United States Department of Agriculture
Bureau of Entomology and Plant Quarantine
LUP RY Agricultural Research Administration
STATE PLAiNT BOARD
A DIGEST OF INFORMATION ON ALLETHRIN
R. C. Roark
Division of Insecticide Investigations
*U. S. GOVERNMENT PRINTING OFFICE : 1952 0 221857
Introduction ............................................................. 4
Nomenclature .............................................................. 4
Physical characteristics .................................................. 5
Synthesis of allethrin ................................................. 6
Synthesis of chrysanthemum monocarboxylic acid ......................... 7
Synthesis of 2,5-dimethyl-2,4-hexadiene ................................ 8
Alternate synthesis of 2,5-dimethyl-2,4-hexadiene ...................... 8
Analysis .................................................................. 9
Production ............................................ .................... 11
Patents ................................................................... 12
Specifications .............................. .............................. 12
Allethrin in aerosols .................................................... 13
Stability of allethrin and its formulations ............................... 14
Use of synergists with allethrin
MGK-264 .............................. ..................... .. .. .. .. .... 15
n-Propy isoK-264me....me ... ............... ........... ...... ........ .......... 15
Sulfoxide ........ ........ ..... ... ..... .. . . .. . 16
Piperonyl butoxide ..................................................... 16
m-Nitrobenzamides ..................................................... 17
Comparative value of synergists for allethrin ........................ 17
Allethrin stereo somers ................................................... 20
Analogs of allethrin ..................................................... 22
Toxicology ................................................................ 23
Classification of insects against which allethrin has been tested ......... 26
Blattidae . ........................................................... 26
Thripidae ........................................................ ...... 27
Aleyrodidae ............................................................ 27
Aphidae ................................................................ 28
Cicadellidae ........................................................... 29
Coccidae ............................................................... 29
Coreidae ............................................................... 29
Lygaeidae .............................................................. 30
Miridae ............................................................... 30
Pentatomidae ........................................................... 30
Pediculidae ............................................................ 30
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Anobiidae ............ .... 31
Chrysomelidae .............................. ........................ 31
Coccinellida ...................................................... 32
Cucujidae .......................... ........... .... ............... 32
Curculionidae ...................................................... 32
Dermnestidae ........................................................ 32
Scarabaeidae ............................... ........................ 33
Tenebrionidae ........................ ............................. 33
Hyponomeutidae ....................... ............................. 33
Papilionidae .............. .................... ..................... 33
Phalaenidae ........................................................ 34
Phycitidae ...... .. .................... . ...... . .............. 34
Pieridae ................................................ .............. 35
Pyraustidae ............................. . .......................... . 35
Sphingidae ........ ........ . ........... . .............................. 35
Formicidae ......................................................... 36
Culicidae .......................................................... 36
Drosophilidae ...................................................... 37
Hippoboscidae .................................. .................... 37
Mycetophilidae ............................... . ..................... 37
Muscidae ..................... . . .. .. .. .............................. 38
Tabanidae .......................................................... 40
Argasidae .............. ............................................. 40
Ixodidae ........................................................... 41
Tetranychidae ...................................................... 41
This digest has been prepared in response to numerous requests for
information concerning the Bureau of Entomology and Plant Quarantine's
new synthetic insecticide, allethrin. This product, because of its high
toxicity to insects and its non-toxicity to warm blooded animals, has
excited great interest among entomologists, chemists, insecticide manu-
facturers, food processors and public health officials. Information on
the chemistry, economic status, toxicology and insecticidal value of
allethrin has been collected and is presented in the form of a digest in
which reference is made to many anonymous articles, press releases and
advertisements in order to present in detail the early history of the
development of allethrin by the Bureau. These references would normally
not be included in a bibliography issuing from the Bureau of Entomology
and Plant Quarantine.
- 4 -
iiFRoYJ 7T ION
The achievement of Schechter, LaForge and Green in synt'-e-i:"inj
allethrin was first made -oublic by Bi-pr;pp (47) in a statement dated
March 11, 1)L9.
Although considerable work had been done by Swiss and 3-itish
workers on the chemistry of the active principles of pyreth.in flowers,
the final structures of pyrethrins I and II and cinerins I and II were
determined mainly by LaForge and associates in 1947 as the result of
15 years of research. Cinerin I was chosen as the object of synthesis
because of its simpler structure and greater stability. Workers in
En,,lanJ had already devised an improved synthesis of chrysanthemum mono-
carboxylic acid, the acidic portion of the molecule. The problem there-
fore was reduced to the preparation of cinerolone, the ketoalcoholic
part of cinerin I. In 191 Schechter, Lavorge and Green finally were
able to devise a general synthesis for cyclopentenolones of the type of
cinerolone and a stereoisomer of cinerolone was prepared. 14hen esterified
with chrysanthemum monocarboyrlic acid it gave a product highly toxic to
house flies. Other analogs were also prepared, but the ester which proved
to be the best with regard to toxicity and knockdown effect on house flies
and also from the standpoint of commercial production was the ester having
an allyl side chain.
The United States Department of Agriculture (l_9) on March 18, 19L9,
issued a press release announcing this new pyrethrum-like chemical and
on May 1 of the same year it issued a picture story (l1S) which depicted
LaForge, Schechter, Green and Gersdorff )erfor-in7 operations having to
do with the synthesis and biological testing of the new synthetic. The
information in there departmental releases quickly appeared in the public
oress and in trade and technical journals (1-5) where the synthesis of
allethrin was hailed as an achievement comparable with that of the syn-
thesis of rubber.
The product now called allethrin was referred to as a "pyrethrin-
like ester" and as a "homolog of cinerin I" in the original release by
Bisho-op. The release of March 18, 1949 referred to "pyrethrum-like
chemicals" and the picture story of May 1, 1949 mentioned "synthetic
pyrethrum-like material" and the "new pyrethrum synthetics". Items in
technical and trade journals referred to Schechter and La:For~e's achieve-
ment as the synthesis of an "isomer of cinerin I" and of a "''o-.olog of
cinerin I". In July 1949 an editorial in a trale journ-l (A'ion. 6) spoke
of "synthesizing pyrethrum" and a news item in the s-me issue (Anon. 7)
was headlined "Penick synthesizes pyrethrumn" although taie article stated
that the "allyl homolog of cinerin I" had been produced. Later articles
referred to "synthetic '-rethrins", "so-called synthetic pyrethrum", and
This confusion in names was ended when the new name "allethrin"
was coined by the Interdepartmental Committee on Pest Control (Roh-qer
150) to designate the insecticidal chemical dl-2-allyl-4-h[,-r o :--
methyl-2-cyclopenten-l-one esterified with a mixture of cis and trans
dl-chrysanthemum monocarboxylic c.cids. Although not officially announced
until May 15, 1950, "allethrin" as revealed as the new name for the
allyl homolog of cinerin I on M1-rch 20, 1950 at a meetirn- at the Boyce
Thompson Institute, Yonkers, New York, sponsored by the Carbide and Carbon
Chemicals Division of the Union Carbide and Carbon Corporation for the
purpose of announcing the first commercial synthesis of allyl cinerin
Before the name allethrin was announced Starr et al. (172) sug-
gested that the allyl homolog of cinerin I be called "devinylpyrethrin
I", or in abbreviated form "DPy I". In England allethrin has been
called "allylrethrin" (Blackith 1) and Harper's (06) nomenclature
"synthetic dl-allylrethronyl dl-cis-trans-chrysanthemate" has been used
by Galley (j) and by Elliott et al. (66).
Although Rohwer's announcement applied the name allethrin to the
"substantially pure" chemical those in the insecticide industry have
urged that it mean 100 percent material (Moore 11).
Certain trade names have been applied by S. B. Penick and Company
to allethrin, for example, Allexcel 20 (l43) and Pyresyn (19, l44).
According to Frear (74) Allexcel 20 contains 1 percent of allethrin,
5 percent of n-propyl some, 10 percent of butoxyetbhanol, and 84 percent
of oil. Allexcel g0 emulsifiable contains 3 percent of allethrin, 2g.4
percent of n-propyl some, 20.3 percent of methylated naphthalene and 12.1
percent of oil. Pyresyn technical contains 75 percent of allethrin and
25 percent of related compounds.
Commercial allethrin has the following physical properties .-McNamee
(120, 121), Moore (131).
Appearance Clear, brownish
Color on Gardner scale 15
Specific gravity at 20/20 1.005-1.015
Refractive index at 30* C. 1.5010-1.5035
Refractive index at 20 C. 1.504o
Acidity calculated as
acid < 3 percent
Odor Kild, unobjectionable
Yreon n-oluble < 0.1 percent
The synthesis of allethrin is accomplished in 13 steps, 6 steps in
making allethrolone, 6 steps in making chrysanthemum monocarboxylic acid
chloride, and a final step in combining these two components.
The reactions involved are shown below.
Synthesis of Allethrin
CH3COCH2COOC2H5 (Ethyl acetoacetate)
+ CH2 = CHCH2Cl (Allyl chloride)
+ NaOC2H5 (Sodium ethylate)
CH3COCHCOOC2H5 (alpha-Allyl acetoacetic ester)
CH 2CH = CH
CH2 = CHCH2CH2COCH2CO0
CH2 = CHCH2CH2COCH2COC
C2H5 (gamma-Allyl acetoacetic ester)
K (salt of gamma-Allyl acetoacetic acid)
+ CH3COCHO (Pyruvaldehyde)
CH3COCHOHCH2COCH2CH2CH = CH2 (3-Hydroxy-8-nonene-2, 5-dione)
CH2CH = CH2
- 7 -
(CH)2C = CH CH
(Chrysanthemum monocarboxylic acid chloride)
H / >\
(CH3). c CH2CH = CH2
(cH3)2c = OH CH H
H2C-- = 0
Synthesis of Chrysanthemum Monocarboxylic Acid
C2H500CCH2NH2.HC1 (Glycine ethyl ester hydrochloride)
+ Acid + NaN02 (Sodium nitrite)
C2H50OCCHN2 (Diazoacetic acid ethyl ester)
+ (CH3)2C = CHCH = C(CH3)2 (2,5-Dimethyl-2,4-hexadiene)
+ Copper catalyst
(cH3)2C = CH-CW
. | CHCOOH
(c3)2c = c-..c.
+ SOC12 (Thio
(cH3)2C = CH-CH
(Chrysanthemum monocarboxylic acid ethyl ester)
(Chrysanthemum monocarboxylic acid)
(Chrysanthemum monocarboxylic acid chloride)
Synthesis of 2, 5-Dimethyl-2,4-Hexadiene
(2, 5-Dimethyl-3-hexyne-2, 5-diol)
+ Catalyst + H2
(2, 5-Dimethylhexane-2, 5-diol)
(CH3)2C = CHCH = C(CH3)2 (2,5-Dimethyl-2,f4-hexadiene)
Alternative Synthesis of 205-Dimethyl-2,4-Hexadiene
CH2 = c(cH3)CH2C1
CH2 = C(CH3)CH2CH2C(CH3) = CH2
(CH3)2C = CHGH = C(CH3)2
The details of the reactions are described in the following papers:
..p_1: 100# 15 _.p 1 1541 152s.
157. 158. ;6Z. 161.
Cunples (62, 6) determined the infrared spectra or n tural cin-
erolone and synthetic 2-(2-butenyl)-4-bdr'-3-ethyl-2-rlopenten--
one over the wave length of 2 to 15 microns. The soectra indicate that
the compounds are cis-trans isomers and that the naturally occurrin-
compound is the cis form and the synthetic comnound the trans form. The
spectra confirm the molecular structures as determined by Harper and by
LaForge and coworkers.
In 1952 LaForge et al.(113) reported that esters of allethrolone
are saponified to the combined acid and to 2-allyl-3-methyl-2,4-cyclo-
pentadienone which undergoes the Diels-Alder reaction yielding a dimeric
compound as the main product. The dimer exhibits the reactions character-
istic of carbonyl bridge compounds. It furnishes both a mono- and a
disemicarbazone and upon heating sheds carbon monoxide with formation of
a tetrasubstituted indanone. These reactions of allethrolone esters on
saponification probably would occur with all esters of 4hh.droxycyclopen-
tenones including the pyrethrins.
Technical allethrin as produced commercially contains between 75 and
95 percent of allethrin. Of the methods proposed for the assay of technical
allethrin, the hydrogenolysis method and the ethylenediamine method are
the two that are chiefly used at present. "Both are considered tentative
methods by the Insecticide Chemical Analysis Committee of the Chemical
Specialties Manufacturers Association.--Haring (93, 914).
The hydrogenolysis method is based on the method proposed by LaForge
and Acree (Soap and Sanit. Chem. 17(1): 95-98, 115) in 194l for the
determination of the pyrethrins and depends on the cleavage of the ester
by hydrogenation of the sample in isopropanol employing a palladium oxide-
barium sulfate catalyst. The location of the cleavage is shown in the
following structural formula:
In addition to hydrogenolysis of the ester group and saturation of
the double bonds, it is probable that the cyclopropane ring of chrysan-
themum monocarboxylic acid is opened. The acidity produced is titrated
- 10 -
after filtration of the solution. In one version of the method, the
titration is carried out at the boiling point, whereas in a later version,
the titration is performed at room temperature. In the latter case, an
amount of alkali equivalent to the free acidity of the sample plus 1.00 ml.
of 0.1 N alkali is added to the solution before hydrogenation to activate
the catalyst. Ap-oropriate corrections are made for the free acidity originally
present in the sample, for rea.-ent blanks and for the catalyst activity.
