CA1043779A - Insecticidal and acaricidal composition and process for controlling pests - Google Patents

Abstract

ABSTRACT

An insecticidal and acaricidal composition com-prising a pesticidal amount of an interacted compound of a pyrethroid with a cyclodextrin and a diluent or carrier, and a process for controlling pests using said composition.

Description

d ~3 This invention relates to an insecticidal and acaricidal composition of matter, namely a molecular compound of a pyrethroid with a cyclodextrin.
This new series of compounds exhibit improved stability to heat and light compared ~o the pyrethroids from which they are derived, while retaining insecticidal and acaricidal actions.
Pyrethroids have been widely utilized because of their superior pesticidal effect and having substantially no toxicity or very low toxicity to man and other warm-blooded animals, but on the other hand, have the defect of poor stability to heat and light, which poses a serious problem lo in storage for prolonged periods of time.
According to the present invention, there is provided a molecular compound of a pyrethroid with a cyclodextrin. Such new compounds exhibit superior stability to heat and light, and can be stored for prolonged periods of time and even when used as a fumigant exhil)it strong pesticidal activity with reduced decomposition by heat.
Furthermore, it has been found that the above ~.olecular compounds, which are presumed to consist of inclusion compounds of the pyrethroid as a guest compound and the cyclodextrin as a host crystal, have improved pesticidal effects, such as rapidity of action, as compared with the pyre- -throid alone.
The pyrethroids themselves to be used for forming ~he new compounds of this invention are known. ~xamples are pesticidal component pyrethrins of natural sources which are contained in pyrethrum obtained for example, by drying the flower of Chrysanthemum cinerariaefolium, and synthetic pesticidal component Mimics. They are known to be esters of chrysanthemic acid or esters of chrysanthemum dicarboxylic acid. Specific examples of -these natural and synthetic pyrethroids are: ;~

-2-.. ..
'' ` ~ : ' 1. Pyrethrins (natural):

Rl\ ~ ~ R2 ' (I) CO O

r Rl = methyl or methoxycarbonyl L R2 = pent-2,4-dienyl, 2-butenyl or 2-pentenyl ' ~

.

- 3 -7~
2. Mimics (synthetics):

COO ~ ... (II) R3 = methyl or iso-butenyl R4 = hydrogen or methyl R5 = allyl or propargyl A compound of formula (Il) wherein R3 is iso-butenyl, R~ is hydrogen, and R5 is allyl is well known as Allethrin.

3 ~ CoO ~ ~ CO ~ ............................... (III) ~wherein R3 and R~ are the same as defined in formula (II)]
A compound of formula (III) wherein R3 is iso-butenyl and R4 is hydrogen is well known as Tetramethrin.

:, `

RR~ COO ~ ....................................... (I~) (wherein R3 and R4 are the same as defined in formula (II), X ia methyl, allyl, propargyl, benzyl, or phenoxy, and n is 1 to 3, with the pro~
viso ~hat when n is 2, at least one ~ is methyl, and when n is 3, at least two X~s are methyl) Compounds of formula (IV) wherein R3, R4 and X respectively repre-sent isobutenyl, hydrogen, and 2,4-dimethyl 1n=2), isobutenyl, hydrogen4and 5-phenoxy (n=l), and isobutenyl, hydrogen and 4-allyl (n=l) are called respec-tively as Dimethrin, Phenothrin and Benathrin.

;

,,:,:, ,- . ~ :. ...

7~7~

COO ~ Y .................... (V) (wherein R3 and R4 are the same as defined in formula (II), ~ is -S- or -O-~ R6 is hydrogen, methyl or C2 3 alkyl~ alkenyl~ or a~ynyl~ Y is methyl~ allyl~ propargyl or benzyl~ and m is 1 or 2, with the proviso that when m is 2, at least one Y is methyl) ~-.
Compounds of the formula (V~ wherein Z is -O-, and R3, R4, R6 and Y are isobutenyl, hydrogen~ hydrogen and 2-benzyl (m=l) respectively~ and iso- ~
butenyl, hydrogen, hydrogen and (2-propargyl~ 5-methyl (m=2)) respectively~ ~ .
are wel~known respectively as Resmethrin and Proparthrin. ~ :

R4 ~ CCO ~ 2 Ym ................................. (VI~

(wherein R3~ R4, R6, Y, Z and m are the same as defined in Formulae ¦II) and ~V)) Compounds of the formula (VI) wherein Z is -O-, and R3, R4~ R6 and Y are isobutenyl~ hydrogen~ hydrogen and 2-allyl (m=l) respectively~ and iso-butenyl, hydrogen~ hydrogen and (2-propargyl (m=2)~ respectively are well known respectively as Japothrin and Furamethrin.
Other well known pyrethroids are V Cl ~ ~ r~ Barthrin COO O
X ~ ~:

~ ~ Butethrin : COO

~ .

- :: .. . ~; .

