped to an
average of 2 to 4% from 1994 through 1999 in North Carolina (C.A. Nalepa
& K.A. Kidd, personal communication), suggesting that this parasitoid
does not cause significant mortality of multicolored Asian lady beetles.
from http://ohioline.osu.edu/hse-fact/1030.html


8.  What harm, if any, do they do to the environment?  <italic>Hence,
there is some controversy regarding the origins of this nonnative
species. Nonetheless, the multicolored Asian lady beetle is now well
established in the United States, where it currently thrives in many
parts of the Midwest, East, South, and Northwest. This nonnative species
appears to be displacing some of our native lady beetles in Ohio.


9.  Are they crossbreeding with native ladybird beetles?  <italic>I have
not found any references to that in the literature


10.  What do the native ones look like?  <italic>There are some pictures
of native ladybird beetles at Iowa State University at


11.  Does any survey keep track of insect populations in the state?
<italic>I do not know of a statewide survey of all insects.  Michigan
State University Extension is collecting data on the nuisance ladybird
beetle calls they are receiving this year in the county MSUE offices.
The MSU Extension CAT alert system also keeps track of pests that may
potentially damage agriculture and/or the green industry. You can view
CAT alerts at http://www.msue.msu.edu/ipm/aboutcat.htm. The Michigan
Natural Features Inventory keeps track of threatened and endangered
species.  You can visit them at


12.  Do they harm clothing or structures?  <italic>An orange liquid is
expelled when Asian ladybugs are crushed.  This fluid can stain some
surfaces and fabrics.  From Tom Ellis, MSU Entomologist  Lady beetles are
not structure-damaging pests, unlike insects such as termites and
carpenter ants. Lady beetles do not chew or bore holes in walls or eat
carpet or furniture. They do not lay their eggs in homes.  from


Darren Bagley, Natural Resource Agent

MSU Extension-Genesee County

G-4215 W. Pasadena

Flint, MI 48504-2376


tel: (810) 244-8524  fax: (810) 732-1400

web site:  http://www.msue.msu.edu/genesee/natres

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Alex J. Sagady & Associates  http://my.voyager.net/~ajs/sagady.pdf

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