The ethylenediamine method proposed by the Carbide and Carbon Chemicals
Company depends on the followin- reaction of allethrin with ethylenediamine:
HC-COO -- CH C-CH2-CH=CH2
( CH,) 2C=CH-CH-C( CRH3)2^Cg -
Hc- COOH. NH2CH2 CH2pH2
(CH3) 2C=CH-CH-C( MH3)2
CH C..CH2-CH=CR2 -. Dimer -. Polyut,
S CH --- 0=0 Cyclic iminc
After the addition of pyridine, the chrysanthemum monocarboxylic
acid is titrated with 0.1 N sodium methylate in pyridine. Suitable cor-
rections are made for blanks on reagents, and for chrysanthemum .onocar-
bo-Tyrlic acid, acid chloride, and acid anhydride originally present in the
sample. The reaction with ethylenediamine is carried out for 1/2 hour at
98 C. or for two hours at room temperature (25C. + 2 C.).
A color test for allethrin vsrc- described in 1952 by Feinstein (72).
A solution of 2-(2-aminoethylaynno) ethanol in ethanol and alcoholic potassium
hydroxide will give a red or violet color with allethrin (or pyrethrins) if
sulfur is added. The mechanism of the reaction is not knoun. Pure allethro-
lone, allethrolone semicarbavone, chrysanthemum monocarboxlic acid and
pyruvic aldehyde do not react under the conditions present.
- 11 -
In November 1951 the rate of commercial production of allethrin was
Pounds per Year
Benzol Products 25,000
Carbide and Carbon 20 to 25,000
U. S. Industrial Chemicals none
The future production was estimated to be:
Benzol Products 100,000
Carbide and Carbon 450 to 500,000
U. S. Industrial Chemicals 100,000
In the autumn of 1951 it was announced that Carbide and Carbon Chemicals
Company was starting construction of a 6-million dollar plant at Institute
(near Charleston), West Virginia for the production of allethrin. The first
allethrin produced in this plant will be available in 1954.
The commercial production of allethrin within a year of the announce-
ment of its synthesis in the laboratory was an outstanding accomplishment
and Haller (8) stated that industry should be congratulated for having
done a fine job in so short a time.
In April 1952 the U. S. Industrial Chemicals Company (191) announced that
its new allethrin plant in Baltimore would be completed and in operation by
Benzol Products Company's plant at Piscataway, New Jersey in June 1952
doubled its capacity for making allethrin pushing it to 100,000 pounds a
year. The new capacity is an eight-fold increase in less than two years.--
The allethrin produced since full scale production began more than one
year ago is equivalent to approximately half of the high content pyrethrum
imported during the same period. Such a consumption demonstrates conclusively
its effectiveness when skillfully used. More than 12,000,000 allethrin
aerosol bombs have been sold, and millions more are now being produced.--
McLaughlin Gormley King and Company (119) and Anon. (38).
The National Production Authority (Il) at a meeting held January 30,
1952 announced that no shortage of allethrin had developed so far. Military
requirements for use in aerosol bombs have not been sufficient to limit
availability for civilian use.
The price of allethrin (100 percent basis) has declined from $55 a
pound in 1950 to $32 a pound in August 1952.--Torpin (178) and Anon. ().
On February 8, 1949 Schechter and LaForge (158) filed an application
for a patent in the United States Patent Office for a process of making
hydroxydiketones which can be cyclized to cyclopentenolones utilizable
as intermediates in the synthesis of esters closely related to the pyrethrins
and having their characteristic insecticidal properties. On November 13,
1951 part of this application was granted as U. S. patent no. 2,574,500.
This patent is dedicated to the free use of the people in the territory
of the United States.
U. S. Patent 2,603,652 granted Schechter and LaForge (15.) on July
15, 1952 covers allethrin and similar esters. The methods of making
allethrolone and analogous cyclopentenolones and of acylating these
compounds are described. The knockdown and mortality of houseflies sprayed
with solutions and aerosols of different esters are given.
The foreign rights to this invention and to the inventions described
in pending United States patents describing the synthesis of pyrethrin-
like chemicals were acquired early in 1950 by U. S. Industrial Chemicals,
Inc. (Anon. 16). Corresponding applications have been filed in all major
foreign countries including the United Kingdom, France, Australia, India,
Brazil, Sweden, Pakistan, South Africa, and many others.
Allethrin has been approved by the United States Department of Agri-
culture for use in sprays and dusts in meat packing plants subject to the
same restrictions that govern the use of pyrethrum.--Miller (12,p 129).
The U. S. Department of the Army (18) on December 6, 1950 issued
military specification MIL-I-10745 (QMC) for a 12-ounce insecticide aerosol
dispenser. This specifies the uBe of 0.6 percent of allethrin (not less
than 75 percent purity) for the type A insecticide or 0.4 percent of
pyrethrins for the type B.
On March 20, 1952 this specification was superseded by MIL-I-10745A
(189) whichspecifies a minimum content of 0.6 percent by weight of allethrin
for the type I insecticide. The technical allethrin shall contain not less
than 75 percent allethrin nor more than 8.0 percent total free acidity when
calculated as chrysanthemum monocarobxylic acid. The material shall have
not more than 0.5 percent dichlorodifluoromethane insoluble material as
determined by the method described in Munitions Board Purchase Specification
P-42 for pyrethrum extract.
- 13 -
Military specification MIL-I-11355 (188) dated August 14, 1951 for
insecticide powder calls for a minimum of 0.30 percent by weight of allethrin
for the type I insecticide. Other ingredients are 0.2 percent of pyrethrins,
2 percent of sulfoxide, 5 percent of chloromethyl p-chlorophenyl sulfone,
0.25 percent of antioxidant, 2.7 to 3.3 percent of conditioner and diluent
(pyrophyllite) to make 100 percent.
In July 1951 the Department of the Army revised purchase directives
for the space spray covered by the Military Specification MIL-I-10177 and
substituted allethrin at0.15 percent in place of pyrethrins at .1 percent.
During 1951 85,000 gallons of this allethrin space spray were purchased.
The General Services Administration (19.0) on April 1, 1952 issued
interim federal specification 0-1-511 (GSA-FSS) for a liquid space spray
insecticide which calls for 0.15 to 0.18 percent by weight of allethrin,
0.75 to 0.85 percent of piperonyl butoxide, 0.95 to 1.05 percent of DDT,
0.04 to 0.06 percent of odor neutralizer and deodorized kerosene to make
ALLETHRIN IN AEROSOLS
As soon as allethrin became commercially available it was tested as a
replacement for pyrethrum extract in liquefied gas aerosols.
Schroeder and Berlin (163) in 1950 reported that when applied in low
pressure aerosols containing 15 percent of non-volatile material and 85
percent of a mixture of Freon 11 and Freon 12 as a propellent, allethrin
at 1.2 and 1.4 percent concentration was slightly superior to pyrethrins
at the same concentration in both knockdown and kill. These aerosols were
tested at an average dosage of 4 grams per 1000 cu. ft. Combinations of
allethrin with piperonyl butoxide were about one-half as effective as simi-
lar combinations of pyrethrins with piperonyl hutoxide. The addition of
2 percent of DDT did not change this ratio. Mixtures of allethrin and
pyrethrins in combination with piperonyl butoxide showed only the addition
effect of two materials having dissimilar synergistic relationships.
Maughan et al. (125) tested aerosol formulations containing allethrin
or pyrethrins with DDT, MGK 264 and lethane 384 against 5-day old house
flies of the CSMA strain. Four percent of lethane 384 adequately replaced
0.3 percent of allethrin when 2-percent of DDT was present in both formu-
lations. It was concluded that combinations of allethrin, lethane 384,
and a synergist (MGK 264, n-propyl some, Sulfoxide or piperonyl butoxide)
will result in highly satisfactory aerosol formulations with or without pyre-
Fales (67) at the 1951 mid-year meeting of the Chemical Specialties
Manufacturers Association reported that allethrin had proved acceptable for
use in aerosols, and may be used in combination with pyrethrins, or lethane.
One very effective formula contains the usual DDT, 2 and 4 percent lethane,
and 0.1 percent allethrin with no synergist. In a typical aerosol formula,
containing 0.2 percent pyrethrins and synergists, part of the pyrethrins
(as much as one-half) may be substituted by allethrin. Aerosol formulas
- 14 -
recommended for use on aircraft contain one or 1.2 percent pyrethrins.
These combinations have been reformulated, using allethrin with a resulting
increase in performance.
As the result of these and other reports (cf. Moore 1_.) of favorable
results of tests Rohwer (151) on October 26, 1950 announced that formulas
containing allethrin were acceptable for use in gas-propelled aerosols.
Shortly after this announcement was made it was reported (Anon. 23-2.5)
that the army had okayed use of allethrin in low pressure aerosols, to
replace hard-to-get natural pyrethrin insecticides, and was asking bids
for more than 2 million low pressure aerosols to contain 0.6 percent alle-
thrin, 2 percent DDT, 5 percent alkylated naphthalene, 7.2 percent deodor-
ized kerosene, and 85 percent of a mixture of Freon 11 and Freon 12.
In October 1951 it was announced that the Army would purchase 5,000,000
12-ounce aerosol bombs containing 0.6 percent allethrin through July 1952.
At 2 grams per bomb this purchase requires 22,000 pounds of allethrin.
Resnick and Crowell (1l8) of the U. S. Public Health Service in 1951
reported that allethrin could be substituted for pyrethrum in the standard
G-382 aerosol formulation without loss of effectiveness. The synergistic
action of piperonyl butoxide and MGK 264 has not been as evident in formul-
ations containing allethrin as in those containing pyrethrum extract. These
tests were made on house flies in a modified Peet-Grady chamber.
The U. S. Department of Agriculture has approved about 35 formulas
containing allethrin for use under the licensing agreement governing the
method of applying parasiticides covered by the Goodhue-Sullivan patent no.
2,321,023 of June 8, 1943. These formulas usually contain from 0.10 to 0.4
percent ofallethrin plus DDT, methoxychlor, lethane 384, Thanite, pyrethrins
and various synergists and solvents in a 50:50 mixture of Freon 11 and Freon 12.
STABILITY OF ALLETHRIN AND ITS FORMULATIONS
When exposed to ultraviolet light for 5 hours (equivalent to 5 days
exposure to mid-day sun) and to heat (110 F. for 24 hours and to 120 F.
for an additional 48 hours) allethrin proved more stable than pyrethrins.
These tests were made on mosquito larvae and house flies. An allethrin
residue of 144 mg. per sq. ft. persisted for several months against house
flies and when a synergist (piperonyl butoxide or sulfoxide) was added the
amount of residue could be reduced to 28 mg. per sq. ft.--Granett et J. (86).
Fales et _Q. (70) in 1951 reported that a high pressure aerosol con-
taining 1 percent of allethrin held at room temperature for four months was
equal in effectiveness against house flies to a freshly made sample.
Fales et al. (68) also found that allethrin when formulated into a
high pressure aerosol and stored for 15 months lost none of its effectiv-
ness against house flies. There was no loss in effectiveness when a mixture
of this material and DDT (in a low pressure aerosol) was stored for 10 months.
Allethrin in kerosene sprays showed no loss in effectiveness after 6 months
- 15 -
Fales and associates (71) also reported that in storage tests with
sprays and aerosols containing the ester made with the natural d-trans
,acid there was no loss in effectiveness against house flies.
Schreiber (162) found that the decomposition, in thin layers, of
pyrethrins was reduced to about one-half when mixed with at least an equal
weight of MGK 264 and irradiated under equal conditions with a mercury
vapor quartz lamp (Hanovia Alpine) for six hours at temperatures not
exceeding 135 F. The irradiation described produced a vivid greenish
yellow fluorescence in accordance with Stokes law. A similar though
slightly smaller protective effect was obtained in the irradiation of
allethrin. In each case the degree of decomposition was checked by the
Seil method for the determination of pyrethrin I since the alkaline treat-
ment required tends to decompose also part of MGK 264 thus rendering a
determination ofpyrethrin II quite vague.
USE OF SYNERGISTS WITH ALLETHRIN
Allethrin in aerosols is not activated by the usual pyrethrin syner-
gists to the extent that the pyrethrins are (Fales 6.L7). The same observa-
tion holds true for sprays. This lack of a good allethrin synergist has
stimulated a great deal of testing of compounds for possible synergistic
value but to date nothing outstanding has been found. Stage (169) in 1951
reported that approximately 150 compounds have been tested at Corvallis,
Oregon to determine whether they enhance the effectiveness of allethrin
when used as a residual treatment against adults of Aedes vexans (Meig.),
and A. sticticus (Meig.). Only 16 of the materials showed some promise a'>
synergists, and none of these were especially outstanding.
MWK 264, which is N-2-ethylhexyl bicyclo-(2.2.1)-5-heptene-2,3-dicarbox-
imide, is a valuable synergist when combined with allethrin and pyrethrins
for roach control in both aerosols and liquid sprays. In aerosols MGK 264
may be used at ratios of five to 15 to part pyrethrins or allethrin.--Moore
With the use of MGK 264 with allethrin, aerosol formulations can be
arrived at which are at least equal in effect and often superior to the
tentative official test aerosol of CSMA not only against flies but also
against roaches. Such formulations may contain, for example, 2-3 percent
of DDT, 2 percent MGK 264, and either from 0.10-0.15 percent each of alle-
thrin and of pyrethrins or 0.25 percent of allethrin or 0.20-0.25 percent of
pyrethrins. Also in experimental dusts for agricultural use combinations of
allethrin and 264 have proved effective, for example, against flea beetle,
cabbage worm, and small tarnished plant bug.--Schreiber (162).
n-Propyl some is a condensation product of isosafrole and di-n-propyl
maleate (Synerholm and Hartzell, Boyce Thompson Inst. Contrib. 14: 85-86,
1945. U. S. patent 2,431,845, Dec. 2, 1947). According to Penick and Com-
pany (_] ) it is a synergist for allethrin.
- 16 -
'This isthe name given to n-octylsulfoxide of isosafrole by, Penick and
-"mp(ay. It was formerly written "sulfox-cide."