7 ~

4_allylindane-1-~ yl-chrysanthemate The cyclodextrin itself to be used for preparing the active com-pOne~t in the present invention is also known and often called cycloamylose or Schardinger dextrin. The cyclodextrin is a substance usually used, for example, as a filler in a gaschromatographic column, or a carrier of medicines.
It has a structure wherein the glucose units are cyclically bonded, and usually consists of about 6 to 8 glucose units. The method for its preparation is also well known, and for example, it can be prepared by the method disclosed in ~'Die Starke" 15~ Nr. 8, page 281 (1963), which involves causing cyclo-dextrin glycosyltransferase to act on starch or a hydrolyzed product of starchthereby to decompose and cleave the helical structure of the starch and to bond the cut ends. Furthermore~ the cyclodextrin can be prepared by the method ~ ;
disclosed in Japanese Patent Publication No. 2380/71 which comprises causing amylase of Bacillus macerans to a~ct on starch which has been lightly liquefied to a D~ of not more than 15~ The cyclodextrlns available arè9 for example7 ~-cyclodèxtrin ~cyclohexamylose)~ -cyclodext~in (cycloheptamylose), and~
cyclodextrin (cyclooctamylose). Usually, they are obtained as a mixture of these, and can be separated and purified by~ for example, fractional precipi-tation. In the present invention~ they can be used either as a mixture or as separated individual compounds.
The interacted compound of a pyrethroid with a cyclodextrin used as an active ingredient of the composition of this invention can be prepared by contacting at least one pyrethroid intimatel~ with at least one cyclodextrin in the presence of water. The water may be adhered or added water which the pyrethroid and/or cyclodextrin can contain~ but usually further water is added.
For exampleg it can be prepared by sufficiently kneading 10 to 20 parts by weight of a pyrethroid, 90 to 150 parts by weight of a cyclodextrin, : , .

7~
and 30 to 60 parts by weight of water in a kneader (further adding a small amount of water i-f dcsired, when the viscosity of the mixture increases), pouring the kneaded mixture into S times its volume of water~ and separating the precipitate by filtration and drying it to form a powdery product. The suitable temperature for kneading is about 5 to about 70 C.~ preferably -about 15 to 30 C. Usually, the kneading is carried out for about 30 minutes to about 4 hours. Alternatively, a pyrethroid is added to an aqueous solution of a cyclodextrin~ and the mixture is stirred for 30 minutes to 4 hours. Then, the stirred mixture is allowed to stand for 3 to 6 hours, followed by fil~
o tration and drying. The stirring temperature is about 5 to 70 C., preferably about 30 to about 50 C. The preferred temperature at the time of standing is room temperature or higher.
The i~teracted compound used as an active ingredient of the composi-tion of the present invention has properties clearly different from those of a mere mixture of the pyrethroid and the cyclodextrin, and the in~entors presume that it is an inclusion compound consisting of the pyrethroid as a guest compound and the cyclodextrin as a host crystal. The proportion of the pyrethroid to the cyclodextrin in the resulting interacted compound may vary over a range of 0.5 to 1.5 mols per mol of the cyclodextrin.
When an interacted compound consisting of 1 mol of allethrin as the pyrethroid per mol of the cyclodextrin is washad with cold water~ no pyrethroid is washed out, but when said interacted compo~md is extracted with diethyl etherfor 24 hours using a Soxhlet extractor, 0.5 mol of pyrethroid remains in the ~ ~;
interacted compound per m01 of the cyclodextrin, and the pyrethroid cannot be extracted further. It has not yet been clearlin what form 0.5 mol of the ex-tracted pyrethroid is included3 connected, or merely adhered in the rings and/ -or among the rings of the cyclodextrin. However, in view of the fact that when a mere mixture of the pyrethroid and the cyclodextrin is extracted similarly, substantially all of the pyrethroid is extracted, it is evident that some inter-. ~ ,:

7~
action occurs between ~he two compounds in the active ingredient used in this invention. Furthermore, in view of the fact that the cyclodextrin is known to form an inclusion compound with, for example, menthyl acetate, we presume that probably an inclusion compound consisting of the cyclodextrin as a host crystal and the pyrethroid as a guest compound is formed.
Stability to ultra~iolet rays was tested using an ultraviolet ray lamp (254 m ~) as an irradiation source on interacted compounds of this in-vention in which allethrin is present in a proportion of 0.~ mol per mol of cyclodextrin and in a proportion of 1.0 mol per mol of cyclodextrin, a mere mixture of 1 mol of cyclodextrin and 0.5 mol of allethrin ~Control No. 1), and a mere mixture of 1 mol of starch and 0.5 mol of allethrin (Control No. 2).
The results are shown in the following table 1. In the table, CD stands for cyclodextrin, and Alle stands or allethrin. The numerical values show the amounts of residue. The numerical values in the parentheses are the rate of residue in p~rcent with the value at the start being 100%.
Table 1 ~ ~ .
Sample Irradiation time . __ . I
Start 1 weeks 2 weeks 3 weeks . . . _. . . _ ~liS CD-Alle (1:0.5) 10.06% 8.15~ 6.78 invention interacted com- 10.90% (92.3) (74.8) (62.23 pound (100) CD-Alle (1:1) 16.65%12.55% 10.00~ 8.42%
interacted (100)(75.5) (60.0) (50.5) compound ~_ _ Control CD-Alle mixture 7.80 2.28 0 ~ o No. 1 (100)(29.2) (0) (0 . . . . __ _ Control 8.45 3.82 0.8 ~0~
_ _ - _ _ (100) (45-2) (~ ) (0) The irradiation source : an ultraviolet ray lamp (254 m ~) It is also seen from the results of Table 1 that interaction occurs between the cyclodextrin and the pyrethroid in the active ingredient used in ' ' ~ . ' . .

