Bombaci Tree Care, LLC
Independently Owned & Operated
Gypsy Moth Information
What
are Gypsy Moths?
What is the Lifecycle of a Gypsy Moth?
When are Trees Damaged?
What Types of Trees do Gypsy Moths Eat?
Signs of a Gypsy Moth Infestation
What are Gypsy Moths?
Gypsy Moths (Lymantria Dispar) are a type of insect that are native
to Asia and Europe and was brought to the United States in 1869 as
an experiment. Unfortunately, this “experiment” went terribly wrong
and the results have been devastating in some areas of the country,
most noticeably the Northeast.
The purpose of introducing these moths in 1869 was to help jump
start the silkworm industry. The idea was that they would be used to
breed with silkworms so that the silkworms would become hardier and
therefore produce more silk in the United States. The breeding was
unsuccessful and on top of this failure, the Gypsy Moth escaped and
started its first colony in Medford, Massachusetts.
What is
the Lifecycle of a Gypsy Moth?
There are four developmental stages in a Gypsy Moth lifecycle: the
egg, larva (caterpillar), pupa, and adult. Female Gypsy Moths lay
egg masses containing anywhere from 500 to 1,000 eggs in areas that
are sheltered from weather conditions, such as on the underside of
bark on trees. The eggs are protected with a thick layer of tan
colored “hair”. Each egg mass measures roughly an inch and a half
(1.5) in length and about three quarters (0.75) of an inch in width.
The egg stage is the overwintering stage of the lifecycle. Eggs can
be found attached to trees, house siding, and various other outdoor
surfaces. The eggs will hatch into caterpillars in April.
The larval (or caterpillar) stage is the one most people recognize.
These caterpillars are easy to spot because they have unique
physical characteristics not see on other types of leaf chewing
caterpillars. Each Gypsy Moth caterpillar has five pairs of blue
dots, immediately followed by six pairs of red dots along its back.
They are also covered in dark colored hairs. Very young caterpillars
may feed on leaves throughout the day, while older caterpillars feed
mostly at night. This means when there are large numbers of
caterpillars, feeding occurs both day and night. Younger
caterpillars find new feeding spots by crawling to the tops of
trees, where silken threads are spun and caught by wind currents.
Older caterpillars measure anywhere from 1.5 to 2 inches in length.
Gypsy moths caterpillars not make webs, therefore they are easily
distinguished from other forms of caterpillars, such as tent
caterpillars or webworms. The larval stage of the Gypsy moth lasts
for about seven weeks.
By June or early July, Gypsy Moth caterpillars begin their pupal
stage. During this time pupae are dark brown in color and have hard,
shell-like coverings. They measure about two inches long and are
covered with protective “hair”. The pupae can be found in areas that
are somewhat sheltered such as in leaf litter or crevices in the
bark of trees. Within ten to fourteen days, adult Gypsy moths emerge
and will remain from July through September.
Female Gypsy Moths are white to off white in color, have a tan
colored body, and a wingspan of about two inches. Female moths
cannot fly. The male moths are smaller than the females and have a
dark brown appearance, antennae that are feathery, and a wingspan of
about an inch and a half. Both the males and females are
recognizable by the inverted V shape that points toward a dot
located on the wings.
There is only one generation of Gypsy Moths produced each year.
Populations go through cycles where numbers increase for several
years straight, then go into a decline and then increase once more.
Outbreaks can happen in one area for a period of up to ten years;
however it is more common for high population numbers to remain for
two to three year stretches.
When
are Trees Damaged?
Tree damage occurs during the larval, or caterpillar, stage of the
lifecycle. This happens when the caterpillars emerge from their egg
masses and can last through mid-June or early July. The caterpillars
feed on the leaves of the trees, mostly during night time hours,
however very young caterpillars may feed during the day as well.
Caterpillars tend to seek shade from the sun during the day, but
feed can take place both day and night, especially during times of
heavy infestations.
Even though trees grow over a period of decades, they can be
destroyed in a matter of days. Gypsy moth caterpillar infestations
can completely defoliate a tree in as little as a few days to a
week.
The larvae (caterpillars) of Gypsy Moths grow by a process known as
moulting. There are six moults for females, and five moults for
males. Feeding takes place during the period between each moult,
known as the instar stage. With each moult, the appetite of the
caterpillar increases and feeding continues until the pupal state is
begun in mid-June or early July.
Depending on the level of infestation, the damage to trees can be
mild or extremely severe. While most deciduous trees can survive
mild and moderate defoliation, severe or complete defoliation can be
devastating to trees. Even mild to moderate defoliation, especially
if it is recurring, can weaken a tree and leave it vulnerable to
diseases and other insects.
What
Types of Trees Do Gypsy Moths Eat?
Gypsy Moth caterpillars are not terribly picky eaters, although they
do prefer the leaves of deciduous hardwood trees, like elm, maple,
and most especially oak. These caterpillars are also known to feed
on willow, apple, poplar, birch, and alder trees. As the
caterpillars continue to grow and spread, and infestations increase,
evergreen trees, such as spruces and pines, are also attacked. The
trees Gypsy Moth caterpillars seem to dislike include: tulips,
sycamores, black walnuts, ashes, balsams, dogwoods, and butternuts.
During periods of heavy infestations, the caterpillars have been
known to attack several types of shrubs as well.
Signs of a Gypsy Moth Infestation
Gypsy moth infestations are pretty easy to recognize. When the eggs
hatch in the spring, many fuzzy small caterpillars with two distinct
rows of spots down their backs can been seen. These caterpillars can
be found on trees, outdoor furniture, house siding, walkways,
driveways, cars, and many other areas outside. Once they make their
way up the bark of trees, they march up to the tree canopy and begin
munching on the leaves. In addition to seeing the actual
caterpillars, infestations can be identified by noting the
following:
- Egg masses on the trunks of trees, sides of houses, lumber or
tools kept outside, on swing sets, on outdoor furniture, and other
outdoor areas.
- Defoliation of trees and shrubs that has become noticeable.
- Holes in the leaves of trees and shrubs.
- Droppings (or frass) on cars, driveways, patios, picnic tables,
walkways, sidewalks, decks, roofs, swimming pools, etc.
During times of high infestation, Gypsy Moth caterpillars can
actually be heard due to their droppings (frass) falling through the
leaves of the trees to the ground. This sound is similar to the
sound of a light rain shower. To make matters worse, since Gypsy
Moths are not native to this area, there are very few natural
predators to keep their numbers down.
Not only are Gypsy Moth caterpillars annoying, harmful to trees and
shrubs, and a general nuisance, some people also suffer from eye or
skin allergies and rashes due to exposure to the caterpillars’
hairs.
For more information on our treatments for Gypsy Moths or to
arrange for a free estimate, please
contact us or use the free
estimate request link on this page.