Stsrr (170) in 1.0J reported that in preliminary tests, a 16 day old
residue of 4.4 mg. of allethrin and 220 mg. of sulfoxide Fer scuare foot on
kraft paper, gave a knockdown of house flies of more than 95 percent in 30
minutes and a kill of better than 95 percent in 24 hours. Exposure was
limited to two hours. After aging 37 days, the knockdown was better than
95 percent in two hours, but the kill dropped to 35 percent. Dcubling the
quantities of materials in the residue increased the time of effectiveness
from 16 days to 11 weeks.
According to Starr (171) a high grade emulsion can be made using
allethrin and sulfoxide. Starr also gave the following formulas for aero-
sols containing allethrin.
Aerosol formulation 105 contains:
Allethrin - - - - - - - 1 percent
Sulfoxide (n-octylsulfoxide of isosafrole) - 5 percent
Ultrasene - - - - - - - -4. percent
Freon ii-----------------45 percent
Freon 11 - - - - - - - .45 percent
Freon 12- - - - - - - - 45 percent
A formula containing:
Allethrin --- -- - - - - - 0.2 percent
DDT--- ------ ---- - --- ---- 2 percent
Sulfoxide - - - - - - - 1 percent
was above C'A''As TOTA in both 1.5 minute knockdown and 2L hour kill at either
3 or 4 grams per 1000 cubic feet.
Sip erconyl butoxide
This synergist contains as its principal constituent alpha-[2-(2-
Schroeder and Berlin (16) in 1950 reported that when applied in low
pre: ..urE aerosols containing 15 percent of non-volatile material and 85
percent of a mixture of e,"ual parts of Freon 11 and Freon 12 as a propellent,
allethrin at 1.2 and 1.4 percent concentration was slightly superior to
pyrthrins at the same concentration in both knockdown and kill. These
aerosols were tested at an average dosage of 4 grams per 1000 cu. ft. Com-
bination of allethrin with piperonyl butxide are about one-half as effective
as similar combinations of pyrethrins with piperenyl butoxide. The addition
of ? percent of DDTdid not cl.arifge this ratio. Mixtures of allethrin and
p -rthrins in combination with piperonyl butoxide showed only the additive
effect of two materials having dissimilar synergistic relationships.
- 17 -
Against resistant house flies in Florida allethrin and pyrethrins plu:
piperonyl butoxide were moderately effective early in 1950, but by the end
of the season none of them provided satisfactory control .--Wilson et al. (_).
Incho and Greenberg (104) tested the synergistic effect of pifronyl
butoxide when mixed with pyrethrins and with its four constituents separately
and also with allethrin and allethrolone esters against house flies by the
turntable method. By the use of a value representing relative synergistic
effect it was shown that the cinerins exhibited a somewhat greater degree of
synergism in a combination with piperonyl butoxide thandid the pyrethrins,
although pyrethrins I arid II showed superior effectiveness to the corresponding
cinerins, both alone and in combination with piperonyl butoxide.
Since none of the separated active components of pyrethrun showed greater
synergistic activity than the standard pyrethrum extract, it may be concluded
that no one of the components of pyrethrum contributed the major portion of
the synergism found with combinations of piperonyl butoxide and pyrethrins,
Although optical and geometric isomerism in the acid portion of the
molecule have a marked influence onthe insecticidal effectiveness of alle-
throlone esters of chrysanthemum monocarboxylic acid when used alone or in
combination with piperonyl butoxide, they have little effect on comparative
Gertler e al. (8) in 1952 reported the results of tests of certain neta-nitro-
benzamides for synergistic action in allethrin fly sprays. The concentration
was 0.5 rMg. allethrin and 20 mg. adjunct per ml. and all tests were made
against house flies by the Campbell turntable method. Acetone was used as
an auxiliary solvent to increase the solubility of the amides in kerosene.
Ten of 22 materials caused significant increase in toxicity. These were
the N,N-dibutyl, diethyl, diisobutyl, diisopropyl, dimethyl, and dipropyl
and the N-isobutyl and isopropyl derivatives of meta-nitrobenzamide; 1,
meta-nitrobenzoylpiperidine and meta-nitro-N-propylbernzamride. The adjuncts
alone showed negligible toxicity.
Comparative value of synergists for allethrin
The comparative effect of piperonyl butoxide, n-propyl some, and MGK
264 in sprays containing either allethrin or pyrethrins in the proportion
of 10 times as much adjunct as insecticide was determined by Gersdorff et
al. (81) in tests against the house fly, by the turntable method. The
joint action of each of the three pyrethrum synergists with allethrin was
of the synergistic type.
Piperonyl butoxide synergized pyrethrins more effectively than it did
allethrin, the mixed spray with the natural insecticide being about 13 times
as toxic as pyrethrins and mixed spray with the i-.mthetic insecticide being
but two and one half times as toxic as allethrin. The synergistic effect ws
- 18 -
therefore five times as great with pyrethrins as it was with allethrin.
Because of the greater toxicity of allethrin, however, this disparity was
decreased somewhat, and mixed sprays containing the synthetic product were
about half as toxic as those containing the natural product.
The ..-,n-rgistic effect of n-propyl some was about three times as
great with pyrethrins as with allethrin, since the pyrethrins mixture was
but little more toxic than the allethrin mixture. The allethrin mixture
was nearly as toxic as the mixture of allethrin and piperonyl butoxide,
but less than half as toxic as the mixture of pyrethrins and piperonyl
Synergist MGK 264 was not so effective a synergist as piperonyl
butoxide, increasing the effectiveness of the spray by two-thirds when
included with pyrethrins and by one-third when included with allethrin.
The synergistic effect was therefore one and one-fourth times as great with
pyrethrins as it was with allethrin. However, because of the greater
toxicity of allethrin the mixture containing allethrin was about twice as
toxic as that containing pyrethrins.
The relative effectiveness of the insecticidal materials, with and
without a synergist, is in the following ascending order, whether the
evaluation is based on the principal toxicant only or on the insecticide
equivalent: (1) pyrethrins, (2) pyrethrins plus synergist MGK 264., (3)
allethrin, (4) allethrin plus synergist MGK 264, (5) pyrethrins plus n-
propyl some, allethrin plus n-propyl some, and allethrin plus piperonyl
butoxide, and (6) pyrethrins plus piperonyl butoxide. The last mixture
was 17 times as effective as pyrethrins by the first criterion and 13 times
by the second.
Allethrin caused slightly slower knockdown than did natural pyrethrins.
However, all sprays caused complete or nearly complete knockdown at the
low concentration of 0.25 mg. of insecticide per milliliter of kerosene.
Piquett (145) in 1949 reported that piperonyl butoxide, piperonyl
cyclonene and n-propyl some increased the toxicity of allethrin to adult
male American cockroaches when applied as dusts containing 0.6 percent of
allethrin and 3 percent of the synergist. Sesame oil was ineffective in
synergising allethrin. Allethrin alone killed 65 percent of the roaches
in 4 days, pyrethrins alone killed 83 percent and the mixtures of allethrin
with the effective synergists killed 75 to 87 percent.
Starr (171) in 1950 gave formulas for the use of MGK 264, n-propyl some
and sulfoxide with allethrin. Allethrin mixed with n-propyl some (1:5),
MGK 264 (1:10), sesame oil extractives (1:3.75), and piperonyl butoxide
(1:8) and tested against house flies by the Peet-Grady method was in general
less effective than similar mixtures of pyrethrins with the synergists.
F.Y 264 aFFared to be almost equally as effective with pyrethrins at the 50
percent mortality level. The difference in effectiveness between allethrin
and pyrethrins with synergists appears to be more pronounced against German
roaches than against house flies. In surface deposit tests on glass plates
about 3 times the dosage of allethrin with piperonyl butoxide is required to
obtain the mortality of roaches given by the pyrethrins-butoxide combination.
- 19 -
Jones et al. (107) in 1950 reported on the first thorough study of
allethrin in combination with the four commercially available pyrethrum
synergists. In Peet-Grady tests with house flies they found that with sesame
oil extractives it required somewhat less than twice, with n-propyl some
about twice, and with piperonyl butoxide over twice as much allethrin with
synergist as pyrethrins with synergist to produce 50 percent mortalities.
Synergist 264 appeared to be almost as effective with allethrin as with
pyrethrins at the 50 percent mortality level.
They also reported that against grain insects such as the confused
flour beetle and the rice weevil, surface deposits of allethrin with iperonyl
butoxide may be less than one-third as effective as those of pyrethrins and
piperonyl butoxide. In dusts against certain truck crop insects a combin-
ation of allethrin with piperonyl cyclonene was generally less effective
than that of pyrethrins with piperonyl cyclonenes, but the difference in
effectiveness varied greatly with the insect species. For example, against
Mexican bean beetle adults and larvae the allethrin-cyclonene dust gave
almost the same mortality as the pyrethrins-cyclonene dust, while against
squash bug adults and nymphs the allethrin combination was very much less
effective than the pyrethrins combination.
In tests with high-pressure aerosols against house flies piperonyl
butoxide, n-propyl some, and sesame oil extractives all showed synergism
with allethrin. There was considerable recovery of flies knocked down with
sesame oil extractives formulation. The formulas containing n-propyl some
acted similarly with allethrin and with natural pyrethrins. The MGK 264
formulas appeared to give slightly better kill when allethrin was used. ThE
knockdown was lower, but the mortality was the same, when piperonyl butoxide
was used with allethrin.--Fales .et al. (70).
Di-n-butyl hexahydrophthalate and dibutyl 1-bicyclor2.2.1]-heptene-
2,3-dicarboxylate (dibutyl carbate) as synergists produced better results
with allethrin than with pyrethrins when tested against the deerfly.--Hoffman
and Lindquist (103).
The comparative effect of sulfoxide and 3,4-methylenedioxybenzyl n-propyl
ether in oil sprays containing either allethrin or pyrethrins in the propor-
tion of five times as much adjunct as insecticide was. determined by Gersdorff
et al. (2) in tests against the house fly bythe turntable method. The two
pyrethrum synergists also synergized allethrin but to a lesser degree than
they did pyrethrins. The intensity of synergism with sulfoxide was 4.7 and
with the benzyl propyl ether 1.3 as great in the pyrethrum mixtures as in
the allethrin mixtures. The mixture of sulfoxide and pyrethrins waslO.8 as
toxic as pyrethrins, whereas the mixture of sulfoxide and allethrin was but
2.3 as toxic as allethrin. The mixture of the benzyl propyl ether and
pyrethrins was 1.8 as toxic as pyrethrin, whereas the mixture of the benzyl
propyl ether and allethrin was 1.4 as toxic as allethrin. However, when con-
sideration is given to the greater toxicity of allethrin as compared with
pyrethrins as well as synergistic effect, the relative effectiveness of the
insecticidal materials falls in the following ascending order, whether the
eva&lu1tion is based on principal toxicant only or on insecticide equivalent:
(1) p' thrins, (2) pyrethrins plus the benzyl propyl ether, (3') allethrin,
(.) all ethrin plu.; the benzyl pr'p.yl ether, (5) allethrin plus sulfoxide,
and (6) 'ethrins plus sulfoxide. Tll.e last-named mixture is nearly 12
tines as toxic as F.Trethr1ins on the first basis and nearly 11 times on the
seco'd. Knockdown of flies was of high order for all mixtures.
'aborat..'r," tests ain a*:t house flies indicate that the pyrethrum syner-
gists sulfo:xide, n-propyl isorme, and M.GK 264. can be substituted for piperonyl
butoxide in the MIL-STD-129 or Type II Interim Federal Specification 0-1-511
space spray. Substitution can be made at equal concentration levels but
sulfoxide and n-propyl some require auxiliary solvents.--Nelson et al. (142).
In tests against house flies by the Peet-Grady method, four synergists
were tested at a concentration of 0.80 percent by weight in deodorized
kerosene solutions of allethrin (0.16 percent). It was concluded that there
are no significant differences between piperonyl butoxide, some, sulfoxide
and sulfone.--Calsetta (5).
In tests of piperonyl butoxide and sulfoxide as synergists for pyre-
thrins and allethrin against the flour beetle Hewlett (102) found sulfoxide
to be six times as potent as piperonyl butoxide when used with pyrethrins
and 1.8 times as potent when used with allethrin. In comparisons of insecti-
cides pyrethrins and allethrins were equally toxic.
Hewlett (1 _l) in 1952 reported that 5 percent of piperonyl butoxide
synergized 3.5 percent of allethrin in solution in Shell oil P-31 in tests
on the flour beetle Tribolium castaneum (Hbst.). The beetles were either
exposed on films of the insecticides on filter paper at 25 C. or were
directly sprayed and afterwards kept at 25 C. The response in the groups
of beetles was determined six and nine days after the start of their exposure
Allethrin is a mixture of 8 stereoisomers which differ in insecticidal
value. This fact should be kept in mind in evaluating reports of its tests
against various species of insects. In this respect commercial allethrin
is analogous to crude benzene hexachloride from which 5 of the 8 theoreti-
cally possible stereoisomers have been isolated. The gamma isomer of BHC
accounts for practically all the insecticidal value of the product, whereas
the beta isomer is responsible for the chronic toxicity of BHC to mammals.
By s,-eparating the gamrr-a isomer of BHC from the crude mixture a product
(lindane) of superior insecticidal value has been obtained and at the same
time the less desirable properties of the other isomers have been left
behind. Although no simple procedure for separating the isomers in commer-
cial allethrin isknown, such an achievement is not impossible.
- 20 -
- 21 -
The 8 isomers in allethrin are:
cis form of 1-acid esterified with 1-allethrolone
" 1-acid d-allethrolone
"ti -acid _-allethrolone
trans form of 1-acid esterified with 1-allethrolone
" l_-acid d-allethrolone
" d-acid d-allethrolone
Schechter and associates inthe Division of Insecticide Investigations,
Bureau of Entomology and Plant Cuarantine are now working on the separation
of these isomers in order to determine their individual activities to dif-
ferent species of insects.