: L~3~ 7 ~

the present invention, to increase stability to ultraviolet rays, and the active ingredient used in this invention differs from a mere mixture of these two compounds. The results of the ultraviolet ray stability test and the extraction test show that the active ingredient used in this invention differs from the mere mixture, but is presumed to be the inclusion compound mentioned above.
Since, as stated above, the active ingredient used in this invention can be formed by contacting at least one pyrethroid intimately with at least one cyclodextrin in the presence of water, it will be readily understood that depending upon the formulation~ the interacted product can be formed at the time of preparing the final pesticidal composition instead of preparing the interacted product in advance and then blending it with a diluent or carrier.
For instance, in the case of a wettable powder~ the interacted product can be formed during its preparation.
The insecticidal and acaricidal composition of this invention may be in various formulations, such as a liquid, emulsifiable concentrate, wettable powder, oil, aerosol, paste, fumigant, dust, granule, tablet, or pellet.
The insecticidal and acaricidal composition of this invention con-tains various gaseous~ liquid or solid diluents or carriers, and if desired may further contain various assistants, such as a surface active agent, emulsi-fier~ dispersing agent, spreader, sticker, synergist~ antioxidant, ultraviolet absorbent~ and other insecticide.
The gaseous diluent or carrier may~ for example, be a normally gaseous diffusing agent for use in preparing aerosols. Examples of the liquid diluent or carrier are aromatic hydrocarbons such as benzene, toluene or xylene~ chlorinated aromatic or aliphatic hydrocarbons such as chlorobenzene~
dichlorobenzene~ methylene chloride, dichloroethane, trichloroethylene, tri-fluoroethylene, or benzyl chloride, aliphatic hydrocarbons such as pen~ane, hexane~ heptane~ octane or cyclohexane~ alcohols such as methanol~ ethanol~

, : `
_9_ ;

.

propanol, or butanol~ ketones such as acetone, methyl ethyl ketone, or cyclo-hexanone, and water. ~{amples of the solid diluent or carrier include mineral powders such as diatomaceous earth, talc, clay~ attapulgite, bentonite, mont-morillonite, kaolin or chalk, and organic powders such as pyrethrum powder, starch~ wood powder, leaf powder, m~crocrystalline cellulose, sugar, dextrose, dextrin, or charcoal powder.
Examples of the surface active agent or emulsifier are anionic sur-factants such as a sodium alkylbenzenesulfonate, sodium stearate, sodium lauryl sulfate, a butylamine salt of dodecylbenzenesulfonic acid, an alkyl-phenolsulfonic acid salt, or a ligninsulfonic acid salt, and nonionic surfac-fants such as an ester of tall oil, polyoxyethylene nonylphenylether, a poly-oxyethylene fatty acid ester, a polyoxyethylene alkylaryl ether, or a poly-oxyethylene ether of a polyhydric alcohol.
Examples of the dispèrsing agent are an alkylcellulose lignin sul-fite spent liquor, sodium dioctylsulfosuccinate, sodium dibutylphenylphenol disulfonate~ sodium dodecylbenzene sulfonate, sodium lauryl sulfate, poly-ethylene glycol oleate,a tall oil ester of polyethylene glycol, and p-iso-octylphenol decaethylene glycol ether.
Examples of the synergist are piperonyl butoxide, octachlorodipropyl ether, N-(2-ethylhexyl)-bicyclo(2,2,1)-hepta-5-ene-2,3-dicarbfxiimide, N-octyl-sulfoxide of isosafrole, isobornyl thiocyano-acetate, and ~ -butoxy ~I-thiocyanodiethyl ether. Pyrethroid may be cited as another insecticide.
me lnsecticidal and acaricidal composition of this invention contains a pesticidal amount of the interacted compound of a pyrethroid with a cyclo_~
dextrin in an amount of, for example, 0.5 to 100% by weight. Th~ content of this active ingredient varies depending upon~ for example~ the formulation3 the method of application, the type of the pest, and time and place of application.
The composition of this invention can be applied to pests and/or their ` habitat by various means such as spraying, atomiæing, misting, dust spraying, .

