Note: Descriptions are shown in the official language in which they were submitted.
11311Z'~
PESTICIDA~ COMPOSITION AND ~ETHOD OF COMBATING PESTS
This invention relates to a pesticidal composition and to
a method of combating pests.
The Applicant has found that a composition including the
known acaricide, N,N-di-(2,4-xylyliminomethyl)-methylamine
and certain pyrethroid insecticides possess synergistic activity
with respect to acarid pests; that is to say, the activity of
the combination of the two pesticides produces a more-than-
additive pesticidal ef~ect.
Accordingly, the present invention provides a pesticidal
composition which comprises N,N-di-(2,4-xylyliminomethyl)-
methylamine (hereinafter referred to as "amitraz") charac-
terized in that the composition includes a pyrethroid insect-
icide having the general formula:
O R ~ ~ (X)n
A - C - O - CH ~ (I)
wherein A is an optionally-subs'ituted aralkyl, alkyl or
eycloalkyl group, R is hydrogen, eyano or ethynyl, X is alkyl,
alkenyl, aralkyl or aryloxy, and n is 1 to 5.
Generally speaking, an alkyl, cycloalkyl or alkenyl group
represented by A or X preferably contains up to 6 carbon
Y . , .
~;
.... . ..
: . :
~13~29
atoms and an aralkyl or aryloxy group represented by A or X
preferably contains up to 10 car~on atoms.
It should be noted that the pyrethroid insecticide I can
exist in the form of optical isomers or cis-trans-isomers and
in the composition according to the invention an individual
isomer or mixture of isomers including racemates may be employed.
Preferably, A represents an optionally-substituted aralkyl
group in general formula I. Especially preferred compounds of
the general formula I are those in which A represents a sub-
stituted benzyl group of the general formula:
~ / ~ Q
z
wherein Z represents a halogen, preferably a chlorine, atom, or
an alkoxy group having 1 to 4 carbon atoms, for example a methoxy
group, and Q represents an alkyl group having from 1 to 6 carbon
atoms, especially a branched-chain group, for example an iso-
propyl group. The most preferred compounds of the generalformula I are those wherein A represents an alpha-isopropyl-4-
chlorobenzyl group, R represents a hydrogen atom or a cyano
group, n is 1, and X represents a 3-phenoxy group, for example
alpha-cyano-3-phenoxybenzyl alpha-isopropyl-4-chlorophenyl
acetate.
If, however, A represents an optionally-substituted cyclo-
alkyl group in general formula I, the preferred compounds of
this type are those wherein A represents a cyclopropyl group
of formula:
a ~ b
Rc / ~ H
Rd
li31~Z'~
wherein Ra and Rb each individually represent an alkyl group
having from 1 to 6 carbon atoms, especially methyl or a
halogen, especially chlorine, bromine or fluorine atom; or
Ra and Rb together represent an alkylene group having from
2 to 6, especially 3, carbon atoms; or Ra represents a hydrogen
atom and Rb represents an alkenyl group having from 2 to 6
carbon atoms, especially an isobutenyl group, or a halo-
alkenyl group having from 2 to 6 carbon atoms and from 1 to
3 chlorine or bromine atoms, especially a mono- or dichloro-
vinyl group; Rc and Rd both represent an alkyl group having
1 to 6 carbon atoms, especially a methyl group, or Rc and Rd
together represent an alkylene group having from 2 to 6,
especially 3, carbon atoms. Thus, for~xample, A may represent
a 2,2,3,3-tetramethylcyclopropyl group while R represents a
hydrogen atom or a cyano group, n is 1 and X is 3-phenoxy.
The mixture of amitraz and the pyrethroid insecticide not
only produces a pesticide having a markedly wider spectrum of
activity than the pyrethroid or the amitraz alone, but also
produces a surprising synergistic effect with respect to acarids,
e.g., glasshouse red spider mite, Tetranychus urticae. The
mixture also possesses useful properties with respect to the
eggs of lepidopterous and acharine pests; it has uses in
the agrochemical and animal health fields.
The weight ratio of the pyrethroid insecticide to amitraz
may be in the range 5:1 to 1:50.
The pesticidal composition according to the invention
preferably also comprises a carrier, especially at least two
carriers, at least one of which is a surface-active agent.
A carrier may be a solid or liquid material, which may be
inorganic or organic and of synthetic or natural origin.
~ypical solid carriers include natural and synthetic clays
and silicates, for example, natural silicas, for example
diatomaceous earths, and aluminium silicates, for example
kaolinites, montmorillonites and micas. Typical liquid
~31129
carriers are ketones, for example methylcyclohexanone, aromatic
hydrocarbons, for example methylnaphthalenes, petroleum fract-
ions, for example petroleum xylenes and light mineral oils, and
chlorinated hydrocarbons, for example carbon tetrachloride.
Mixtures of liquids are often suitable.
One or more surface-active agents and/or stickers can be
included in the composition. A surface-active agent may be an
emulsifying agent or a dispersing agent or a wetting agent; it
may be non-ionic or ionic. Any of the surface-active agents
usually applied in formulating insecticides may be used.