A step in this direction has been accomplished by the separation of
crystalline allethrin, m.p. 50.5-51 C., from molecularly distilled allethrin
by cooling to about 4' C., or by low temperature crystallization from low
boiling petroleum ether. This crystalline product called the alha-dl-_tL.ans
isomer must consist of one of the racemic ester pairs, d-trans acid with
d-allethrolone plus 1-trans acid with 1-allethrolone, or d-trans acid with
1-allethrolone plus 1-trans acid with d-allethrolone; the beta-dl-trans
isomer consists of the other pair. Entomological tests on house flies indi-
cate the alphX-jl-trans isomer to be less effective and the beta-dl-trans
isomer to be more effective than allethrin.--Schechter et al. (l16).
In 1949 Gersdorff (76) reported that the d-chrysanthemum monocarboxylic
acid ester of synthetic 2-(2-butenyl)-4-hydroxy-3-methyl-2-cyclopenten-l-one
(probably a geometric isomer of cinerolone) was as toxic as natural cinerin
I, about one and one-half times as toxic as the mixture of "pyrethrins" con-
tained in the ordinary pyrethrum-kerosene extract. The replacement of the
2-butenyl side chain of these compounds with the allyl group was accompanied
by a nearly 5-fold increase in toxicity whether the acid component was the
dextro natural one or a racemic cis or trans synthetic one. The allyl com-
pound with the natural acid component was the most toxic of any of the known
pyrethroids, 6 to 7 times as toxic as the mixture of "pyrethrins." No dif-
ference in toxicity was found between the compounds of the cis and trans
forms of the acid component for both classes of compounds, the 2-butenyl and
the allyl. (However, see more recent work below). For both classes the
ester with the natural dextro acid component was about 3.8 times as toxic as
an ester with a synthetic racemic acid component. The completely synthetic
isomers of cinerin I were about 0.39 times as toxic as the mixture of
"pyrethrins." The completely synthetic allyl compounds were about 1.8 times
as toxic as the "pyrethrins." The effect of other changes in chemical
structures on toxicity was determined. Knockdown effect was of high order
for all the compounds.
- 22 -
The marked difference in insecticidal value of the allethrin stereo-
isomers due to optical activity was demonstrated by Gersdorff (27). He
reported that the ester made from synthetic allethrolone and natural d-
trans chrysanthemum acid was 6 times as toxic as the natural pyrethrins
against house flies, whereas the completely synthetic ester(synthetic
allethrolone esterified with synthetic l-cis-tr ans chrysanthemum acid)
was 3 times as toxic; that is, the optically active isomer was twice as
toxic as the optically inactive ester.
More recently Gersdorff and Mitlin (.79) reported that the dl-trans
fraction of allethrin was 1.56 as toxic as the dl-Sc_ fraction. The toxic
action of the two fractions when applied in mixtures was identified as
similar action. The trans fraction was 1.33 and the cis fraction 0.85 as
toxic as this sample of allethrin. On this basis the allethrin used in
this study contained about 69 percent cis isomers and about 31 percent trans
isomers. A crystalline compound, separated from the trans fraction, was
only 0.35 as toxic as allethrin and constituted 8 percent of that insecticide.
The remainder of the trafraction was 1.69 as toxic as allethrin and
constituted 23 percent of that insecticide. It is deduced that half of each
of these portions of the trans fraction is relatively nontoxic and that one
of the remaining two isomers, d-tans acid with d-allethrolone and d-trans
acid with l-allethrolone, is 0.70 as toxic and the other 3.38 as toxic as
allethrin. All the separated constituents possessed high knockdown value.
All these tests were made on the housefly by the Campbell turntable method.
Elliott (65) has discussed the relationship of chemical constitution
to the insecticidal activity of substances related to the pyrethrins.
ANALOGS OF ALLETHRIN
When the high insecticidal value of aliehrin and the method of its
synthesis were announced, chemists prepared analogous compounds by combining
synthetic chrysanthemoyl chloride with substituted cyclopentenolones. In
Japan Inoue and associates (106) synthesized lower alkyl- and alkenyl cinerin
homologs in this way. They also synthesized fifty kinds of pyrethroids from
aromatic, aliphatic, terpenic alcohols, dialkylamino-ethylalcohols, monoalkyl-
ethylene alcohols and chrysanthemoyl chloride in an analogous manner. Insec-
ticidal activity of these compounds was tested against the common house fly
in kerosene space spray.
Nagasawa et al. (136) prepared the ethyl analog of allethrin, called
ethythrin. The toxicity of allethrin to pupae of the common house mosquito
(Cuex Pipiens var. pallens Coquillett) when applied in water emulsion was
approximately 10 times that of ethythrin. From the test results of a 1:2
mixture of allethrin and ethythrin it was concluded that these two toxicants
act similarly on mosquito pupae.
Matsui (12) in Japan and LaForge, Green, and Schechter at Beltsville
have synthesized an insecticidal ester named furethrin of the type of alle-
thrin but with a 2-furfuryl side chain. The procedures follow those employed
in the synthesis of allethrin with furfurylacetone as a starting material.
- 23 -
Tests on house flies by Gersdorff and Mitlin (M) show that furethrin
compares favorably with allethrin in toxicity to house flies. '0 f all com-
pounds analogous to allethrin, furethrin is the most promising. In tests
against the house fly by the turntable method furethrin (synthesized in
Beltsville) had a relative toxicity of 1.1 as compared to a toxicity of 1
for the pyrethrins. The ester made by combining natural (L.-trans) chrysan-
themum monocarboxylic acid with furethrolone had a relative toxicity of 1.9.
Both products had high knockdown value.
Gersdorff and Mitlin (_7) tested the insecticidal value of certain
allethrin analogs to house flies. Five substituted cyclopentenolones were
acylated with a mixture of 11s and trans l-chrysanthemum monocarboxylic
acids and the purified esters dissolved in refined kerosene for testing by
the Campbell turntable method. Two compounds, each with one chlorine atom
introduced into the allyl side chain characteristic of allethrin, were
one and one-half times as toxic as pyrethrins. No difference in toxicity
was demonstrated whether the attachment was on the second or third carbon
atom. A compound with a triple bond in the side chain (2-butynyl) of the
cyclopentenolone component was about three-fourths as toxic as pyrethrins.
A compound with a chlorine atom introduced at the third carbon atom in the
2-butenyl side chain was one-fifth as toxic as pyrethrins. A compound with
an allyl side chain attached to the carbon atom in position 5 of the cyclo-
pentenolone nucleus as well as in position 2 was about two-fifths as toxic
LaForge et al. (.12) in 1952 reported that all allethrin type esters of
a number of cyclopropanecarboxylic acids were less toxic than allethrin to
house flies by the turntable method. The most toxic ester, that of dl-
dihydrochrysanthemum monocarboxylic acid, was as toxic as natural pyrethrins.
Since the 1-trans-acid ester was but 2 percent as toxic as the d-trans-acid
ester, configuration in the acid component is of great importance with res-
pect to toxicity. The toxicity ratio of the type I ester to the type II
ester for the allethrin-type esters of the natural d-trans-chrysanthemum acids
was 4.4 to 1, which is about the same as for pyrethrins I and II andciner-
ins I and II.
Starr et al. (;72) in1950 reported that chronic toxicity tests on white
rats showed allethrin to be nontoxic when used as a spray or incorporated
with food. The allethrin tested was a technical grade product manufactured
by the Carbide and Carbon Chemicals Corporation. A diet containing 0.2 per-
cent of allethrin had no noticeable harmful effect on rats or their offspring
over a period of 24 weeks and at that time control and experimental rats were
approximately the same size. Inhalation of 1 percent allethrin aerosol sprays
in large amounts did no apparent damage to rats during 22 weeks' exposure,
30 minutes per day, 6 days per week. The rate of growth of new-born rats
subjected to the treatment was the same as the control group. In none of
the experimental animals was any abnormality found which could be correlated
with the application of allethrin.
- 2-4 -
At the June 1950 meeting of the Chemical Specialties Manufacturers
Association, Inc., Starr et al. (173) presented additional data on the
toxicity of allethrin to rats. After feeding for 41 weeks on dog-food
containing 0.2 percent of allethrin (dosage approximately 200 7:g./kg. per
day) rats were in good condition with body weight equal to controls.
All female rats gave birth to at least two normal litters. In aerosol
inhalation tests the rats were sprayed with 800 g. per 1000 cu. ft. and
exposed 30 minutes per day six days a week in their regular cages.
During a period of 39 weeks none of the experimental rats including 40
new born rats were harmed by the aerosol which contained 1 percent of
allethrin, 9 percent of petroleum distillate (Eayol D), 45 percent of
Freon 11 and 45 percent of Freon 12. Another aerosol formula contained
1 percent of allethrin, 5 percent of sulfoxide, 4 percent of petroleum
distillate (Ultrasene), 45 percent of Freon 11 and 45 percent of Freon 12.
Eight rats were sprayed with this formula as in the other test, except
that 1600 g. per ICO0 cu. ft. were tested in addition to the C'0 g.
exposure. There were no deaths in seven weeks and weight gains were normal.
A total of 40 rats which were representative of the experimental animals ex-
posed to allethrin in the diet or aerosol were sacrificed at various times
from one to eight months after the start of the experiments. Autopsy
showed no visible damage or gross pathology in any of the internal organs.
Microscopic examination of the organs was made. In none of the experimental
animals was any abnormality found which could be correlated with the insecti-
Carpenter et al. (6) of the Mellon Institute of Industrial Research
in October 1950 reported on the comparative acute and subacute toxicities
of allethrin and pyrethrins.
Two separate inhalation studies on aerosols containing 1 percent by
weight of allethrin or of pyrethrins, 9 percent of peanut oil and 90 percent
of Freon 12 were carried out at concentrations in excess of 50 g. of total
formulation per 1000 cu. ft. of space.
In the first study laboratory-produced allethrin and the comparative
aerosols casued no detectable injurious effects on rats exposed twice daily
for 30-minute periods up to a total of 85 such periods within 67 calendar
days. In a second similar study a sample representing commercially produced
allethrin (92 percent allethrin) caused no injury to rats or dogs receiving
40 exposures, each of 30 minutes duration, within 27 calendar days.
Single 30 minute exposures of rats to concentrations of aerosols of
commercial allethrin and pyrethrins on the order of 350 times the level used
for the repeated exposures caused no visible damage, nor did they depress
weight gain duringasubsequent 14-day observation period.
A fog of commercial aLlethrin produced by a vaponefrin nebulizer was
lethal to one of 10 rats in a two-hour exposure at a concentration of 19
mg./l., and only four of 10 succumbed in a four-hour exposure to 13.8 mg./l.
These massive concentrations of allethrin are respectively 10,000 and 7,000
times the amounts that would be present in the aerosols utilized in freeing
aircraft from insects. The extreme viscosity of an F4 percent pTethrin
concentrate and its unavailability made comparison by this method impossible.
The single dose acute oral LD-50's of commercial allethrin for
rodents fed 20-percent dilutions in deodorized kerosene are as follows:
mice 0.48, rats 0.92, and rabbits 4.29 g./kg. Two different samples of
purified pyrethrins, 20 percent in petroleum distillate, gave LD-50 values
of 0.82 and 1.87 g./kg. for rats.
The LD-50 of undiluted commercial allethrin for rabbits by the per-
cutaneous route is 11.2 ml./kg. Dilution in deodorized kerosene markedly
increases toxicity by skin penetration, but dimethyl phthalate appears not
to aid penetration.
Undiluted commercial allethrin and dilutions in deodoriz-ed kerosene
are harmless to rabbit eyes, but they cause moderate erythema of the clipped
skin of the rabbit belly when applied in single or repeated applications.
Drill cloth impregnated with this allethrin at the rate of 4 g. per square
foot caused marked erythema of the hair-free trujik of rabbits when worn for
three days. Subsequently these reactions subsided even though the impreg-
nated bands were reapplied twice each week during a 21-day period of wear.
No systemic injury, as judged by weight changes, resulted, and all skin
reactions had subsided in this interval.
Guinea pigs could not be sensitized by a course of e*ght intracutaneous
injections of a 0.1-percent dispersion of all]ethrin in 3.3-percent -propylene
glycol in isotonic sodium chloride solution followed by a 21-day incubation
period before retest.
Carpenter et al. concluded that commercial allethrin is of the same
relative order of toxicity as pyrethrins and that it may be used safely as
an insecticide in sprays and aerosols.
Lehman (115) of the Food and Drug Administration in 1951 stated that
the acute toxicity of allethrin to the rat (approximate LD-50 mg./kg.) was
680 and that of the pyrethrins was 200. In these tests the dosages were
administered by stomach tube to fasted animals. Allethrin causes tremors
and convulsions. The onset of the sFyr-ptoms of poisoning is within 30 min-
utes, the duration 6 hours. Fatalities appear to be rare 24 hours after
poisoning. Death is due to respiratory paralysis.
Ambrose and Robbins (43) of the Western Regional Research Laboratory
of the U. S. Department of Agriculture have reported a study of the com-
parative toxicity of pyrethrins and allethrin.
