The Gypsy Moth, one of the most damaging forest pests,
continues to be a problem in Michigan. While infestation
density fluctuates from year to year, Bloomfield Township is
committed to controlling Gypsy Moth damage in our
- Native to Europe, Asia and North Africa
- Moths are only seen in mid-summer
- Males moths are grayish-brown and can fly, females
are larger, white with black marks and cannot fly
- Caterpillars have a yellow stripe on the back with
blue and red dots
The Gypsy Moth is in the same category of insects as moths
and butterflies. This group of insects is known for both their
beauty and their destructive nature. The four life stages of
the Gypsy Moth and the time of appearance include:
– August to April
Most of the yearly cycle of the Gypsy Moth is spent in the
egg stage. The egg masses survive the winter insulated by the
covering of hair. The egg stage in Michigan usually runs from
August to April. The egg mass in late summer and early fall
appears to be a dark tan to light brown turning light tan to
gray in color. An individual egg mass may contain anywhere
from 100 to 1,200 eggs. The egg masses will lie on tree bark
and on many natural and manmade objects that are commonly
Larvae (Caterpillar) – Early May into July
of the larvae is influenced by spring warming trends with most
eggs hatching within a week. Larvae are approximately 1/8 inch
at hatching and grow to about 2 to 3 inches long before
As the larvae move up the tree, a thin line of silk is
produced behind them. When the wind picks up the thread the
young larvae are moved to another location. When resting, the
young larvae can be found on the underside of the leaf along
the mid-rib of a leaf.
July and Early August
The larvae reach maturity between mid-June and early July
and then they enter the pupal stage. This is the stage during
which larvae change into adults or moths. Pupation lasts from
7 to 14 days. When population numbers are sparse, pupation can
take place under flaps of bark, in crevices, under branches,
on the ground, and in other places where larvae rest.
Moth – Mid July to Early August
The adult Gypsy Moth emerges from the pupal shell and
contains mature eggs or sperm so mating can occur immediately.
The adult form does not feed and usually lives only about a
Gypsy Moth in the United States
The Gypsy Moth is native to Europe, Asia and North Africa.
In 1869 a scientist in Medford, Massachusetts, introduced the
European strain of the gypsy moth into the United States. He
wanted to breed them with other moths and develop a new strain
of silk-producing caterpillars. The experiment failed and some
of the caterpillars escaped, finding this new country to their
liking because of its adequate food supply and few natural
Since then, Gypsy Moths have spread through the
northeastern states, North Carolina, Washington and California
affecting over 19 states. Gypsy Moth defoliates millions of acres of
woodlands each year.
A mobile society helps to spread the moths via logs,
pulpwood and wood chips, nursery stock, mobile homes, and
outdoor household articles. Federal regulations prohibit
the movement of such articles from the quarantined areas into
or through areas outside of the quarantine. Further
information concerning the articles requiring inspection and
certification prior to movement can be found
at this website.
Gypsy Moth in Michigan
Gypsy Moth is an episodic organism that can exist at low
populations. Low populations increase and become high
populations, which crash and the episode begins over. Since
the mid 1950’s Michigan has battled the Gypsy Moths. Major
defoliation events have taken place since the mid 1980’s.
Significant Gypsy Moth population and defoliation first
occurred in the Clare-Midland area and moved up the central
portion of the Lower Peninsula. In the early 1990’s
populations moved east, west and then south in Michigan into
the Grand Rapids and Flint areas. By the mid-1990’s
populations began popping up in the metropolitan Detroit area.
As new infestations were discovered, regulatory policy
shifted from trying to eradicate the gypsy moth to a policy of
containment in the late 1970s. Today, Gypsy Moth can be found
throughout all of Michigan including the Upper Peninsula.
Bloomfield Township’s Gypsy Moth Management Program
The Township has assumed primary responsibility for Gypsy
Moth management. Since 1993 Bloomfield Township, together with
the National Gypsy Moth Management Group, has implemented an
integrated pest management approach to reduce and contain the
Gypsy Moth problem. The goal is to control the pest and
minimize the economic, social and environmental costs.
Components of the program include: public education, intensive
biological monitoring and treatment plus evaluation.
Annually, National Gypsy Moth Management Group personnel
collect data from biological surveys. Such surveys are
conducted at permanently established survey locations to
determine Gypsy Moth population, density and health,
susceptibility and vulnerability of trees and infestation
trends. This yellow tag is placed on trees that grow within
the survey areas.
The fungus, E maimaiga (a biological organism), has
been cited as the key factor in the reduction of Gypsy Moth
populations. Personnel from the Management Group apply the
fungus to targeted trees in sites around the Township in the
spring. If determined necessary another control measure, of
selective ground spray application of Bacillus
thuringiensis (Bt is a naturally occurring bacterium) by a
private firm is combined with inoculation of the fungus.
Concerns of residents are addressed through the season. A
final report from the company is submitted in the winter for
review and determination of future actions. The report
outlines the program’s effectiveness including such issues as
treatment timing, control measures and identification of
FREQUENTLY ASKED QUESTIONS
I’m not sure if it’s a Gypsy Moth, how can I tell?
It’s not a Gypsy Moth is if builds a cottony nest or
web in trees; looks like a white moth that flies; is larger
than a 50-cent piece or colorful; is a caterpillar with long
stripes on its back or sides; or flies in springtime.
What do Gypsy Moths eat?
The Gypsy Moth is in the same category of insects as moths
and butterflies that feeds on tree foliage. While oak tree
leaves are the favorite food of a Gypsy Moth, they will feed
on more than 600 species of trees, shrubs and vines. Michigan
abounds with susceptible trees, including oak, birch, willow,
crabapple, maple, aspen, basswood, linden and tamarack.
What is Bt?
It stands for Bacillus thuringiensis, a bacterium
that occurs naturally in the soil and is known to be fatal to
Gypsy Moth. A commercial preparation is used to reduce Gypsy
Moth populations. Bt kills caterpillars, but it is not
harmful to humans, fish, wild animals or plants.
What can I do to help my trees against Gypsy Moth
The best action to be taken is to keep your trees well
watered, particularly during dry periods in the summer.
Avoid wounding your trees with lawn mowers or other
equipment. Avoid compacting the soil or damaging the root
system of trees. Fertilize when appropriate. Sanitize by
removing dead branches and stumps. When choosing new trees
for the yard, aim for a diversity of plants.
What should I do if I suspect Gypsy Moth presence around
If you suspect the presence of a Gypsy Moth, report
problems to: Bloomfield Township Engineering & Environmental
Services at 248.594.2800 or
click here to report
an environmental concern.
For More Information
Please contact the
Bloomfield Township Engineering and Environmental Services
Department if you have questions about the material
presented here. Please visit the following websites for more
information on Gypsy Moths:
State of Michigan – Department of Agriculture
USDA Animal and
Plant Health Inspection Service (APHIS)
Bloomfield Township Gypsy Moth Report
Some images provided by: Perdue University,
USDA Forest Service,
US Dept. of Agriculture - Forest and
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