Preventive Treatments for Control of Cockroaches
in Urban Housing and Food Service Carts
R. C. MOORE
The Connecticut Agricultural Experiment Station
New Haven • Bulletin 740 * December 1973
Digitized by the Internet Archive
in 2011 with funding from
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Preventive Treatments for Control of Cockroaches
in Urban Housting and Food Service Carts
R. C. MOORE
The German cockroach, Blattella germanica, is the most important
household insect present throughout the year in the United States
(Mampe 1972). Infestations in densely populated inner-city areas of
Connecticut are serious. A survey taken in 1970, in six New Haven public
housing projects, revealed that 60% of the apartments were infested; of
lliese, 18% were classified as very heavily infested (New Haven, De-
partment of Health, 1970). As people move from infested housing into
new low and moderate income housing, they often bring cockroaches
with them. If cockroach prevention measures could be taken during
construction of a building, they might be safer, more effective, and more
economical than present techniques.
Several materials provide tlie lengthy residual activity needed for
cockroach proofing. Dri-die® and Drione® have been reported to be
effective against at least 50 species of arthropods, including seven
species of cockroaches (Tarshis 1964). Ebeling et al. (1965, 1967, 1969)
and Tarshis (1964), reported on successful use in California of inorganic
dusts such as Dri-die 67, Drione, and boric acid for cockroach proofing.
Dri-die (95.3% amorphous silica gel and 4.7% ammonium fluosilicate ) ,
is a nonabrasive, liighly sorptive desiccant dust. It kills by absorbing a
portion of the thin protective lipid layer of the cuticle, causing cock-
roaches to lose water at a lethal rate. Drione is a mixture of Dri-die
(38.12% amorphous silica gel and 1.88% ammonium fluosilicate), pyre-
thrins ( 1.0% ) , and piperonyl butoxide ( 10% ) . Drione also acts as a
desiccant, but the addition of pyrethrins makes it more toxic than Dri-
die, and causes it to kill roaches more rapidly (Ebeling 1971).
Cover— Adult female German cockroach with egg case.
4 Connecticut Experiment Station Bulletin 740
Cockroaches are repelled by Dri-die and Drione ( Ebeling et al. 1966,
Moore 1972), thus treated areas become less attractive as harborages
and breeding places. These same authors have shown that boric acid,
which acts as a stomach poison, has been very effective against cock-
roaches because it does not repel them. Moore (1972) showed that small
amounts of Dri-die 67 or Cab-O-Sil M-5 ( 99% SiOs ) , mixed with boric
acid, increased the toxicity of boric acid with little or no increase in
Baygon® (2-iso Propoxyphenyl-methylcarbamate ) 2% roach bait,
after having been aged for 101 days, continued to kill more than 90% of
the cockroaches exposed in laboratory tests (National Communicable
Disease Center, 1971). Baygon 2% roach bait, followed by a 1.1% Bay-
gon spray, was used successfully by Moore (1971) to reduce infestations
in occupied urban apartments.
Cockroaches are not only a problem in urban apartments, but are
sometimes abundant in hospitals as well. Unique problems in hospitals
are infestations in the insulation of electrically heated food carts and
in cracks and crevices of other utility carts used in food service. These
carts usually are fogged monthly with pyrethrum, but this method of
cockroach control has been unsatisfactory.
In this study, boric acid, Dri-die, boric acid plus Dri-die, boric acid
plus Cab-0-Sil and Baygon bait, were placed in apartments under con-
struction or prior to occupancy to determine their effectiveness in pre-
venting cockroach infestations. Drione was evaluated for control in
electrically heated food carts and utility carts used in a hospital cafeteria.
Materials and Method*
Four buildings under construction in a low and moderate income
housing project in New Haven were selected for evaluation of inorganic
dusts. In building A, with 21 apartments, 11 units were treated with
boric acid plus 0.1% Cab-O-Sil M-5; the remaining 10 units were treated
with boric acid plus 0.1% Dri-die 67. In building B, 15 units were
treated with Dri-die 67 alone. Boric acid alone was used in building C.
The nine apartments in building D were not treated. Technical grade
boric acid powder (Mallicrodt Chemical) was passed through 16-mesh
window screen, before the silica materials, 0.1% Dri-die (FMC Corpora-
tion) or Cab-O-Sil (Cabot Corporation), were added. The materials
were thoroughlv mixed using a motorized mixer.
Figure 1. -Applying dust into wall voids using a pressurized blower.
All apartment walls surrounding the kitchen, bathrooms, and utility
room were treated (Fig. 1) by blowing dust between the walls with a
modified pressurized fire extinguisher (Neil A. MacClean Co.) as de-
scribed by Ebeling et at ( 1967). Some difficulties were experienced when
applying either boric acid or Dri-die alone. After standing several days,
boric acid powder became packed and lumpy. This caused clogging in
the hose of the pressurized duster. Clogging was prevented by screen-
ing and then sifting the boric acid as it was being added to the duster.