Purified pyrethrins containing 86.2 percent total pyrethrins and syn-
thetic allethrin containing 93.6 percent allethrin administered gastrically
or subcutaneously to rats in doses of 2.6 and 1.6 gm./kg., respectively,
produced no toxic reactions. When rubbed into the skin of rats in amounts
of 50 mg. daily for 30 days, they produced no local reactions. On albino
guinea pigs and on the anterior cubital surface of three humans, purified
pyrethrins or allethrin produced no signs of local irritation. With less
pure allethrin some transitory skin irritation was observed. Albino guinea
pigs were not sensitized by topical application or intracutaneous injection
of purified allethrin. The effect of prolonged oral ingestion of one sample
- 26 -
of commercial allethrin and a purified sample of commercial allethrin,
assaying 72.4 and 92 percent allethrin, respectively, was studied in rats on
diets containing 78, 156, 312, 625, 1225, 2500 and 5000 ppm of the respective
allethrin samples. Rats on the diet containing 5000 ppm commercial alle-
thrin showed a slight decrease in growth as compared with rats on the diet
containing the same concentration of purified allethrins. Hematological
findings on rats on the various dietary levels of the two allethrin sar.ples
were indistinguishable from those of the controls. From these preliminary
observations it is concluded that purified allethrin is no more toxic than
purified pyrethrins. The toxic reaction observed after topical application
or after prolonged oral ingestion is undoubtedly due to impurities. More
extensive studies on chronic toxicity are in progress.
Lehman (116) has expressed the opinion that the pyrethrins in combin-
ation with anr of the three activators, piperonyl butoxide, n-propyl some
and MKG 264 appear to be among the safest of insecticides. "We have yet to
demonstrate adverse effects in our animals on chronic feeding experiments
at levels considerably above what might be expected as contaminants of food
when these materials are properly used. Allethrin is showing every indication
of being in the same category, toxicologically, as the natural pyrethrins.
The dermal and acute oral toxicities, and the preliminary chronic feeding
data coincide very well with our results on the natural products."
CLASSIFICATION OF INSECTS AGAINST WHICH ALLETHRIN
HAS BEEN TESTED
The literature records the results of tests of allethrin against 67
identified species of insects and other arthropods belonging to 60 genera,
37 families and 10 orders. In addition allethrin has been tried against
many insects unidentified as to species such as ants, lice, and mosquitoes.
In the following summary of these tests the families and genera of
insects are placed alphabetically under the orders which are arranged
according to increasing complexity of structure from Orthoptera to Hymenoptera.
Blattella germanica (L.), the German cockroach
Allethrin at 100 and 200 mg. per 100 ml. was inferior to pyrethrins in
knockdown in 1 hour and mortality in 24 hours.--Stoddard and Dove (177).
Allethrin was inferior to pyrethrins. In tests on roaches the addition
of piperonyl butoxide, MGK 264 and two homologs thereof to allethrin increased
the kill.--Moore (134).
- 27 -
When tested in oil solution by the direct spray method allethrin was
1/2 as effective as the pyrethrins in knockdown and kill. When tested by
the settling mist method at concentrations of 0.10 and 0.20 percent,
allethrin was nearly equivalent to pyrethrins in knockdown and kill.--Nash
When tested in Deobase solution by the settling mist method allethrin
was slower in knockdown than pyrethrins and caused 0.7 to 0.9 as much
mortality of female roaches in 48 hours.--Granett .et al. (86).
Periplaneta americana (L.), the American cockroach
An aerosol containing 1 percent of allethrin applied at a dosage of
35 g./1000 cu. ft. killed no adult females in 5 days and only 12 percent of
large nymphs; pyrethrins killed 42 percent of the adult females and 18 percent
of Tne large nymphs. The roaches were confined in a pen on the floor of a
1eet-Grady chlaber.-Fales et al. (70'.
Allethrin was inferior to pyrethrins.--Moore (;1_).
By the injection method the approximate LD-50 for female nymphs was
3.25 micrograms per gram for allethrin, and 1.375 micrograms per gram for
pyrethrins indicating the natural material to be about 2.4 times as toxic
as allethrin when tested in this way.--Bishopp (48).
When tested in Deobase solution by the settling mist method allethrin
was 1/4 to 1/6 as toxic as pyrethrins to female roaches; 0.2 percent pyre-
thrins caused the same knockdown in 30 minutes and the same kill in 4 days
as 1.2 percent allethrin.--Granett et al. (86).
Hercinothris femoralis (Reut.), the banded greenhouse thrips
In greenhouse tests aerosols of allethrin and of pyrethrins gave
equally good control.--Roark (1492).
Aleurocanthus wolumi Ashby, the citrus blackfly
In laboratory tests allethrin in Deobase was slightly superior to a
similar solution of pyrethrins.--Bishopp (48).
Aphs fabae Scop., the bean aphid
Allethrin at the rate of 0.06 pound per 100 gallons of water plus an
equal quantity of Dreft killed 100 percent of the aphids; pyrethrins did
likewise. Dreft alone killed only 2 percent of the aphids.--Bishopp (8).
In laboratory spraying tests against adult apterous viviparous
parthogenetic females pyrethrins were about 14 times as toxic as allethrin.
--Elliott et .a. (66).
Aphis yossypii Glov., the cotton aphid
In tests against the cotton aphid 1 and 2 percent allethrin dusts
caIud about the same mortality as 0.1 and 0.2 percent pyrethrins dusts,
that is 10 to 14 percent. Even at 10 percent allethrin killed only 53.3
percent. When tested in a gre r.house as liquefied gas aerosols containing
1 percent of toxicant, pyrethrins were slightly superior to allethrin.
When tested in the laboratory in the form of dusts by a modification
of the settling tower method pyrethrins were better than allethrin against
nymphs.--Stoddard and Dove. (177).
Brevicoryne bras sicae (L.), the cabbage aphid
Allethrin dust was inferior to pyrethrins dust.--Roark (142).
Macrosiphoniella sanborni (Gill.), the chrysanthemum aphid
When tested in a greenhouse as liquefied gas aerosols containing 1
percent of toxicant pyr thrins were slightly superior to allethrin.--
MacrosiDhum pisi (Kltb.), the pea aphid
Allethrin dust was 1/2 as effective as pyrethrins dust; allethrin
spray was less effective than pyrethrins spray.--Bishopp (48.).
Pyrethrin dusts were from 2 to 3.4 times more effective than allethrin
against 2-day old nymphs at 3 dosage levels. Liquid dosages of 0.0125
percent v/v of both materials were about equally effective. At intermediate
and low mortality levels allethrin was less effective.--Bottger and Yering-
In laboratory tests allethrin and p:.'rethrins in the form of pyrophyllite
dusts and aoueous emulsions (made by adding an acetone solution to water)
cnml'ared as follows on the basis of 50-percent mortality values:
pyrethrins 14. x allethrin (dusts)
pyrethrins 3.8 x allethrin (dips) --Bottger (5).
Macrosiphumn solanifolii (Ashm.), the potato aphid
In laboratory spraying tests in England allethrin was only 1/16 as
toxic as pyrethrins.--Elliott et al. (66).
W7u solani (Kltb.), foxglove aphid
In greenhouse tests aerosols of allethrin and of pyrethrins were
equally effective.-- Roark (19).
zus persicae (Sulz.), the green peach aphid
Allethrin dust was inferior to pyrethrins dust.--Roark (149).
Aphis rosarunum Kltb.,
Allethrin at the rate of 0.06 pounds per 100 gallons of water killed
100 percent of the aphids; pyrethrins at the same strength killed 97 percent.
Dreft (used as a wetting agent at 0.06 pound per 100 gallons of water) alone
killed 37 percent of the aphids.--Bishopp (48).
Circulifer tenellus (Baker), the beet leafhopper
Allethrin dust was inferior to pyrethrins dust.--Roark (149).
Macrosteles divisus (Uhl.), the six-spotted leafhopper
Emulsions and dusts of pyrethrins were more effective than those of
In greenhouse tests of aerosols, allethrin proved inferior to pyrethrins.--
Phenacoccus gossypii T. & C., the Mexican mealybug
Allethrin, 0.125 pound per 100 gallons of water plus 0.08 pound of Dreft
killed 84 percent, pyrethrins 92 percent, and Dreft alone 14 percent. When
tested as liquefied gas aerosols containing 1 percent of toxicant in a green-
house Dyrethrins were slightly superior to allethrin.--Bishopp (48).
Anasa tristis (Deg.), the squash bug
In the form of water emulsion sprays pyrethrins were 3 times as effective
as allethrin and a dust containing 0.23 percent of pyrethrins killed 46 percert,
whereas a dust containing 0./+6 percent of allethrin killed 21 percent.--Moore (13).
Pyrethrin dust was better than allethrin dust against nymphs and adults.
--Stoddard and Dove (177).
Oncopeltus fasciatus (Dall.), the large milkweed bug
When tested as dusts allethrin was 1/2 as effective as pyrethrins:
when tested as sprays allethrin was twice as effective as pyrethrins.--Bishopp(48).
Pyrethrin dusts were twice as effective as allethrin against 3rd instar
nymphs. When tested as 0.0125-percent sprays allethrin was twice as effective
as pyrethrins and when the dosage was reduced to 0.0055 in the allethrin it
was 5 times more effective than pyrethrins.--Bottger and Yerington (52).
In laboratory tests allethrin and pyrethrins in the form of aqueous
emulsions (made by adding an acetone solution to water) compared as follows
on the basis of 50 percent mortality values.
allethrin 2.5 x pyrethrins (sprays) -Bottger (50).
Lygus oblineatus (Say), the tarnished plant bug
In greenhouse tests allethrin spray (32 ounces of 4 percent solution
per 100 gallons equivalent to 0.01-percent concentration) was ineffective; the
control 96 hours after spraying was 25 percent.--Zia-Din ( ).
Murgantia histrionica (Hahn), the harlequin bug
When tested in the laboratory in the form of dusts by a modification of
the settling tower method pyrethrins were better than allethrin.-Stoddard
and Dove (177).
Haematopinus eurysternus (Nitx.), the short-nosed cattle louse
When 0.05-percent sprays were applied to cattle infested with the short-
nosed louse, motile forms were killed by both pyrethrins and allethrin.
Pediculus humanus corporis Deg., the body louse
Laboratory tests indicated that body lice in Korea which were highly
resistant to DDT were about as susceptible to allethrin as normal laboratory
colony lice at Orlando, Florida. In beaker tests (cloth impregnation)
0.05-percent allethrin caused 100 percent mortality after 24 'hours exposure;
0.01-percent caused 62 percent mortality. In laboratory tests on residual
effectiveness, the pyrethrin 2,4-dinitroanisole formulations appeared some-
what more effective than similar formulation containing allethrin in place of
2,4-dinitroanisole. Six pyrethrin and allethrin powder formulations caused
good reductions of lice in field tests after one treatment and almost complete
eradication of lice after three treatments. All six formulas appeared equally
effective under the conditions in which the tests were made. Pyrethrins and
allethrin at a concentration of 0.1 percent caused 100 percent mortality of lice
in 24 hours. Both caused complete knockdown at a concentration of 0.05 percent,
but the pyrethrins did not give complete mortality in 24 hours. At a concen-
tration of 0.025 percent neither material caused complete knockdown or kill in
24 hours. In recent tests with the non-resistant strain of lice at the Orlando,
Florida laboratory, a concentration of 0.05 percent of either material generally
caused complete knockdown but rather low mortalities in 24 hours. It would
appear, therefore, that there is little difference in the susceptibility of
normal and DDT-resistant Korean strains of body lice to allethrin and pyrethrins.
LasodMa serricorne (F.), the cigarette beetle
A spray containing allethrin was inferior to one containing pyrethrins.
Acalymma vittata (F.), the striped cucumber beetle
See under Diabrotica.--Stoddard and Dove (177).
Alti ambies (Lec.), the alder flea beetle
Allethrin was more effective than pyrethrins both in dusts and in sprays.
Allethrin dust was 17 percent more toxic than pyrethrins dust. Allethrin
spray 0.05 percent v/v killed 29 percent of the test insects, whereas
pyrethrins at 0.10 percent v/v killed none.--Bottger and Yerington (52).
Diabrotica undecimpunctata howardi Barb., the spotted cucumber beetle
When tested in the form of dust in the laboratory by a modification of
the settling tower method allethrin proved inferior to pyrethrins.--Stoddard
and Dove (177).
In cage tests of impregnated dusts a dust conti :'ir,4- 0.23 percent of
pyrethrins was better than one containing 0.46 percent of alletnrin.--Moore (L.?).
Leptinotarsa deccnineictL (Say), the Colorado potato beetle
'Then tested in the laboratory in the form of dusts by a modification of
the settling tower method pyrethrins were better than allethrin.--Stc.,ddard and
ht.d:' n cochleariae (F.), the mustard beetle
In laboratory spraying tests pyrethrins were 5 times as toxic as allethrin
to adult beetles.--Elliott et a. (66).
Epilachjna varivestis Muls., the Mexican bean beetle
Uhen tested in the laboratory in the form of dusts by a modification of
the settling tower method pyrethrins were better than allethrin agar:st adults
and larvae.--Stoddard and Dove (177).
^ryzczephilus surinamensis ( LJ), the saw-toothed grain beetle
In laboratory ;Traying tests on adult beetles pyrethrins were about
2 1/2 times as toxic as allethrin.--Elliott et al, (66).
Listroderes costiros rjs obliquus Klug, the vegetable weevil
A dust containing allethrin was inferior to a p:.rethrins dust.--Roark ( .)).
Sitrophilus oryza (1.), the rice weevil
Adult weevils were immersed for 5 minutes in 0.5-percent emulsions of
allethrin and pyrethrins at 20 C. Allethrin caused less mortality than
pyTrethrins 24 hours after treatment, but more mortality at 48 hours and 72
hours after treatment.--Sakai et al. (153).
Attagenus piceus (Oliv.), the black carpet beetle
Beetle larvae were exposed to cloth impregnated with acetone solutions of
toxicants. Allethrin at 5 mg./sq. ft. produced slightly less knockdown but
higher mortality and a longer residual action than pyrethrins. At 15 mg./sc.
ft. allethrin exhibited about the same knockdown, slightly lower mortality and
longer residual effectiveness than p.,Trthrins. Pier'enyl butoxide and n-propyl
some increased the knockdown of allethrin but not the mortality.--Bishopp (48).