71~
fumigating, or irrigation.
The amount of the interacted compound in the ready-to-use preparation can be varied over a wide range according to the formulation. Generally~ it is about 0.01 to 50% by weight.
The insecti~idal and acaricidal composition ~f this invention is use-ful for controlling various pests such as sucking insects, biting insects, nematodes, other plant pests, sanitary pests, grain pests, agricultural pests, and forest pests. Thus, the t0rm "insecticidal and acaricidal composition"
denotes a composition ~hich is effective for controlling not only insects and acari bùt also nematodes. Specifically, the composition of this invention is useful for controlling coleopterous~ lepidopterous, hemipterous, orthopterous, isopterous and dipterous insects, and also acàri and nematodes. These pests include not only imagoes, but also the larvae, pupae, and eggs thereof.
Specific examples of these pests include flies~ mosquitoes, cockroaches~ fleas, louse, bedbugs, acari (Ornithonyssus bacoti, Dermanyssus gallinae, Ornithonyssus -sylvarrum or Acaridia), rice weevils, rust-red flour bettles, planthoppers, leafhoppers (green rice leaf-hoppers~ for example)~ thrips, common cabbageworm, aphides, lace bugs, pine caterpillars, ants, clothes moths, silver ~ish, mul-berry small weevils, tea tussock moths, tea cochlidesj smaller tea tortrixes, ~ ;
tea tortrixes, green broad-winged planthoppers,~ rice leaf beetles, and rice-plant skippers.
As previously stated, the interacted compound of a pyrethroid with a cyclodextrin is not a mere mixture of the pyrethroid and the cyclodextrin, and this was demonstrated by the test involving extraction with ~ether. In addition to this, the results of a supporting example based on thin-layer chro-matography are shown below.
An interacted compound of allethrin with ~-cyclodextrin (the molar ratio of the allethrin to the ~-cyclodextrin being 1 : 2-) was subjected to -thin-layer chromatography (solvent: acetone/water=6/4, plate: Microcrystalline ~

,,, .. , ........ ,, . . , ~.
, . ~ . .
: . . . . . .

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Cellulose tEastmann Co.) 5 x 10 cm~ color: I2 vapor~, and its Rf value and the number of spots were measured~ The results are shown in the following table.
As controls, allethrin,~ -cyclodextrin, and a ~xture of allethrin and~-cyclo-dextrin were used respectively.

. _ , _ _ Tested Compounds Number Rf value spots ~
._ __ _ _ Interacted compound of allethrin with ~-cyclo- 1 0.43 - 0.65 (yellow) dextrin .
Mere mixture of allethrin with ~-cyclodextrin 2 0.43 - 0.65 (yellow) o.97 - lf~OO (brown) . . . _ .
Allethrin 1 o.85 - 1.00 (brown) .. . . . _ ...
P_~yolodextrin 1 0.4~ - O 6; (r~

:
It is seen from the above results that the interacted eompound of allethrin with ~-cyelodextrin does not separate into two spots as in the ease with the mere mixture of allethrin with ~-eyelodextrin, but behaves as a single eompound, and that its Rf value is almost identieal with that of ~-eyelo-dextrin.
The results of the same tests eondueted on some interaeted eompoundsof a pyrethroid with ~-eyelodextrin are shown in the following table.

:`
: .
: ' :

~,13~ r~
~ ----~ ~ - -, Pyrethroids Compounds tested Number of Rf values sp~ts _ ,, . ~
Resmethrin ~-cyclodextrin 1 0.42 - o.69 (yellow3 Interacted compound 1 0.41 - o.65 (yellow) Mixture 2 0.51 - o.64 (yellow) 0.71 - 0.90 (brown) Resmethrin 1 o.69 - o.89 (brown) . , . ., _ _ ~
Furame~hrin ~-cyclodextrin 1 0.37 - o.60 (yellow) Interacted compound 1 o.36 - o.60 (yellow) Mixture 2 0.42 - 0.61 (yellow) 0.91 - 0.49 ~brown) Furamethrin 1 o. 86 - o. 98 (brown) . ~.. _ _ __~ _ , Tetramethrin ~-cyclodextrin 1 0.41 - o.63 (yellow) Interacted~;l compound 1 o.46 - o.63 (yellow)~
Mixture 2 0.43 - 0.61 (yellow) O.92 - 1.00 (brown) Tetramethrin 1 o,87 - 1.00 (brown) ~
. . . _ :
Proparthrin ~Lcyclodextrin 1 0.31 - o.65 (yellow) Interacted compound 1 0.33 - 0.62 (yellow) Mixture 2 0.31 - o.64 (yellow) 0.94 - 1.00 (brown) Proparthrin 1 o.87 - 1.00 (brown) _ ~ _ ~... _.. -.. ,..... _ 5-Propargyl- ~-cyclodextrin 1 0.41 - o.64 (yellowi) furylmethyl- Interacted compound 1 0.37 - 0.59 (yellow) chrysanthe- Mi~ture 2 0.37 - 0.5~ (yellow) mate O.g3 - 1.00 (brown) ~pr~pàrgyl-~-ethy- 1 0.92 - 1.00 (brown) ~ ~ -nyl-2-furyl-methyl-chrysanthemate `
. _ ~ , - ., .~ , .
In the above table under the headline "Compounds tested", the term , :
"interacted compounds" denotes an interacted compound of a pyrethroid with ~- -cyclodextrin~ and the term "mixture", a mere mixture of a pyrethroid with ~- -cyclodextrin. The infrared spectra of the interacted compounds which occupy ~ J~