Dri-die or Cab-O-Sil are anti-caking agents which prevented lumping of
the boric acid. While most of the Dri-die applied in wall voids will
adhere to treated surfaces, some of it tends to float around excessively
because it is extremely light. This is especially true when it is applied
in open areas such as cabinet tops or under appliances.
Connecticut Experiment Station
The construction of the buildings studied was especially suited for
this treatment. Dust could be blown throughout the wallspace through
a single opening, such as an electrical outlet, because metal studs with
a 4" opening every foot supported the wallboards. In walls without elec-
trical outlets or other openings, a V^' hole was drilled in the wallboard
to inject the dust. Other areas treated with the pressurized duster in-
cluded: 1. the basement area through which all common utility pipes
ran; 2. the area where heating pipes entered wallspaces; 3. false areas
under kitchen cabinets; and 4. enclosed soflfit areas above cabinets. Sev-
eral weeks before tenants began to move in, a hand duster (Getz gun)
was used to treat other cabinet and closet areas and also under and be-
hind kitchen appliances (Fig. 2). Approximately 5 lbs. of boric acid
Figure 2.— Applying dust or bait using a Getz-gun hand duster.
dusts and 2.5 lbs. of Dri-die were apphed per apartment. After tenants
moved into the buildings, the treatments were evaluated by monthly
inspections using a pyrethrin aerosol spray to flush cockroaches into the
Two formulations of Baygon 2% roach bait (Chemagro Chemical
Co.) were tested in the laboratory and in the field. Bait A was formu-
lated by the manufacturer using technical grade Baygon. Bait B used
50% wettable powder. The efficacy was determined by confining
cockroaches to 1 cc deposits in plastic dishes as described by Moore
(1972), and calculating the KD50S (knock-down dose for 50%). Re-
pellency was tested by giving cockroaches a choice between darkened
areas containing bait, and untreated lighted areas (Moore 1972) with
food and water. The numbers of living and dead cockroaches in the dark-
ened, baited area were recorded at 24 hr. intervals.
Field tests with Baygon 2% roach bait were conducted in 30 newly
constructed apartment units in New Haven. Half were treated with
each bait formulation several weeks before tenants moved in. The bait
was formulated as "crevice-sized" particles which could easily be ap-
plied with a Getz gun. Treated areas included those under and behind
appliances, under radiators, in kitchen cabinet corners, on utility room
and closet shelves, in sink cabinets, and in cracks, voids, and other en-
closed areas. Wall voids were not treated. Particular attention was given
to baiting false areas in and under kitchen cabinets because these pro-
vide excellent harborages for cockroaches. Between V2 and 1 lb. was
applied per apartinent. Monthly evaluations were made using the
pyrethrin flushing technique.
Figure 3.— Applying Drione dust to insulation of electrically heated food carts using
a Centra-bulb duster.
Two types of carts were treated in a state hospital facility. Twenty-
five electrically heated food carts and 10 utility carts were treated widi
Drione dust (FMC Corporation). Tlie tops of the food carts were re-
moved and the dusts were applied to the insulation with a Centra-bulb
duster (Fig. 3). Approximately 2 oz. of Drione were used per cart. Ten
utility carts (5 large and 3 small metal carts, 1 large and 1 small wooden
cart) were also treated using an aerosol can containing Drione. The
dust was sprayed on under surfaces of the shelves and into all crevices.
Monthly evaluations were made with pyrethrins.
Connecticut Experiment Station Bulletin 740
Areas of the apartments where cockroach infestations were most frequently found.
of sites infested
Boric acid (BA)
BA + 0.1% Dri-die
BA + 0.1% Cab-O-Sil
Boric acid-silica dust treatments. Results are given only for apart-
ment units which were occupied for the entire first 6 months evaluation
period. The kitchen was the most frequently infested site ( Table 1 ) . As
shown in Table 2, boric acid or Dri-die alone, or boric acid plus 0.1%
Dri-die were the most eflPective. This was true following 6 monthly in-
spections and also at the end of 18 months. In occupied units treated
with these dusts, the infestation rate never exceeded more tlian 20%.
In units treated with boric acid plus 0.1% Cab-O-Sil, 30-50% were in-
fested after 6 months and 60% were infested after 18 months. At least
half of the untreated units were infested when inspected the first time.
No more than 13 cockroaches were flushed out during any inspection
of a treated building, even after 18 months (Table 2).
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10 Connecticut Experiment Station Bulletin 740
Baygon bait treatments. Two formulations of Baygon 2% roach
bait were evaluated in the laboratory (Table 3). When cockroaches
Efficacy of two formulations of Baygon bait for German cockroaches when confined
with bait or in a choice situation.