Popillia japonica Newm., the Japanese beetle
When tested in the laboratory in the form of dusts by a modification of
the settling tower method pyrethrins were superior to allethrin.--Stoddard ani
Tribolium confusum Duv., the confused flour beetle
By the glass plate method residues of allethrin and pyrethrins caused
equal mortality after 12 days contact and one synergist sulfoxidee) greatly
increased the kill with allethrin.--Bishopp (48).
Deposits of allethrin on glass plates paralyzed adult beetles less rapidly
than did deposits of pyrethrins and the beetles recovered much more rapidly and
completely than those that had been exposed to the pyrethrins.--Stoddard and
Sprays containing 0.5 percent pyrethrum or allethrin are recommended by
the Bureau of Entomology and Plant Cuarantine for combating insects in empty
grain bins, These sprays should be applied at the rate of 2 gallons per 1,000
square feet of wall or floor surface.--U. S. Dept. Agr. (184).
Plutella maculipennis (Curt.), the diamondback moth
In laboratory spraying tests in England against final instar larvae
allethrin was nearly twice as effective as pyrethins.--Elliott et al. (66).
During the spring of 1950 natural pyrethrum powder and allethrin, were
compared in the laboratory and in field plots in South Carolina. In general,
allethrin dusts proved less toxic than those of similar pyrethrin content.
Higher dosages of allethrin, however, showed considerable promise. In a small
field test, a 1-percent allethrin dust was about as effective as a 0.3-percent
allethrin dust against a mixed infestation of the cabbage looper, the imported
cabbageworm, and the diamondback moth.--Reid and Cuthbert (147).
Papilio polvxenes F.
iEmulsions and dusts of pyrethrins were more effective than those of
Alabama argillacea (Hbn.), the cotton leafworm
When tested against the cotton leafworm as 1- and 2-percent dusts at
10 pounds per acre allethrin showed 5 to 15 percent kill while pyrethrins
at 0.5 percent gave a 25 percent kill.--Bishopp (48).
Pseudaletia unipuncta (Haw.), the armyworm
When tested as dusts allethrin was more effective than pyrethrins, but
in the form of sprays there was no difference.--Bishopp (j).
At low and intermediate levels allethrin dust was 40 and 10 percent
respectively more toxic than pyrethrins; at high levels pyrethrins were 31
percent more effective than allethrin. As sprays allethrin and pyrethrins
exhibited similar toxicity.--Bottger and Yerington (5).
In laboratory tests allethrin and pyrethrins in the form of pyrophyllite
dusts and aqueous emulsions (made by adding an acetone solution to water)
compared as follows on the basis of 50-percent mortality values:
pyrethrins = 2.8 x allethrin (dusts)
pyrethrins =10.9 x allethrin (sprays) --Bottger (50)
Heliothis armigera (Hbn.) the corn earworm
When tested in the laboratory in the form of dusts by a modification of
the settling tower method pyrethrins were better than allethrin.--Stoddard and
In injection tests in California in which the toxicants were dissolved
in USP mineral oil, Saybolt viscosity 145 to 155 seconds, 0.4 percent of
allethrin plus 2 percent of MGK 264 was inferior to 0.1 percent of pyrethrins
plus 2 percent of the same synergist. However, both allethrin and pyrethrum
mixtures gave poor control in these tests.--Anderson et al. (45).
Trichoplusia ni (Hbn.), the cabbage looper
Emulsions and dusts of pyrethrins were more effective than those of
See also under Plutella maculipennis.--Reid and Cuthbert (147).
Ephestia eleutella (Hbn.), the tobacco moth
An oil spray containing 0.2 percent of allethrin killed as many moths as
a pyrethrins-oil spray.--Roark (49).
Pieris rapae (L.), the imported cabbage worm
Emulsions and dusts of pyrethrins were more effective than those of
See also under Plutella maculipennis.--Reid and Cuthbert (U2).
Diaphania nitidalis (Stoll), the pickleworm
Allethrin dust was inferior to pyrethrins dust.--Roark (149).
Phlyctaenia rubigalis (Guen.), the celery leaf tier
Allethrin was 1/4 as effective as pyrethrins when tested as dusts, but
was 10 times as effective when tested as sprays.--Bishopp (48).
Against 3rd instar celery leaf tier larvae pyrethrins sprays were 27.6
times as toxic as allethrin sprays and when tested as dusts pyrethrins were
13 times as toxic as allethrin.--Bottger and Mayer (51).
Pyrethrins dust was about 4 1/2 times as effective as allethrin dust
against 3rd instar larvae, but allethrin was roughly 10 times more effective
than pyrethrins when tested as sprays.--Bottger and Yerington (52).
Pyrausta nubilalis (Hbn.), the European corn borer
Allethrin at 0.5 ounce for 100 gallons of water caused 100 percent
mortality of newly hatched larvae. At 1/8 ounce the mortality was 33.7 percent.
Pyrethrins in the form of powdered pyrethrum flowers at 1/100 pound per 100
gallons water gave a kill of 100 percent and at 1/2 this dosage the kill was
23 percent. Pyrethrins were thus about 3 times as toxic to young corn borers
as allethrin. In these tests the toxicity of allethrin was increased as much
as 8 fold with the addition of various synergists.--Bishopp (48).
Emulsions and dusts of pyrethrins were more effective than those of allethrin
against 3rd and 5th instar larvae.--Moore (l2).
Protoparce sexta (Johan.), the tobacco hornworm
Allethrin dust was inferior to pyrethrins dust.--Roark (U9).
I"*m-l.Ir \$ umirjnimum Buckl., the little black ant
Ants were exposed for 30 minutes on pads treated with insecticides.
When the pads were aged 8 dayt; after treatment yyrethrins caused I percent
mortality as compared to 31 percent for allethrjjn. The addition of pi-erori.l
butoxide or n-propyl some did not materially improve the effectiveness of
either product. When the pads were aged only one day the mortality at the 418
hour reading was increased to some extent by the addition of these synergists.
DI V ERA
Agd aegyti (L.), the yellow-fever mosquito
Tests with 0.1 and 0.2-percent solutions of allethrin and pyrethrins
alone applied as space sprays showed Jallethrin to be slightly less effective.
The addition of 2 percent of piperonyl butoxide materially stepped up the
action of allethrin but did not enhance that of the pyrethrins.--Bishopp (48).
Against 3rd instar larvae allethrin was approximately 1/3 as toxic as
pyrethrins at the LD-50 level; 0.19 ppm as compared to 0.059 ppm. The addition
of sulfoxide (5 parts) or piperonyl butoxide (5 parts) to one part of allethrin
did not enhance its toxicity whereas these synergists did slightly raise the
toxicity of pyrethrins.--Grnnett et al. (86).
Allethrin in sprays (1 mg./ml.) at a dosage of 55.56 ml./l000 cu. ft.
killed 100 percent of the males and 99 percent of the females in 1 day;
pyrethrins (0.2 mg./ml.) killed 82 percent of the males and 62 percent of the
females.--Fales et al. (70.).
Aedes spp., flood-water mosquitoes
Allethrin and pyrethrins were applied to cp.r'es at the rate of 0.5 mg.
per :'. ft. and 24 hours later mosquitoes were introduced and exposed for 2
minutes. Pyrethrins gave a mortality of 74 percent and two srmples of allethrin
58 and 144 percent. When piperonyl butoxide was added to each product all the
mosquitoes -"xposed 2 hours in cages treated with pyre-thrins were killed; when
exposed in cages treated with allethrin the kills were 63 and 45 percent.
.'.ii~i,]" ,'iuadrJmcudlti nSay, the common malaria mos,'-uito
All]ethrin spray, I mr./ml. at a do.-'sje of 9.26 ml./l000 cu. ft. killed
65 percent of the males and 16 percent of the females in I day; pyrethrins at
0.2 mg./ml. at the same dosage killed 73 percent of the males and 43 percent
of the females. At a dosage of 55.56 ml./l000 cu. ft. allethrin killed 100
percent of the males and 99 percent of the females; pyrethrins killed (at a
dosage of 9.26 ml./lCOO cu. ft.) 67 percent of the males andr 38 percent of
the females.--Fales et al. (70).
Cu piriens var. palLcns Coq.
In Japan Nagasawa et al. (13P) reported that mosquito incense containing
allethrin was about 1.5 times as effective as a similar pyrethrin incense to
adults. When applied in oil solution to the pupae allethrin was about 0.06
tinifs as toxic as pyrethrins at LD-99.87.--Nagasawa et al1. (=_7).
Fales et al. (9) reported that in Peet-Grady tests with allethrin on
free-flying laboratory reared Aedes eef',Trti, ArnhT u, ct_ and
Culex pipiens the Aedes were the least resistant and the Culex were the most
resistant. 'Then the mortality figures for Aedes females were plotted, it was
found that the IC-50 of aliethrin was eight times that of the pyrethrins.
With Atr.nopheles twice and with Culex approximately five and one-half times the
amount of allethrin was required. Against male Aed.es, the amount allethrin
required was again eight times that of 1j.-rethrins. With Ar'' the materials
gave nearly equal performances. With Culex the lowest concentration of allethrin
(3.2 mg./ml.) gave approximately the same results as the highest concentration
of pyrethrins (1.6 mg./ml.).
Drosophila nelanc'raztpr Mg., the ponace fly
Sakai et L. (1i2) tested the action of insecticides on the "vestigial
form" of the pomace fly by immersing the insects into emulsions of the insecti-
cides for 2 minutes at 20 C. and determining the mortality after 30 minutes.
In experiments on insecticide alone, pyrethrins were markedly more toxic than
the other insecticides, but allethrin was more toxic than the other synthetic
insecticides as regards KID values. On the basis of the LD, the toxicities
of each contact insecticide were expressed in order of effectiveness as follows,
1) pyrethrins, 2) allethrin, 3) rotenone, 4) gamma BHC, 5) TEPP, 6) pp'DDT,
7) op'DDT, 8) parathion, 9) O,O-diethyl-O-para-nitrophenylphosphate, 10) dieldrin,
11) nicotine, 12) aldrin and 1.3) toxaphene. Although chlordane was tested in
the present investigation, it was not toxic against the pomace fly. Syrmer.-rism
was exhibited by a mixture of allethrin and BHC and antagonism by allethrin
plus rotenone, and allethrin plus pyrethrins.
Melophagus ovinus (L.), the sheep tick
Sprays of pyrethrins were superior to those of allethrin.--Roark (149).
Bradvsia fenestralis (Zett.)
Megaselia agarici (Lint.)
Adults of both species of mushroom flies appeared more susceptible to
[,Trethrins dust than to allethrin dust.--Roark (149).
1i ,cci d crnstici L., the house fly
When applied as space sprays against house flies natural pyrethrins
were slightly more effective than allethrin at 0.1 percent, but at 0.2 percent
the reverse was true. '.'.hr-n piperonyl butoxide was added to allethrin in a
5:1 ratio there was a 34 percent increase in toxicity as compared with a 54
percent increase when the pyrethrins were used. Cages were dipped in acetone
solution containing 0.1 percent of various toxiceants and after 24 hours flies
were introduced. Allethrin killed 74 percent and pyrethrins 47 percent of the
flies. When 1 percent of piperonyl butoxide was added the toxicity of the
pyrethrins was increased to 92 percent whereas the toxicity of allethrin remained
When tested by the Peet-Grady method allethrin was less effective than
pyrethrins at low concentrations (below approximately 125 mg./l00 ml.) but
was more effective at concentrations above this. To give 50 percent kill of
the house flies 145 mg./l00 ml. of allethrin were required as compared to
165 mg./l00 ml. of pyrethrins. An allethrin residue on a glass plate was more
effective in knockdown and kill than an equal residue of pyrethrins. A 1 percent
allethrin aerosol was almost, but not quite, the equivalent of a 1 percent
pyrethrin aerosol.--Nash (13.2).
Blackith (k49) in 1951 stated that in his experience and in that of Elliott
et al., allethrin gives parallel regression lines with the natural extracts.
In tests with sprays containing 1 mg. of toxicant per milliliter of
deodorized kerosene allethrin and pyrethrins rave the same kill (25 percent in
1 day) and essentially the same knockdown in 10 minutes (87 and 84 percent,
respectively). In tests with aerosols (89 percent of Freon 12, 6 percent of
methylene chloride, 4 percent of deodorized kerosene and 1 percent of toxicant)
applied at a dosage of 4.63 grams per 1000 cu. ft. allethrin and pyrethrins
gave the same kill (32 percent in 1 day) and almost the same knockdown in 10
minutes (69 and 73 percent, respectively).--Fales et &l. (270).
When tested in aerosols allethrin is equal to pyrethrins in knockdown and
kill. The addition of 2 percent of DDT enhances the kill of both materials.
The synergistic effect of piperonyl butoxide is considerably less with allethrin
than with pyrethrins.--Moore (14).
When sprayed in 0.1-percent Deobase solution on adult flies allethrin was
superior to pyrethrins in both 10-minute knockdown and 24-hour kill. When exposed
to ultraviolet light for 5 hours (equivalent to 5 days exposure to mid-day sun)
and to heat (110F. for 24 hours and to 120F. for an additional 48 hours) allethrin
proved more stable than pyrethrins. These tests were made on mosquito larvae and
house flies. An allethrin residue of 144 mg. per sq. ft. persisted for several
months against house flies and when a synergist (piperonyl butoxide or sulfoxide)
was added the amount of residue could be reduced to 28 mg. per sq. ft.--Granett
et a ( '. ).
In tests made by the turntable method allethrin was about 3 times as
toxic as the pyrethrins.--Gersdorff (.2).