the spots on the thin-layer chromatogram are almost identical with those of the pyrethroid and ~-cyclodextrin superposed on each other, and also correspond with those of the mere m~xtures.
The following ~xamples illustrate the present invention in greater detail.
Formulation Example 1 96g of diatomaceous earth was added to 4g of an interacted compound of resmethrin and ~-cyclodextrin (25% by weight as resmethrin)~ and they were thoroughly stirred and mixed in a kneader to form dusts.
Formulation Example 2 30% by weight of an interacted compound of tetramethrin and ~- cyclo-dextrin (20% by weight ~S tetramethrin) was well mixed with 10 parts by weight of `.6~V ~mine salt of dodecylbenzene sulfonic acid and 60 parts by weight of 300-mesh talc was added. They were mixed well in a kneader with stirring to form a wettable powder.
Formulation ~xample 3 2g of an interacted compound of allethrin and F-cyclodextrin (25% by weight as aIlethrin), 1.5g of a synergist MGK-5026 (trademark for a mixture of N-octylbicycloheptenedicarboximide and an isopropylamine salt of dodecylbenzene-sulfonic acid)~ and 96.5g of a mosquito coil base consisting of pyrethrum ex-tracted dust, wood dust and starch were uniformly mixed and formed into a mos-quito coil by a con~entional method.
Formulation Example 4 2g of an interacted compound of furamethrin and ~-cyclodextrin (20%
by weight as furamethrin), 0.5g of 2,6-bis-t-butyl-4-methylphenol (anti-oxidant)~ `
and 97.5g of a mosquito coil base were uniforml~ mixed and formed into à mos-quito coil by a conventional method.

Formulation Example 5 :
70 parts bg weight of 300-mesh diatomaceous earth was added to 30 ~-parts by weight of an interacted compound of pyrethrin (pyrethrum extract powder) and B-cyclodextrin (1% by weight as pyrethrum extract powder), and they were thoroughly mixed and stirred in a kneader to form a dust.
Formulation ~xample 6 5g of an interacted compound of proparthrin and ~-cyclodextrin (20~
by wei~ht as proparthrin) was well mixed with 5g of white petrolactum. 30 ml.
of water was added to the mixture, and they were well kneaded to form a paste-like insecticide. ;~
About Sg of this insecticide was placed on a heater heated at 120-150 C. to volatil;ze the proparthrin~ and the resulting paste-like insecticide was used as an electric mosquito coil.
Formulation Example 7 4g of an interacted compound of f`uramethrin and ~-cyclodextrin (20% ~-by weight as furamethrin)~ 1.5g of piperonyl butoxide (synergist)~ 6g of stearic acid~ 4.5g of Span 60 (nonionic surfactant) and 2.5g of Tween 60 (non- `
ionic surfactant) were well mixed, and 31.5g of water was added to the mixture.
They were well kneaded to fonn a paste.
About 5g of this paste was placed on a heater held at 120 to 150 C. ~ -to volatilize the furamethrin~ and the resulting product was used as an elec- ~
1, .
trical mosquico coil.
Formulation Example 8

4~ of an interacted compound of proparthrin and ~-cyclodextrin (15%
by weight as proparthrin) and lg of a mixture of N-oct~lbicycloheptenedicar- ~
, boximide and an isopropyl amine salt of dodecylbenzenesulfonic acid (trade- - ~;
¦ mark~ MGK-5026) were uniformly mixed with 95 g of a mosquito coil base, and the mixture was made into a mosquito coil by a conventional method.
Formulation Example 9 98g of diatomaceous earth was added to 2g of an inter~cted compound `
of rethmethrin (15% by weight as proparthrin), and they were well stirred and ... -: . ~- ,.,. . . , , ~. .
. ,, . ~ ~ . - .
. ., . - . . .

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mixed in a kneader to form a dust.
Formulation Example 10 Seven interacted compounds were prepared from tetramethrin, dimethrin, phenothrin~ butethrin, 4-allylindane~l-yl-chrysanthemate, bena*hrin and ~-allyl-5-propargyl-3-furylmethyl-chrysanthemate using ~-cyclodextrin as a host crystal~ and a dust containing each of these compounds as an active ingredient was prepared.
Formulation ~xamPle 11 Three interacted compounds (25% by weight as pyrethroid) were pre-pared from allethrin, japothrin, and 5-propargyl~ ethynyl-2-furyl-methyl, chrysanthemate using~-cyclodextrin as a host crystal, and a mosquito coil was prepared from 2 g of each of these compounds and 98 g of a mosquito coil base.
Formulation Example 12 80g of an interacted compound of tetramethrin and r-cyclodextrin (15% by weight as tetramethrin), 5g of sodium ligninsulfonate, 5g of a butyl-amine salt of dodecylbenzenesulfonic acid, and lOg of clay were sufficiently stirred and mixed to form a wettable powder.
Formulation Example 13 90g of an interacted compound of phenothrin and~ -cyclodextrin and lOg of -isooctylphenoldecaethylene glycol ether were well stirred and mixed by a kneader to form a wettable powder.

