Ci rcular 572
e House MOf$quito
and
Its Control
LYLE E. HAGMANN
Associate Research Specialist in Entomology
NEW JERSEY AGRICULTURAL EXPERIMENT STATION
,RUTGERS UNIVERSITY -
THE STATE UNIVERSITY OF NEW JERSEY
NEW BRUNSWICK, NEW JERSEY
THE HOUSE MOSQUITO AND ITS CONTROL
The Culprit
New Jersey has about 45 different kinds (species) of mosquitoes. Although their individual habits vary greatly, the immature stages live in water. The various kinds may need clean or
polluted, fresh or salt, warm or cold water, but they all need
water.
The life cycle of the house mosquito may be completed in 7 to
10 days; as a result many generations are produced each year. All
mosquitoes go through four stages of development - egg, larvae,
pupa, and adult. Because of their characteristic movements in the
water, the larvae are often called "wrigglers" and the pupae
"tumblers." The eggs are laid in groups of 100 to 200 in boatshaped rafts on water surfaces. The larvae feed on microscopic
organisms, such as bacteria, algae, protozoa, and fungi. Although
the wrigglers live in the water, they breathe air. Consequently
they must come to the surface at frequent intervals. Air is obtained through a small tube (siphon) located at the posterior end
of their bodies. The discovery that the larvae must surface for
air resulted in the development of chemical control methods for
use at that time. The wriggler stage is an active feeding period.
Growth is rapid, and within 5 to 7 days the wrigglers transform
to the tumbler stage. During this time, the body form of the
adult mosquito develops. When this development is complete,
adults emerge from the pupae at the water surface.
Females Search for Blood
The adult mosquitoes seek shelter in the nearby foliage as
soon as their wings and body harden and remain quiet until
evening. As dusk approaches, they become active and fly in search
of food. The males feed on plant nectars and are lmable to "bite."
Only the females search for blood. House mosquitoes prefer the
blood of man and domestic animals; however, they will attack
other warm-blooded animals. They readily invade houses. Because
of their small size, defects in window screens and cracks around
windows and doors give them ready access. After feeding, the females mate and again seek shelter in shrubbery, tall grass, or
weedy areas. There they remain until the consumed blood is digested and their eggs are developed. 1bis takes from 3 to 5 days.
ThIS 1S a revis10n of Leaflet 110, published in August, 1953.
The Search for Water
Since the survival of mosquitoes depends upon finding water
for egg laying, no stagnant water surface escapes detection.
Polluted water is most attractive to these insects; therefore,
polluted streams, open sewage ditches, cesspools, street catch
basins, and flooded cellars are the preferred sites for egg
laying. Rainwater in tin cans (see cover illustration), old paint
buckets and tire casings, birdbaths, ornamental pools, and
clogged roof gutters also serve as ideal places for egg laying.
Construction of housing developments during the summer months
create numerous breeding places. Some of the usual water-holding
places in these developments are foundation excavations, sanitary
ditching, wheel tracks, and low spots caused by faulty grading.
Winter Survival
Adult mosquitoes that emerge after the onset of cool weather
in the fall mate, and the fen~les seek sheltered places in which
to hibernate. Preferred places for hibernation are well pits,
cellars, sewer and service tunnels, and crawl spaces under houses.
They remain dormant until the following spring. Reactivated by
the warm weather, they feed and lay eggs, starting the cycle anew.
Control
Mosquitoes can best be controlled in the wriggler stage,
either by eliminating the stagnant water in which they live or by
chemical treatment. Control of adult mosquitoes is practical only
under special conditions.
In local areas the following recommendations are suggested:
1. Proper disposal of tin cans, paint buckets, old tires,
and rubbish.
2. Clean clogged roof gutters and drain flat roofs.
3. Change water in birdbaths, fountains, and troughs twice
weekly.
4. Flush sump-pump holes weekly if they contain wrigglers.
5. Seal cesspool covers and vents.
6. Treat foundation excavations, wheel tracks, depressions
caused by improper grading, and small swampy areas with
fuel oil or a 2 percent DDT fuel oil solution at weekly
intervals.
The house mosquito may be prevented from cominr- indoors by
properly screening windows and sealing cracks around the doors.
Window screens and door frames may be sprayed with a household
'--\6S;'\-b
DDT spray two or three times during the summer as a further preventive measure. Mosquitoes that do find their way inside may be
killed by using an aerosol insecticide ITbomb." These aerosol
sprays may also be used in basements to eliminate the hibernating
adults that come in during the fall.
Mosquito repellents commercially available will provide satisfactory individual protection for 1 to 3 hours. This is dependent
upon the temperature and the outdoor activities in which the individual is engaged. Insect Repellent 6-12, Skat, Skol, and Mosquitone Stick are some of the products available at drug and department stores.
In areas adjacent to polluted streams and swamps and uncovered
dumps, the problem is usually too large to handle on an indivi.dual basis. Under such circumstances, the assistance of your
county mosquito extermination commission should be solicited.
This group is equipped to install drainage facilities or to apply
insecticides to eliminate the nuisance.
Cooperative cleaning up of "backyard breeding places" by local
community action will enable your county mosquito control organization to concentrate on the larger mosquito problems.