In England Crombie et al. (61) quote Psrkin and Green of the Pest
Infestation Laboratory as reporting that when allethrin and pyrethrins
were tested over the concentration range 0.05-0.4 percent w/v in odorless
distillate by a modified Peet-Grady method "Thi-re was no difference in
toxicity between the two sets of corresponding solutions either in knock-
down in 10 minutes or in kill in 24 hours."
March and Metcalf (122) in 1950 reported that resistant and nonresistant
houseflies showed approximately the same level of susceptibility to pyrethrins
and allethrin. In these tests the insecticides in acetone solution were applied
to flies with a micro-syringe. The 24-hour LD-50ts in micrograms per female
Laboratory strain Bellflower strain Pollard strain
Pyrethrins 1.0 0.94 1.6
Allethrin 0.43 0.97 0.5
On the basis of LD-50's the Bellflower strain of flies was more than 300
times as resistant to DDT as the non-resistant laboratory strain and the
Pollard strain was even more resistant. On the basis of LD-95's the Bellflower
strain was more than 1500 times as resistant to DDT as the laboratory strain.
The authors conclude that the use of space sprays or aerosols containing
pyrethrins or the equivalent represents the only satisfactory means for the
chemical control of flies resistant to both DDT and BHC.
Houseflies from a dairy near Orlando, Florida that were times as
resistant as regular flies to DDT exhibited no increased resistance to pyrethrins
plus piperonyl butoxide and allethrin plus piperonyl butoxide.--Knipling (.10).
Ouarterman (129) of the U. S. Public Health Service at the 19th Annual
Convention of the National Pest Control Association held in Boston October 30,
1951 stated that for the control of resistant flies pyrethrum with synergists
can be used successfully. Allethrin is a promising substitute for pyrethrum
in some cases but not in others.
Houseflies which were resistant to DDT in 1949 acquired increased
resistance to five additional chlorinated hydrocarbons in 1950, but little
or none to allethrin and pyrethrins.--Gilbert et al. (84).
Against resistant flies in Florida allethrin and pyrethrins plus piperonyl
butoxide were moderately effective early in 1950, but by the end of the season
none of them provided satisfactory control.--Wilson et al. (194).
Siphona irritans (L.), the horn fly
A dust containing 0.5 percent of allethrin applied at the rate of 2.3
to 2.5 ounces per animal caused 53 percent reduction in the number of horn flies
on cattle in te1ts nt (tswego, New York in A9Y). A spray of' ',mTenone i-5
caused the greatest reduction ( percent.--Ooodwin et al. (E2 .
t. r. :,_ c'f t.rr. (L.), the stable fly
To tact the residual, effectiveness of allethrin and F-',-'thrins scre n-
wire cao, s were dipped into 0.l-percent solutions of these toxicants alone
and with the addition of i percent of piperonyl butoxide. Stable flies were
introduced one day later and exposed for 24 hours. In two tests ,rethrins
avw- a 100 percent knockdown and kill with and without the synergist whereas
aliethrin alone U)v, 6 and 92 percent knockdomwns and 40 and F5 percent kills
and the mixture 87 and 82 percent knockdowns and 72 and 70 percent kills.
Additional tests with stable flies introduced 4 days after treatment indicated
that pyrethrins were much more effective than allethrin from a residual stand-
point and the addition of piperonyl butoxide did not enhance the effectiveness
of allethrin.--Bishopp (4F).
Chrysops discalis Will., the deer fly
Tabanus sonomrnensis O.S.)
) horse flies
T. runctifer O.S. )
A concentration of 1 mg. per square foot or greater was necessary to
obtain knockdown of the deerfly in less than two hours with either natural
pyrethrins or allethrin when used alone. Natural pyrethrins plus synergists
usually produced superior results to those obtained with allethrin and the
same synergist. At 0.5 rmg. per square foot of pyrethrins and 5 mg. per square
foot of synergist, piperonyl butoxide was the most effective synergist, resulting
in complete knockdown in an average of 3 minutes with either natural pyrethrins
or allethrin and a 100 percent mortality in 8 hours after an exposure of 1 1/2
minutes to the treated surfaces. Lower dosages, however, provided greatly
reduced effectiveness particularly in relation to the synthetic product.--Hoffman
and Lindquist (103).
Tabanu:. guincuevittatus Weidemann
A dust containing 0.5 percent of allethrin applied at the rate of 2.3 to
2.5 ounces per animal caused 45 percent reduction in the number of horse fli s
on cattle in tests at Cswego, New York in 1950. A spray of Pyrenone 1-10
caused the greatest reduction -93 percent.--Goodwin et al. (85).
Otobius nmirli (fr''ies), the ear tick
Allethrin was less effective than pyro'thrins in tests against spinose
ear ticks and winter ticks in wlich the ticks were dipped in acetone solution
of the insecticides.--Roark (149).
Dermacentor albipictus (Pack.), the winter tick
See under spinose ear tick.
Paratetranvchus citri (McG.), the citrus red mite
Allethrin and pyrethrins as 2-percent dusts were ineffective; as sprays
11-percent v/v dosages of both materials gave 100 percent mortality.--Bottger
and Yerington (52).
Tetranychus bimaculatus Harvey, the two spotted spider mite
Allethrin at 0.125 pounds per 100 gallons caused 56 percent dead and
moribund; twice this concentration raised the percentage to 72. The corres-
ponding figures for pyrethrins were 8 and 89 percent. These toxicants were
dispersed in water with Dreft. When tested in a greenhouse as liquefied gas
aerosols containing 1 percent of toxicant pyrethrins were slightly superior to
allethrin. A spray of allethrin was about equal to one of pyrethrins, but
allethrin dust was 1 1/2 times as effective as pyrethrins duFt.--Bishopp (8).
Allethrin dust was about 73 percent more effective than pyrethrins dust.
When tested as sprays of 0.1 percent concentration allethrin was slightly
superior to pyrethrins.--Bottger and Yerington (52).
Tetranychus sp., red spider
Against the red spider on cotton a dust containing 0.1 percent of the
toxicant in Attaclay was applied at the rate of 10 pounds per acre. The kill
after 60 hours was 19.7 percent for allethrin and 4.6 percent for pyrethrins.
The addition of piperonyl butoxide failed to increase the kill.--Bishopp (A8).
1949. An active principle of pyrethrum synthesized. Chem. and Engin.
News 27: 930. March 28.
1949. New pyrethrum-like synthetic insecticide. Pests 17(4): 32.
1949. Chemical warfare USDA. USDA 8(9): 1. April 25.
[Synthetic pyrethrum.J Editorial. Agr. Chem. 4(4): 23-24.
Insecticide synthesized. Chem. and Engin. News 27: 1942-
1943. July 4.
[Synthesizing pyrethrum.] Editorial. Agr. Chem. 4(7): 19-20.
fAllyl homolog of cinerin I.1
rAllyl homolog of cinerin I.]
2669. Sept. 19.
Soap and Sanit. Chem. 25(9):
Chem. and Engin. News 27:
1949. Flowers not necessary. Chem. and Engin. News 27: 2754. Sept. 26.
1949. Synthetic pyrethrum output in large lots approaching. Oil,
Paint, and Drug Rptr. 156(13): 5. Sept. 26.
1949. Penick synthesizes pyrethrum. Agr. Chem. 4(7): 63. July.
1949. Penick now making synthetic pyrethrins. Oil, Paint and Drug
Rptr. 156(1): 5. July 4.
1949. USI producing cinerin homolog. Soap and Sanit. Chem. 25(9):
1949. fSynthetics related to pyrethrins.] Chem. and Engin. News
27:2923. Oct. 10
1949. Active pyrethrum factor to be produced by U.S.I.
Engin. News 27: 2989. Oct. 17.
1950. U.S.I. acquires foreign rights to synthetic pyrethrum' patents.
Chem. and Engin. News 28: 941-942. March 20.
1950. Commercial production of synthetic pyrethrin. Chem. and
Engin. News 28: 1138. April 3.
1950. Kenya kaput? Chem. Ind. 66: 506-507. April.
1950. Synthetic pyrethrin. Chem. and Engin. News 28: 1234.
Aerosol dominates discussions of specialty manufacturers.
Chem. and Engin. News 28: 2170-2171. June 26.
Pyrethrum acreage in Kenya reduced sharply in 1949.
Paint and Drug Rptr. 158(5): 59. July 31.
1950. Green light. Chem. and Engin. News 28: 3857-3858. Nov. 6.
1950. Army-Navy needs. Chem. and Engin. News 28: 4442. Dec. 18.
1951. Army okays allethrin, MGK expands. Chem. and Engin. News
29: 3. Jan. 1.
1951. Prop for allethrin. Chem. Indus. Week 68(2): 11-12. Jan. 27.
1951. MCK allethrin expansion. Soap and Sanit. Chem. 27(2): 155. Feb.
Allethrin, a new insecticide. The Capital Chemist 1(3): 70-71.
1951. Pyrethrum outlook and where increased output of allethrin will
fit into the picture. Soap and Sanit. Chem. 27(3): 114-115. March.
1951. Research to application. USDA Employee News Bul. 10(7): 5.
1951. USI plans to construct allethrin unit in Baltimore. Oil, Paint
and Drug Rptr. 159(17): 5. April 23. Also in Chem. and
Engin. News 29: 1740. April 30.
1951. Bugs beware. Chem. and Engin. News 29: 1800. May 7.
1951. Allethrin attains rank as commercial chemical. Chem. and Engin.
News 29: 1946. May 14.
1951. U.S.I. to build new plant to produce allethrin. Chem. and
Engin. News 29: 2477-2478. June 18.
1951. Sprouting allethrin. Chem. Week 69(6): 30-31. Aug. 11.
1951. Seventy-five years of chemical progress A story in pictures.
fSynthesis of an active principle of pyrethrum.] Chem. and
Engin. News 29: 3340. Aug. 13.
1951. Carbide to build large allethrin plant. Chem. and Fngin. News
29: 3539. Aug. 27.
1951. Pesticides on Notice 1. Soap and Sanit. Chem. 27(12): 169. Dec.
1952. McLaughlin-Gormley-King celebrates fiftieth year. Oil, Paint
and Drug Rptr. 161(19): 5, 49. May 12.
1952. Allethrin follow-up. Chem. Week 70(22): 30. May 31.
1952. Coals to Newcastle. Chem. and Engin. News 30: 2524. June 16.
1952. Doubled, redoubled and doubled again. Chem. Week 70(26): 64-65.
1952. McLaughlin Gormley King reduces prices on allethrin. Oil, Paint
and Drug Rptr. 162(4): 5. July 28.
- 4 -
(43) Ambrose, A. M. and Robbins, D. J.
1951. Comparative toxicity of pyrethrins and allethrin. Fed. Pro-
ceedings 10(1): 276-277.
(44) American Chemical Society Chemical Trail Blazers Exhibits
1950. Exhibit No. 1. Allethrin a new synthetic insecticide.
Exhibited by Carbide and Carbon Chemicals Division of Union
Carbide and Carbon Corporation, New York 17, N. Y. Directory
of Exhibits, page 1. Sixth Natl. Chem. Exposition, Chicago,
Ill., Sept. 5-9.
(45) Anderson, L. D., Bacon, 0. G., Reynolds, H. T., and Swift, J. E.
1951. Investigations of corn earworm control on sweet corn in
California in 1950. Jour. Econ. Ent. 44: 966-971.
(46) Bailey, S. F., and Smith, L. M.
1951. Handbook of Agricultural Pest Control. Industry Publications,
Inc., New York, 191 pp.
(47) Bishopp, F. C.
1949. Synthesis of pyrethrin-like esters. U. S. Bur. Ent. and Plant
Quar. 2 pp. March 11. [Processed.]
1950. Preliminary report on allethrin. Agr. Chem. 5(8): 22, 25,
(49) Blackith, R. C.
1951. Some current problems of pyrethrum assay. Pyrethrum Post 2(3):
(50) Bottger, G. T.
1951. Comparative toxicity of allethrin and natural pyrethrins. Jour.
Econ. Ent. 44: 808.
(51) ---- and Mayer, E. L.
1951. Celery leaf tier tests with allethrin. U. S. Bur. Ent. and
Plant Ouar., Div. Control Invs. Special Rpt. No. IN4-106,
3 pp. Aug. 27. [Processed.]
(52) ---- and Yerington, A. P.
1949. Toxicity tests on samples of new synthetic pyrethrin type esters.
U. S. Bur. Ent. and Plant Quar., Div. Control Invs. Special
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(53) Brown, A. W. A.
1951. Insect control by chemicals. John Wiley & Sons, Inc., New
York. 817 pp.
(54) Calsetta, D. R., DiSanto, C., and Starr, D. F.
1952. A comparison of some synergists in liquid space spray insecticides
containing allethrin and DDT. S. B. Penick and Co. Cir. 2 pp.
(55) Campbell, I. G. M., and Harper, S. H.
1945. Experiments on the synthesis of the pyrethrins. Part I.
Synthesis of chrysanthemum monocarboxylic acid. Chem. Soc.
Jour. 1945: 283-286.
(56) Carpenter, C. P., Well, C. S., Pozzani, U. C., and Smyth, H. F., Jr.
1950. Comparative acute and subacute toxicities of allethrin and
pyrethrins. Arch. Ind. Hyg. Occupational Med. 2: 420-432.
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(57) Crombie, L., Edgar, A. J. B., Harper, S. H., Lowe, M. W., and Thompson, D.
1950. Experiments on the synthesis of the pyrethrins. Part V.
Synthesis of side-chain isomers and analogues of cinerone,
cinerolone and cinerin I. Jour. Chem. Soc. 1950: 3552.
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1949. Synthesis of cinerone, cinerolone and of cinerin I. Nature
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1950. Experiments on the synthesis of the pyrethrins. Part IV.
Synthesis of cinerone, cinerolone and cinerin I. Jour. Chem.
Soc. 1950: 1152-1160.
(60) ---- Harper, S. H., Stedman, R. E., and Thompson, D.