~ .
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Using interacted compo~ds of various pyrethroids indicated in Table 3 below and cyclodextrin, mosquito coils containing 0.5~ by weight of pyre-throids were prepared in accordance with Formulation Examples 3, 4 and 8.
Using these mosquito coils, a test was conducted to knock down imargoes of house mosquitoes. The test procedure ~ras one disclosed at page 176 of Vol. 16 of the Japanese-language publication "Bochu-Kagaku~ (or Pest Control Science), 1951, page 176 and suggested by Nagasawa and Katsuda. The relative effective-.
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ness of the above mosquito coils were calculated. The results are shown in Table 3.
T_ble 3 ~ ~
. . - . ~ ~ . . .~ :
Pyrethroid compound 16% 50% 84%
knock down knock down knock down . _ , _ . .
` Allethrin 1.09 (1.00) 1.12 (1.00~ 1.13 (1.00) Pyrethrin 1.18 (1.09) 1.22 (1.14) 1.25 (1.18) Furamethrin 2.46 (2.^9) 2.51 (2.35) 2.58 (2.40) Proparthrin 2.23 (2.10) 2.27 (2.14~ 2.31 (2.20) The numbers in the table show the relative effectiveness of the interacted compounds, and those in the parentheses show the relative effective-ness of the pyrethroid alone. ~

. -:
Dusts containing 1% by weight of a p~rethroid as an effective in-gredi~ent were prepared in the same manner as in Formulation Examples 1 and 5 using various interacted compounds shown in Ta'ble 4. The resulting dusts were ~ ~
sprayed on a plywood at a rate of 8 g/m ~ and ~erman cockroaches were brou ht ~ -into contact with the dusts for 5iminutesO The time required for 50% knock~
down and the rate of dead cockroaches after a lapse of 24 hours were measured.
-~i The results are shown in Table 4.
Table 4 . . . . ~
Pyrethroid Time required Rate of dead for 50% cockroaches knockdown after 24 hours (%) _, _ .. - . .. :
Rethmethrin 4 minutes 80 20 seconds . , _ . . _ ~
Rethmethrin-cyclo-dextrin interacted 3 minutes 100 compound . _ . .
Pyrethrin 4 minutes 80 10 seconds '' : _ . _ __ ... .. . ~ :
.. . ., . . .. ~, ., :
... : .... : ... - .

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Table 4 Continued _ , ,. - = _ Pyrethroid Time required ~ate of dead for 50% cockroaches knockdown after 24 hours (%) _ _ , .

Pyrethrin-cyclodextrin 3 minutes 90 interacted compound 50 seconds _ _ _ ..
It is surprising to note from the above results of experiment that the insecticidal effect is superior when the interacted compound containing pyrethroid is used than when the pyrethroid is used alone.
Decomposition Test:-Interacted compounds of ~arious pyrethroids and cyclodextrin (molarratio of the cyclodextrin to the pyrethroid being 2 : 1) and pyrethroids alone were exposed to the irradiation of ultra~iolet rays for 60 hours, and respec-tively by gas-chromatographic analysis~ the amount of the pyrethroid decomposed was measured. The rate of decomposition was measured from the amount of de-composition determined. The results are shown in Table 5.
Table 5 . _ _ , , .
Rate of Decomposition (%) ., . . .
Pyrethroid Pyrethroid Interacted alone compound . . . . , _. . ., Allethrin 17.5 2.0 Te~tramethrin 8.8 0.9 Rethmethrin 14.7 1.8 Furamethrin 24.3 2.9 Proparthrin 30.5 3.4 It is seen from the results obtained that pyrethroids which are weak in resistance to ultraviolet rays have gained stability to ultraviolet rays by about tenfold.

Pest Control ~ ample 3 The same insecticidal test as in Pest Control Example 1 using the .

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seven mosquito coils prepared in Formulation Example 11 and in accordance with Formulation Example 11. The results are shown in Table 6.
Table 6 - . . . . ~ _. _ .
Pyrethroid compound 16% knockdown 50% knockdown 84% knockdown .. . . --- . .
Allethrin 1.06 (1 00) 1.10 (1.00) 1.14 (1.00) Japothrln 1.23 (1.15) 1.27 (1.19) 1.30 ~1.21) ~-

5-propargyl- ~-ethynyl-2-furylmethyl 1.89 (1.70) 1.95 (1.76) 2.03 (1.84) chrysanthemate 2-meth~lcy¢lopenta-2-ene-4-one-1-yl- 1.65 (1.54) 1.69 (1.573 1.72 (1.60)2,2~3,3-tetramethyl- -cyclopropane carboxylate ;