KDso when roaches
confined with bait
initially placed in
7 9 18
* 3 replicates of 10 adult male German cockroaches.
^ 3 replicates of 20 adult male German cockroaches.
were confined with the bait, it took 34 minutes for 50% to be knocked
down with formulation B, and 59 minutes with formulation A. In the
choice situation, 83% were killed in 7 days with either formulation.
After 18 days, about 10% were still alive.
The results given in Table 4 show that live cockroaches were not
entering darkened baited areas as frequently as the unbaited area. These
observations indicate that cockroaches may have been repelled by the
Percentage of German cockroaches in the dark area of choice boxes treated with
Baygon bait formulation.
% live insects in dark area on day
Numbers of roaches in newly constructed apartments treated with
Baygon bait formulations are shown in Table 5. Two of the 15 newly
constructed apartment treated with Baygon bait, formulation A, were
infested after 3 and 6 months. In units treated with formulation B, one
was infested after 3 months and three after 6 months.
Effectiveness of two foraiulations of Baygon bait for controlling German cockroaches
when buildings were treated prior to occupancy.
1, 4, 25
Drione dust treatments in food caHs. The application of Drione
dust to electric food cart insulation reduced the numbers of roaches in
the carts by 98% after 1 month (Table 6). It continued to control at
approximately this level for 5 months. In utility carts treated with the
aerosol, roaches were reduced by 76% after 1 month and by 95% after
Effectiveness of Drione dust for controlling German cockroaches in electrically heated
food carts and other utility carts.
% reduction after
1 month 3 months 5 months
97.8 98.5 96.3
76.2 95.2 -
^ Electrically heated food carts.
"^ UtiUty carts.
12 Connecticut Experiment Station Bulletin 740
These field tests show that appHcation of dusts such as Dri-die,
Cab-O-Sil or boric acid and Baygon bait to apartments under construc-
tion were a successful control measure. There are several advantages to
treating buildings during construction or before occupancy: 1, Insecti-
cides are safer to apply when units are uninhabited; 2. treatments can
be more thoroughly applied to areas such as cabinets or closets because
they are empty; 3. tenants are not present to interfere with the ap-
plicator; and 4. dust or bait may keep cockroaches brought in by tenants
from getting established.
Drione dust applied to food and utihty carts successfully reduced
roaches. It might be advantageous to treat these carts during construc-
tion. Applications of Drione dust to the insulation of other electric ap-
pliances such as stoves, refrigerators or freezers might also be effective
in reducing cockroach infestations.
Dusts and baits are normally used as secondary or back-up treat-
ments for residual sprays, but these data shows these materials can be
used as the primary control measure. Dusts have a longer residual hfe
than sprays, they penetrate deeper into cockroach harborages, and brief
contact with the dust leaves a lethal deposit on roaches. Baygon bait,
because of its "crevice-size," can be applied directly to the insect
The cooperation of the Keystone Exterminating Co. is gratefully
Cockroach Proofing 13
Ebeling, W. 1971. Sorptive dusts for pest control. Ann. Rev. Entomol. 16: 123-58.
Ebeling, W., R. E. Wagner, and D. A. Reierson 1965. Cockroach control with Dri-die
and Drione. P.C.O. News 25(10) : 16-22.
EbeHng, W., R. E. Wagner, and D. A. Reierson. 1966. Influence of repellency on
the efficacy of blatticides. I. Learned modification of behavior of the German
cockroach. J. Econ. Entomol. 59(6): 1374-88.
Ebeling, W., R. E. Wagner, and D. A. Reierson. 1967. Pressurized powder blower
for applying boric acid. P.C.O. News 27(2): 4-6, 10, 23.
Ebeling, W., R. E. Wagner, and D. A. Reierson. 1969. Insect proofing during build-
ing construction. CaUf. Agr. 25(5): 4-7.
Mampe, C. D. 1972. The relative importance of household insects in the continental
United States. Pest Control 40( 12) : 26-27, 38.
Moore, R. C. 1971. Chemical control of German cockroaches in urban apartments.
Conn. Agr. Exp. Sta., New Haven, Bull. 717: 1-11.
Moore, R. C. 1972. Boric acid-silica dusts for control of German cockroaches. J.
Econ. Entomol. 65(2): 458-61.
National Communicable Disease Center. 1971. Public health pesticides: cockroaches.
Pest Control 39(3): 44-45.
New Haven, Department of Health. 1970. Vermin control demonstration program
final report— How to control them. 93 pp.
Tarshis, I. B. 1964. The use of the silica aerogel insecticides, Dri-die 67 and Drione,
in new and existing structures for the prevention and control of cockroaches.
Laboratory Animal Care. 14(3): 167-84.
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