1951. Experiments on the synthesis of the pyrethrins. Part VI.
New syntheses of the cinerolones. Jour. Chem. Soc. 1951:
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1951. Experiments on the synthesis of the pyrethrins. Part VI.
Synthesis of trans-pyrethrone and trans-pyrethrolone. Chem.
and Ind. 13: 253-254.
(62) Cupples, H. L.
1950. Infrared spectral data: 2-(trans-2-butenyl)-4-hydroxy-3-methyl-
2-cyclopenten-l-one (liquid). Catalog of Infrared Spectro-
grams, American Petroleum Institute Research Project 44 of
the National Bureau of Standards, Serial No. 976. Feb. 28.
1950. Infrared spectra of cinerolone and synthetic trans-2-(2-butenyl)-
4-hydroxy-3-methyl-2-cyclopenten-l-one. Amer. Chem. Soc.
Jour. 72: 4522-4523.
(64) Fddy, G. W.
1951. A report or, .he effectiveness of certain insecticides against
DDT-resistant body lice in Korea. fin press.]
(65) Elliott, M.
1951. Insecticidal activity of the pyrethrins and related compounds.
Pyrethrum Post 2(3): 18-28.
(66) Elliott, M., Needham, P. H., and Potter, C.
1950. The insecticidal activity of substances related to the
pyrethrins. I. The toxicities of two synthetic pyrethrin-
like esters relative to that of the natural pyrethrins and
the significance of the results in the bioassay of closely
related compounds. Ann. Appl. Biol. 37: 490-507.
(67) Fales, J. H.
1951. Allethrin symposium synergist combinations with allethrin.
Chem. Spec. Mfrs. Assoc. Mid-year Meeting, Apr. 30 May 1,
Abstracts of Papers, pp. 31-32.
(68) ---- Bodenstein, 0. F., Nelson, R. H., and Fulton, R. A.
1951. Effect of storage on allethrin formulations. Jour. Econ. Ent.
(69) ---Bodenstein, 0. F., and Piquett, P. G.
1952. Comparison of effectiveness of allethrin and pyrethrins sprays
against adults of three species of mosquitoes. Jour. Econ.
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(70) ------ Nelson, R. H., Fulton, R. A., and Bodenstein, 0. F.
1951. Insecticidal effectiveness of sprays and aerosols containing
allethrin. Jour. Econ. Ent. 44: 23-28.
(71) ---- Nelson, R. H., Fulton, R. A., and Bodenstein, 0. F.
1951. Insecticidal effectiveness of aerosols and sprays containing
esters of synthetic cyclopentenolones with natural chrysan-
themum monocarboxylic acid. Jour. Econ. Ent. 44: 250-253.
(72) Feinstein, L.
1952. A new reaction and color test for allethrin and pyrethrins.
Science 115: 245-246.
(73) Fleck, E. E.
1952. rhe chemistry of some of the new pesticides. Bul. Amer. Soc.
Hospital Pharmacists 9(3): 174-178. May-June.
(74) Frear, D. E. H.
1952. Pesticide Handbook 1952. College Sci. Publishers, State College,
Penna. 176 pp.
(75) Galley, R. A. E.
1950. Whither insecticides? Chem. and Ind. 4: 73-74.
(76) Gersdorff, W. A.
1949. Toxicity to house flies of synthetic compounds of the pyrethrin
type in relation to chemical structure. Jour. Econ. Ent.
1949. Toxicity to house flies of new synthetic pyrethroid. Soap and
Sanit. Chem. 25(11): 129-131, 139.
(78) Gersdorff, W. A., and Mitlin, N.
1951. Relative toxicity of allethrin analogs to house flies. Jour.
Econ. Ent. 44: 70-73.
(79) ------ and Mitlin, N.
1952. A bioassay of some stereoisomneric constituents of allethrin.
(80) ------ and Mitlin, N.
Relative toxicity of furethrin, its natural acid isomer, and
pyrethrins to house flies. fin press.]
(81) --- Nelson, R. H., and Mitlin, N.
1951. The relative effect of several pyrethrum synergists in fly
sprays containing allethrin. Jour. Econ. Ent. 44: 921-927.
(82) ---- Nelson, R. H., and Mitlin, N.
1952. A comparison of the effects of sulfoxide and 3,41-methylene-
dioxybenzyl jL-propyl ether in pyrethrum and allethrin mixtures
as housefly sprays. Tin press.]
(83) Gertler, S. I., Gersdorff, W. A., and Mitlin, N.
1952. Preliminary tests with certain m-nitrobenzamides for synergistic
action in allethrin fly sprays. U. S. Bur. Ent. and Plant
Quar. E-837, 3 PP. rProcessed.]
(84) Gilbert, I. H., Couch, M. D., and McDuffie, W. C.
1951. Development of resistance to insecticides in natural populations
of house flies. Paper presented at 63rd Ann. Meeting Amer.
Assoc. Econ. Ent., Cincinnati, Ohio. Dec. 11.
(85) Goodwin, W. J., Sloan, M. J., and Schwardt, H. H.
1952. Repellency test for horse flies and horn flies in New York State.
Jour. Econ. Ent. 45: 121-122.
(86) Granett, P., Conola, D. P., and Lembach, J. V.
1951. Laboratory tests of allethrin for stability, residual action
and toxicity. Jour. Econ. Ent. 44: 552-557.
(87) Haller, H. L.
1950. Summary of presentations in allethrin symposium. Chem. Spec.
Mfrs. Assoc. Proc. 36: 67. [Soap and Sanit. Chem. Special
1951. Summary of allethrin symposium. Chem. Spec. Mfrs. Assoc. Mid-
year Meeting April 30-May 1. Abstracts of Papers, p. 32.
1951. Problems facing the insecticide industry. Agr. Chem. 6(10):
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1952. [Insecticide names.] U. S. Bur. Ent. and Plant Quar. 5 PP.
[Processed.] Jan. 10. Also in Jour. Econ. Ent. 45: 165-
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1952. Effect of structural changes in plant insecticides and related
synthetic compounds on their toxicity to insects. First
symposium on Chemical Biological correlation, May 26-27,
1950. Sponsored by Chem.-Biol. Coordination Center Natl.
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1950. Pyrethrum outlook. Oil, Paint and Drug Rptr. 158(10): 36. 74.
(93) Haring, R. C.
1951. Allethrin symposium report of the chemical analysis committee.
Chem. Specialties Mfrs. Assoc. Mid-year Meeting April 30 -
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1951. Report of the Insecticide Division Chemical Analysis Committee.
Chem. Spec. Mfrs. Assoc. Proc. 38: 86-88.
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1949. Chemistry of the insecticidal constituents of pyrethrum flowers.
Pyrethrum Post 1(3): 9-15; (4): 10-16.
1949. A nomenclature for the pyrethrins. Chem. and Ind. 37: 636-637.
1951. Developments in insecticide chemistry; synthesis of the pyrethrins.
Sci. Progress No. 155: 449-458.
1951. Recent synthetical developments in pyrethrum chemistry.
Internatl. Cong. Crop Protect. Proc. 2: 167-181.
1951. Some aspects of pyrethrum analysis. Internatl. Cong. Crop Pro-
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1951. The chrysanthemtmcarboxylic acids. I. Preparation of the
chrysanthemic acids. Jour. Sci. Food Agr. 2: 94-100.
(101) Hewlett, P. S.
1952. Piperonyl butoxide as a constituent of heavy-oil sprays for the
control of stored product insects. II. The effect ofpip-
eronyl butoxide on the toxicity of BHC and pyrethrins to
Tribolium castaneum. Bul. Ent. Research 43: 21-32.
1952. Comparisons of insecticidal activation. Nature 169: 844. May 17.
(103) Hoffman, R. A., and Lindquist, A. W.
1949. Comparative effectiveness of several synergists with natural
and synthetic pyrethrins on the deerfly. U. S. Bur. Ent. and
Plant Quar., Div. Insects Affecting Man and Animals,
Special Rpt. C-9, 12 pp. typed. Sept. 6.
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1951. The synergistic effect of piperonyl butoxide with the active
principles of pyrethrum and with allethrolone esters of
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(105) Inoue, Y., Katsuda, Y., Nishimura, A., Kitagawa, K., and Ohno, M.
1951. Studies on the synthetic pyrethrins. I. Synthesis of chrysan-
themum monocarboxylic acid. Botyu-Kagaku 16: 111-114.
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1951. Studies on the synthetic pyrethrins. III. Insecticidal effect
of synthetic pyrethroids. Botyu-Kagaku 16: 153-157.
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1950. Biological tests of allethrin with synergists. Chem. Spec. Mfrs.
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Also in Soap and Sanit. Chem. 26(8): 109, 133, 135, 137, 139.
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1951. Studies on the synthetic pyrethrins. II. Synthesis of ciner-
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(109) Klipstein, K. H.
1951. Pesticides supply outlook held favorable; lead arsenate short.
Oil, Paint and Drug Rptr. 160(15): 4, 82.
(110) Knipling, E. F.
1950. Insecticidal resistant flies and mosquitoes. Chem. Spec. Mfrs.
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1952. Ground equipment and insecticides for mosquito control. Amer.
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(112) LaForge, F. B., Gersdorff, W. A., Green, N., and Schechter, M. S.
1952. Allethrin-type esters of cyclopropanecarboxylic acids and their
relative toxicities to house flies. Jour. Org. Chem. 17: 381-389.
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1952. Dimerized cyclopentadienones from esters of allethrolone.
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(114) Langford, G. S., editor
1951. Entoma A directory of insect and plant pest control. 9th Ed.
Amer. Assoc. Econ. Entomologists, College Park, Md. 448 pp.
(115) Lehman, A. J.
1951. Chemicals in foods. A report to the Association of Food and Drug
Officials on current developments. II. Pesticides. Assoc.
Food and Drug Officials U. S. Cart. Bul. 15: 122-123.
1950. Some toxicological reasons why certain chemicals may or may not
be permitted as food additives. Assoc. Food and Drug Officials
U. S. Quart. Bul. 14(3): 82-98.
(117) McLaughlin Gormley King Company
1951. There is no shortage of MGK allethrin! [Advertisement.] Chem.
and Engin. News 29: 5189. Dec. 3.
1951. Use MGK pyrethrum with MGK allethrin. rAdvertisement.] Soap
and Sanit. Chem. 27(12): 133. Dec.
1952. A report to the industry on allethrin. Soap and Sanit. Chem.
28(6): 105-108. June. [Advertisement.]
(120) McNamee, R. W.
1950. First commercial synthesis of allyl cinerin. Carbide and Carbon
Chemicals Division, Union Carbide and Carbon Corp., 30 E. 42nd
Street, New York 17, N. Y. News Release, 3 PP., 1 fig.
March 20. [Processed.]
1950. General nature of allethrin. Chem.Spec. Mfrs. Assoc. Proc. 36:
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1950. Studies in California of insecticide-resistant flies. Chem.
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1950. Synthesis of cyclopentolones of the cinerolone type. Jour.
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1952. Furethrin. Amer. Chem. Soc. Jour. 74: 2181-2182.
F. B., Mizell, F. M., and Nichols, J. P.
Further studies on aerosol formulations with lethane and other
toxicants. Chem. Spec. Mfrs. Assoc. Proc. 37: 96-98.
TSoap and Sanit. Chem. 27(2): 125, 127. 131. 1951.
(126) Metal Hydrides Inc.
1951. For bugs: a lethal daisy chain that owes its knockout punch to
NaH. [Advertisement.] Chem. and Engin. News 29: 809. Feb. 26.
(127) Metcalf, C. L., Flint, W. P., and Metcalf, R. L.
1951. Destructive and useful insects their habits and control.
3rd Ed., McGraw-Hill Book Co., New York, 1071 pp.
(128) Miller, A. R.
1950. Eradication of vermin Use of fumigants, sprays, powders and
baits. U. S. Dept. Agr., Bur. Animal Indus., Meat Inspection
Division Memorandum No. 52, Supplement 3, Sept. 12.
1951. Eradication of vermin Use of fumigants, sprays, powders and
baits. U. S. Dept. Agr., Bur. Animal Indus., Meat Inspection
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(130) Montrose Chemical Company
1949. Synthetic pyrethrins. (Allyl homolog of Cinerin I.) fAdver-
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(131) Moore, J. B.
1950. Allethrin standardization, analysis, storage. Chem. Spec.
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Issue.] Also in Soap and Sanit. Chem. 26(8): 107-108.
Synergist "264". Chem. Spec. Mfrs. Assoc. Proc. 36: 72.
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1950. The place of allethrin in the aerosol program. Chem. Spec. Mfrs.
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1950. Relative toxicity to insects of natural pyrethrins and synthetic
allyl analog of cinerin I. Jour. Econ. Ent. 43: 207-213.
(135) Morrow, M. G.
1952. Plants that kill insects. Sci. News Letter 61(21): 330-332.
(136) Nagasawa, S., Inoue, Y., and Shibata, S.
1951. Comparison of the toxicity of allethrin and ethythrin to pupae
of the common house mosquito, and the joint action of these
two toxicants. Botyu-Kagaku 16: 169-176.
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1951. Comparison of the toxicity of pyrethrins and allethrin to
pupae of the common house mosquito (Culex pipiens var. pallens
Coquillett). Studies on the biological assay of insecticides.
XV. Botyu-Kagaku 16: 166-169.
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1951. On the knock-down effect of so-called pyrethrins and allethrin
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between 22 and 42 cents a pound. Chem. and Engin. News
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1950. Smaller imports of natural pyrethrum again direct attention to
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1951. Quick action on research results. U. S. Dept. Agr. Clip Sheet
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1952. USDA urges careful choice of residual insecticides in empty
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1949. Potent insecticide-like pyrethrum made synthetically by
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1949. Government chemists rival nature in making potent insect
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