2~6-dimethyl-4-allyl-benz~l 2,2~3-trimethyl- 1.30 (1.21) 1.38 (1.25) 1.43 (1.27) ~ - ;
cyclopropane carboxylate 4_propargylbenzyl 2~2~3,3-tetramethyl- 1.41 (1.30) 1.47 (1~35) 1.52 (1.39) cyclopropane carboxylate ~-methyl-5-propargyl-2-furylmethyl~2,2~3-tri- 1.80 (1.68) 1.87 (1.71) 1.91 (1.75) ~;
mqthylcyclopropane carboxylate -. _ :
The figures ln the parentheses show the relative effectiveness of the .
pyrethroids used alone.
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Pest Control Example 4 The effects of the seven dusts prepared in Formulation Example 10 against houseflies and acaridia. lOOmg of each of the dusts was spread uni-forn~y on a filter paper placed in a Petri dish having an inside diameter of 9 cm and a height of 6 cm. Ten each of female and male house Mies and 10 acaridias w~re let free so as to be in contact with the dust spread for 60 minutes. The number of the dead after a lapse of 24 hours was observed. The test was conducted indoors~ and the temperature of the room at the time was 24 to 28 C. The results are shown in Table 7. -~ .
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3'' Table 7 _ . . _ . _ Pyrethroid compounds Rate of dead Rate of dead houseflies (%~ acaridias (%) _ . . .
Tetramethrin 100 ~85) 100 (90) Dimethrin 70 (50) 80 (60) Phenothrin 90 (80) 100 (90) 4-allylindane-1-yl- 7 (55) 60 (~5) chrysanthemate Butethrin 60 (50) 75 (60) Benathrin 85 (70) 95 (80) ~-allyl-5-propargyl-3~ 95 (85) 100 (80) furylmethyl chrysanthemate . . .:
The figures given in the parentheses show the rate of dead pests when the pyrethroid alone was applied.
Pest Control Example 5 Each of the wettable powder of Formulation Example 2 and that of Formulation Example 13 were applied to Ch~nese cabbages grown in pots on which 4th-instar larvae of white butterflies lived. The res~lts are shown in Table ': , .
8.
Table 8 _ _ _ _ . , . _ ~ .
Test chemicals Diluted Amount of Rate of dead to the effecti~e larvae after ingredient 2~ hours (%~
. _. . .. ,~ . . . _, _ . __ Tetramethrin wet-table powder (Form- 200 times 0.03 go (78) ulation Example 2) ~, Phenothrin wettable powder (Formulation 600 times 0.03 95 (85) Example 13) _ _ _ _ The figures in the parentheses show the rate of dead lar~ae when the pyrethroid alone was applied.

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Pest Control Example 6 A stomach poison test on houseflies was perfo~med using an inter-acted compound of bio-allethrin and ~-cyclodextrin (the molar ratio of the bio-allethrin to the ~-cyclodextrin being 1 : 2).
Twenty houseflies (male and female) of the Takatsuki strain after four days from emergence were used in each of the following four kinds of test.
(a~ 90 mg of sugar powder and absorbent cotton impregnated with about 2 ml. of water were used.
(b) 90 mg of a mixture of sugar powder and ~-cyclodextrin in a weight ratio of about 1:1, and about 2 ml. of water impregnated with water were used. ~-~
(c) 90 mg of an interacted compound and bio-allethrin and ~-cyclo-dextrin were used.
(d) 90 mg of a mixture of the above interacted compound and sugar in a weight ratio of about 1:1, and absorbent cotton impregnated with about 2 ml. of water were used.
In each oase, obserration was made after 40 minutes, 80 minutes, 210 minutes~ and 12gO minutes~ The results (the nttmber of dead houseflies) are shown in Table 9.

_ - . , _ _ _ _ . .
Time that \ èlapsed 40 80 210 1280 Case \ minutesminutes minutes minutes (a) 1 1 1 1 (b) 1 1 1 1 (c) 15 20 19 20 (d3 12 16 19 20 _ ,, I . - r , _ _ .. . .
It is seen from the results obtained that cyclodextrin does not show : ,, . - , ~ , . . .

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>7'~3 stomach poison~ and bio-allethrin exhibits good stomach poison even when used as an interacted compound wi-th cyclodextrin. ~-The fact that the number of dead houseflies in case ~d) is smaller than in case (d) at the initial stage is considered due to the fact that the concentration of the interacted compound was diluted as a result of dilution with sugar. Similar results were observed when an interacted compo~d of ~-cyclodaxtrin with bio-resmethrin~ biotetramethrin~ or furamethrin was used.
Pest Control E_ample 7 A stomach poison test was conducted on pine caterpillars using an interacted compound of bio-allethrin and ~-cyclodextrin, and an mteracted com-pound of bioresmethrin and ~-cyclodextrin (in each case, the molar ratio of pyrethroid to ~-cyclodextrin was 1:2).
In each test, eight 4th-instar larvae of pine caterpillars (body ;
length 2 to 2.5 cm)were used. Six kinds of test were conducted. In each test, 40 pine leaves (8 ~ 10 cm long, about 2 g? were used either in the non-treated state or as treated with ~-cyclodextrin, pyrethroid and the a~ove interacted compounds respectively. The results ~the number of dead pests) are shown in Table 10. In the Table~ the figures in the parentheses show the percentage of ~h~ re:aining pine leaves.

