Photo Stories
(May
17, 2004) The
U.S. Environmental Protection Agency, in a rare break from its message
that pesticides can be used safely for almost any pest management situation
regardless of whether they are necessary, effective or if there is a less
toxic way, is doing what many advocate it should do in more situations,
advising
the public with the message: "Don't use pesticides"
and "Don't panic." The cicadas are here, expected in 15 states!!!
But don't panic since they don't harm people or property. The cicadas
will show up in high numbers throughout eastern states and the Midwest
(Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North
Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia
and West Virginia).
Although you've probably heard them sing from high up in the trees during
the summer, you may not have seen a 17-year cicada brood. Most are familiar
with the cricket-like chorus that accompanies the humidity and thunderstorms
that East Coast summers bring. This May through June, however, some areas
of the country can expect an onslaught of millions of cicadas. That's
right, millions. Several species-called periodical cicadas-have much longer
life-cycles (13 or 17 years, for example) than the ones that typically
come each summer, called annual cicadas. One of the species that will
arrive in trees this spring has spent a remarkable 17 years maturing underground.
What is a cicada?
The cicada is a flying insect that can reach 1 to 1 and ½ inches
long. After spending most of its life as a nymph underground, during the
spring of the 13th or 17th year, depending on the species, the periodical
cicada emerges from the ground via exit tunnels and finds a nearby tree
or shrub on which to complete its maturation into adulthood (many individuals
have been known to exit on the same night). Once the cicada molts, its
soft body quickly hardens into an exoskeleton and the wings develop. After
a short maturation period, the adult male will gather with other male
cicadas and emit an unmistakable and loud song to attract female cicadas.
After mating, female cicadas will lay their eggs in a slit they make near
ends of small tree branches before dying. Adult cicadas only live a few
weeks. After six to ten weeks, the eggs hatch, and the nymphs drop to
the ground and burrow to find a suitable food source such as roots, where
they begin their 13 or 17 year long development.
Why
are there so many of them?
Scientists believe that the significant number of cicadas in a periodic
species is an evolutionary adaptation to ensure survival of the species.
This also helps to explain why the cicada has not developed a biting or
stinging defense mechanism; the sheer number of cicadas in the population
practically guarantees that predators will not be able to eat all of them.
Thus, individual defense mechanisms are limited to the "squawks,"
or loud protest noises, cicadas make when handled or disturbed.
Are cicadas dangerous?
Cicadas do not bite or sting and are considered harmless to people or
animals. In fact, they provide an abundant food source for many other
animals. If handled cicadas may emit a loud "squawk," which
is more startling than anything else. Although you may need to sweep them
off the pavement or from other places, bug-sprays to kill or repel them
are not needed since they do not harm people or cause significant property
damage.
What
if my cat or dog eats a cicada?
Cicadas are not poisonous and many animals happily make a meal of these
insects. The sheer number of cicadas may tempt an animal to over indulge,
which may be hard on your pet's digestive system. Nevertheless, you should
not be concerned if your pet takes a liking to cicadas.
Will cicadas damage my garden or lawn?
Cicada nymphs do feed on the plant fluids and roots of woody vegetation.
Most shrubs and trees, however, can withstand even heavy infestations
of cicadas. However, the egg laying by adult females can cause damage
to vegetation. Because they deposit eggs on the growing tips of trees
and shrubs by cutting the vegetation, it may cause the terminal end of
the twig to die. Mature trees and shrubs generally will recover from the
short term infestation. You may want to protect young shrubs or trees
by using a physical barrier, such as cheesecloth or fine netting. Pesticides
are not necessary.
Cicadas should
not be confused with locusts.
Locusts are grasshoppers in the order Orthoptera and have chewing mouthparts
and a voracious appetite through their life. Cicadas, in the order Homoptera,
have sucking mouthparts (like little soda straws) and feed only as nymphs
underground, on tree roots. They are in the same family as the familiar
annual dog-day cicadas whose songs are associated with hot summer days.
The DON'TS
1. Don't use pesticides. Because the cicada are harmless, use of
pesticides is unnecessary. Besides, ciacas are flyers - the cicadas from
the neighbor's yard will fly right into yours.
2. Don't panic. They're only bugs, and while they look fearsome
and fave hard body parts, they don't bite and sting like some bees and
flies do.
What you can expect.
1. The bodies of dead cicada littering the ground.
2. The constant hum of cicadas singing during the warmest part of the
day.
3. An occasional cicada landing on you.
4. An occasional cicada crawling on a table, chair, or barbecue.
5. They will be gone in a few weeks to begin their 17-year cycle all over
again.
TAKE
ACTION: A great opportunity to teach children about insects and
how we can and do live with them. This learning experience is a teachable
moment of how insects are part of biological systems and using pesticides
is not necessary. Contact Beyond
Pesticides (202-543-5450) or see our website's alternative
factsheets to learn about all the alternative approaches to pest management
that are effective without toxic pesticides.
Additional Resources
For more information on cicadas, including sound clips, pictures, and
maps, please explore the following web sites. These are just a sampling
of information available about cicadas.
Beware
of those advising pesticide use for cicadas, including some state authorities.
General Information: Fact
sheet from the National Agricultural Library, U.S. Department of Agriculture.
Illinois:
Newsletter article about cicadas in Illinois.
Indiana:Describes
the Indiana University Cicada Project, which is investigating the causes
and consequences of the 2004 cicada outbreak. Fact
sheet on periodical cicadas in Indiana.
Maryland:Fact sheet about cicadas.
Links to information
for homeowners, landscape professionals, teachers and students
Massachusetts:
Fact sheet with photos of various life-stages of cicadas and their egg-laying
behavior.
Michigan:Cicada
life cycle and photos
Ohio:Fact
sheet on cicadas in Ohio
Pennsylvania:Information
about cicadas and specifically in Pennsylvania.
Virginia:Includes
information about schedules for emergence of the various "broods"
of cicadas.
Source: EPA
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