February 1946 E-681
United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
THE USE OF DDT FOR BEDBUG CONTROL /
By L. S. Henderson
Division of Insects Affecting Man and Animals
DDT has proved to be remarkably effective for the control of bed-
bugs (Cimex leotularius L.). The treatment is simple and economical,
and when properly applied will not only clean up an existing infesta-
tion but will prevent reinfestation for 6 months to a year or more.
Treatment with DDT does not stir up an infestation and cause the
insects to spread to other places in the room or to other rooms in a
building, as may be the case when some contact sprays are applied in
a haphazard manner. After the insects begin to be affected by DDT,
they do not hide as they normally do, but may be seen crawling about
in the open during the daytime. These insects will not live long,
however, for this sort of behavior is evidence that they are not normal
and it can be taken for granted that incoordination of movement,
tremors, and death will follow within a few hours.
DDT has no fumigating effect, nor is it eaten by bedbugs. The DDT
is absorbed into the body of the insect as it orawls over the residue
left on a treated surface after the spray has dried. Although the in-
seats may be killed fairly rapidly by direct contact with the liquid
spray, it may be several hours before death follows contact with a dry
Application of DDT
Advantage should be taken of the residual activity of DDT in using
it for bedbug control. The most important consideration is to apply
the DDT in the proper places.
DDT solution. -- The form of DDT most satisfactory for household
use is a 5-percent solution in deodorized kerosene. The air should not
be filled with spray mist, and it is not necessary to keep the room
closed after the spray has been applied. The DDT solution should be
sprayed direotly onto the surfaces to be treated. The greatest atten-
tion should be paid to the bed, which does not have to be dismantled or
removed from the room to be sprayed. Both surfaces and the edges of
_/ For a discussion of the habits and life history of bedbugs,
see U. S. Dept. Agr. Leaflet 146, 8 pp., 1937.
w 2 so
the mattress should be sprayed lightly; it is not necessary to saturate
the fabric cover of the mattress. The frame of the bed should also be
covered with a thin film of spray. The liquid should not be-applied so
heavily that it stands up in droplets or begins to run off and drip.
As little as 3 fluid ounces of a 5-peroent DDT solution will usually be
sufficient to treat an ordinary double bed and mattress. At this rate
a pint will treat five beds.
Bedbugs may be hiding about the room behind baseboards, window and
door frames, pictures on the wall, or in other secluded places. Although
it may not be necessary to spray the entire room, the infested areas
should be treated.
If there are infestations in chairs or overstuffed furniture, they
should be sprayed, because insects in these places will have opportuni-
ties to feed without going to a bed. The greatest attention should be
paid to the underside, any spaces between the frame and the edge of the
upholstery where it is tacked in place, and other spots where the in-
sects are hiding.
Sometimes bedbugs may be found infesting chairs and desks in
offices, furniture in rest rooms or waiting rooms, or seats in theatres
or auditoriums in frequent use. Spraying the various hiding places
about seats, furniture, or other infested objects will give satisfactory
Eqient for application. -- Although certain types of equipment
are preferred for the application of DDT residual sprays, most any sort
of sprayer can be used, and in an emergency a fairly satisfactory appli-
cation can be made even with a paint brush. The ordinary household
sprayer can be used. The most desirable sprayer is one that produces
fairly coarse spray droplets -- what is known as a "wet" spray -- rather
than very fine droplets which form a mist. An electric power sprayer or
paint sprayer can be used if there are adjustable controls so that the
liquid flow can be increased and the air flow can be decreased to form a
rather coarse droplet spray. In some cases the spray attachment on a
vacuum cleaner can be used, if the spray nozzle is held fairly close to
the surface being sprayed. Many of these sprayers, however, have a
teAdency to form a high proportion of tiny mist particles which float
off into space and fill the air with fog, rather than adhering to the
surfaoe at which they are directed.
DDT dust. -- A 10-percent DDT dust can give satisfactory control of
bedbugs and s best applied with a small hand duster of the bellows,
bulb, or plunger type. A thin film of dust should be applied to the
mattress and to the spring and bed frames. The nozzle of the duster can
be used to advantage to blow the powder into cracks and crevices or
other hiding places. The dust will not adhere to vertical surfaces very
well; moreover, the white residue may be objectionable. For treating an
ordinary double bed with the 10-percent DDT dust 1 to 1I ounces will be
Combination DDT srays -- kany household sprays contain approxi-
mately 1 percent of DDT together with some other toxic ingredient.
These sprays may be excellent for direct contact action, but the insects
must be hit with the liquid for it to be effective, and this type of
spray should not be depended upon for residual treatment. It has been
found that for residual effect 5 applications of a 1-percent DDT spray
are not so effective as one application of a 5-percent DDT spray.
Aerosols. -- The aerosol insecticides containing 3 percent of DDT
and 2p~ of pyrethrum are not recommended for bedbug control.
Some insects may be killed by the use of heavy doses in a closed room,
but the aerosols have little penetrating power, and many insects in
protected places will not be affected. The aerosol method is not an
effective means for applying a DDT residual treatment.
DDT is a toxio material, but the experience of the Bureau of
Entomology and Plant Quarantine, extensive use by the armed forces,
and experimental work on animals by the U. S. Food and Drug Administra-
tion and the National Institute of Health have shown that it can be used
with safety as an insecticide in the forms and methods recommended, if
normal precautions are exercised.
Breathing of excessive amounts of mist from the 8-percent solution
in oil should be avoided. Breathing of any considerable amount of oil
vapor or mist alone should also be avoided. If the recommended coarse
spray is used, there will be a minimum of undesirable fine mist in the
air. During the course of an ordinary home treatment with the proper
type of spraver there will be little risk, especially if there is ade-
quate ventilation. If extensive spraying is to be done under poorly
ventilated conditions, it will be advisable to wear a mask or respirator
to avoid irritation ~!ch might be caused by breathing kerosene or large
amounts of DDT. A simple and effective mask for home use may be fashioned
from several thicknesses of gauze.
After a few hours of drying, a sprayed bed may be made up and used
without injurious results to the occupant. Adequate ventilation will
assist in bringing about more rapid drying of the oil spray.
Excessive or repeated exposure of the skin to an oil solution of
DDT should be avoided. The oil solution should be washed from the skin
with soap and warm water. Contact exposure to DDT dust or the dry resi-
due after the base oil has evaporated is not dangerous. The original
spray mist settles out of the air in a few minutes, and after that there
is no danger from being in a closed room which has been treated with DDT.
UNIVERSITY OF FLORIDA
IIlllllll i5lll lll i II I ltll llll ill II II I
4 3 1262 09238 7298
As with all oil sprays, the spray mist of the DDT solution should
not be exposed to open flames or heated surfaces. The fire hasard from
the use of the oil solution of DDT will be practically the same as that
involved in the use of the usual household fly spray.