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It is seen from the results obtained that both of bio-allethrin and bio-resmethrin have much the same stomach poison effect even when used as an interacted compound with ~~cyclodextrin.
In all cases, the rate of dead insects is low at the initial stage when the interacted compounds of pyrethroids are used. But after a lapse of as long as 76 hours, there is hardly any difference in the rate of dead insects.
When using pine leaves to which a pyrethroid as an interacted com-pound of pyrethroid with ~-cyclodextrin had been adhered, the pine cater-pillars fell off from the pine leaves and were observed to be in agony on the ~
floor, all~haug~ not to death. Accordingly, the pine caterpillars which are I ;
the pyrethroid first fell from the pine leaves, and gradually die, and in view of this, the amount of the pine leaves eaten is very small irrespective of the time duration required before death, and the damage can be minimized.
Since pyrethroids have poor stability to ultraviolet rays~ even if ~-they are used as a mixture with starch~ etc. as shown in Table 1~ they lose their effect. But when used as interacted compounds with cyclodextrins, the pyrethroids become very stable to ultraviolet rays~ and are scarcely decomposed for a prolonged period of time. This is especially advantageous for outdoor application of the pesticidal composition of this in~ention~ as in the case of ~0 controlling the pine caterpillars. Furthermore, this demonstrates that pyre-throids can be very effecti~ely utilized by using them as interacted compounds with cyclodextrins.

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Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. The molecular compound of a pyrethroid with a cyclodextrin,

2. A compound according to claim 1 wherein the pyrethroid is a compound of the formula (I) wherein R1 is methyl or methoxycarbonyl, and R2 is pent-2,4-dienyl,2-butenyl or 2-pentenyl.

3. A compound according to claim 1 wherein the pyrethroid is a com-pound of the formula (II) wherein R3 is methyl or isobutenyl, R4 is hydrogen or methyl, and R5 is allyl or propargyl.

4. A compound according to claim 1 wherein the pyrethroid is a com-pound of the formula (III) wherein R3 is methyl or isobutenyl, and R4 is hydrogen or methyl.

5. A compound according to claim 1 wherein the pyrethroid is a compound of the formula (IV) wherein R3 is methyl or isobutenyl, R4 is hydrogen or methyl, X is methyl, allyl, propargyl, benzyl or phenoxy, and n is 1, 2 or 3 with the proviso that when n is 2, at least one X is methyl, and when n is 3, at least two X's are methyl.

6. A compound according to claim 1 wherein the pyrethroid is a compound of the formula (V) wherein R3 is methyl or isobutenyl, R4 is hydrogen or methyl, R6 is hydrogen, methyl or C2 to C3 alkyl, alkenyl or alkynyl, Y is methyl, allyl, propargyl or benzyl, Z is -S- or -O-, and m is 1 or 2, with the proviso that when m is 2, at least one Y is methyl.

7. A compound according to claim 1 wherein the pyrethroid is a compound of the formula (VI) wherein R3 is methyl or isobutenyl, R4 is hydrogen or methyl, R6 is hydrogen, methyl or C2 to C3 alkyl, alkenyl or alkynyl, Y is methyl, allyl, propargyl or benzyl, Z is -S- or -O-, and m is 1 or 2, with the proviso that when m is 2, at least one Y is methyl.

8. A compound according to claim 1 wherein the pyrethroid is barthrin, butethrin or 4-allylindan-1-yl chrysanthemate.

9. A compound according to claim 1 or 2 wherein the cyclodextrin con-sists of 6 to 8 glucose units cyclically bonded.

10. A compound according to claim 3, 4 or 5 wherein the cyclodextrin consists of 6 to 8 glucose units clycically bonded.

11. A compound according to claim 6, 7 or 8 wherein the cyclodextrin consists of 6 to 8 glucose units cyclically bonded.

12. A compound according to claim 1 or 2 wherein the molar ratio of the pyrethroid to the cyclodextrin is from 0.5:1 to 1.5:1.

13. A compound according to claim 3, 4 or 5 wherein the molar ratio of the pyrethroid to the cyclodextrin is from 0.5:1 to 1.5:1.

14. A compound according to claim 6, 7 or 8 wherein the molar ratio of the pyrethroid to the cyclodextrin is from 0.5:1 to 1.5:1.

15. A method for controlling insect or acarid pests which comprises applying to the pests or to a habitat thereof a pesticidal amount of a com-pound according to claim 1 or 2.

16. A method for controlling insect or acarid pests which comprises applying to the pests or to a habitat thereof a pesticidal amount of a com-pound according to claim 3, 4 or 5.

17. A method for controlling insect or acarid pests which comprises applying to the pests or to a habitat thereof a pesticidal amount of a com-pound according to claim 6, 7 or 8.