Examples of suitable surface-active agents are the sodium and
calcium salts of polyacrylic acids and lignin sulphonic acids;
the condensation products of fatty acids of aliphatic amines or
amides containing at least 12 carbon atoms in the molecule with
ethylene oxide and/or propylene oxide; fatty acid esters of
glycerol, sorbitan, sucrose or pentaerythritol~ condensates of
these with ethylene oxide and/or propylene oxide; c~ndensation
products of fatty alcohols or alkyl phenols, for example p-
octylphenol or p-octylcresol, with ethylene oxide and/or
propylene oxide; sulphates or sulphonates of these condensation
products; alkali or alkaline earth metal salts, preferably
sodium salts, of sulphuric or sulphonic acid esters containing
at least 10 carbon atoms in the molecule, for example sodium
lauryl sulphate, sodium secondary alkyl sulphates, sodium salts
of sulphonated castor oil, and sodium alkylaryl sulphonates,
such as sodium dodecylbenzene sulphonate; and polymers of
ethylene oxide and copolymers of ethylene oxide and propylene
oxide.
The composition of the invention may for example be
formulated as a wettable powder, microcapsules, a dust, granules,
a solution, an emulsifiable concentrate, an emulsion, a sus-
pension concentrate or an aerosol. ~he composition may have
controlled release properties, or may be suitable for use as
a bait.
_ . . ~
~llZ9
Wettable powders usually contain 25, 50 or 75%w of active
ingredient and may contain, in addition to inert solid material,
3-10%w of a dispersing agent and, where necessary, 0-10%w of a
stabilizer, a penetrant and/or a sticker. A dust is usually
formulated as a dust concentrate having a composition similar
to that of a wettable powder but without a dispersant, and is
diluted in the field with further solid carrier to give a
composition usually containing 2-10%w of active ingredient.
Granules usually have a size in the range of from 10 to
100 BS mesh (1.676-0.152 mm) and may be manufactured by
agglomeration or impregnation techniques. Generally, granules
will contain ~-25%w active ingredient and 0-10%w of additives,
for example a stabilizer, slow-release modifier and/or a binding
agent.
Emulsifiable concentrates usually contain, in addition to
a solvent, and, when necessary, co-solvent, 10-50%w/v active
ingredient, 2-20%w/v emulsifier and 0-20~ow/v of other additives,
for example a stabilizer, a penetrant and/or a corrosion in-
hibitor. A suspension concentrate is a stable, non-sedimenting,
flowable prcduct and usually contains 10-751ow active ingredient,
0.5-151ow of dispersing agent, 0.1-10%w of suspending agent, for
example protective colloid and for a thixotropic agent, and
0-101ow of other additives including, for example, a defoamer,
a corrosion inhibitor, a stabilizer, a penetrant and/or a
sticker, and as dispersant, water or an organic liquid in
which the active ingredient is substantially insoluble;
certain organic additives and/or inorganic salts may be
dissolved in the dispersant to assist in preventing sediment-
ation or as anti-freeze for water.
The aqueous dispersions and emulsions formed by diluting
a wettable powder or an emulsifiable concentrate of the in-
vention with water, also lie within the scope of the present
invention. Such dispersions and emulsions may be of the
water-in-oil or of the oil-in-water type, and may have a
thick "mayonaise"-like consistency.
113~ 9
A composition of the invention may also contain other
ingredients, for example, one or more other compounds possessing
pesticidal, herbicidal or fungicidal properties, or attractants,
for example pheromones or food ingredients, for use in baits
and trap formulations.
The invention also includes a method of combating pests at
a locus characterized in that a pesticidal composition according
to the invention is applied to the locus.
The invention is further illustrated by the following
Example, in which the joint action of two pesticides was
analyzed according to the method of Yun-Pei Sun and E.R.Johnson,
Journal of ~conomic Entomology, 1960, Volume 53, No. 5, pp. 887-892.
Thus, the joint action of two pesticides was analyzed by
determining the actual toxicity indices of the components and
f mixtures of the compounds by reference to dosage-mortality
curves. The theoretical toxicity of the mixture is equal to
the sum over both components of the percentage of each
individual compound multiplied by its respective toxicity
index. Therefore, the joint toxicity or co-toxicity coefficient
of a mixture
Actual toxicity index of a mixture
Theoretical toxicity index of a mixture x 00
A eoeffieient of a mixture near 100 indieates probability of
similar action by the two pesticidesiindependent action usually
should give a coefficient less than 100, while a eoefficient
significantly above 100 strongly indieates synergism.
The compounds tested in the Example are shown below.
Amitraz CH3
N = CH - N - CX = N
C~\/C~3 /~
1131~Z~
Compound Y
C ~ C~
Cl 4 ~ H - C0.0 - C
\=~' \C/
EXAMPLE
Activity of Pyrethroid/Amitraz mixture a~ainst Tetranychus
urticae (glasshouse red spider mite)
The acaricidal activity of amitraz, compound Y and their
mixtures was assessed by the following method.
The compounds and mixtures were formulated as solutions or
suspensions in water containing 20% by weight of acetone and
0.05% by weight of Triton X-100 (Trade Mark) as wetting agent.
The formulations contained 0.4% by weight of the compound or
mixture to be tested and were diluted to produce formulations
containing various c~entrations. Leaf discs cut from French bean
plants were sprayed with the formulations and left for 2 to 1
hour drying period. Each leaf disc was then inoculated with 10
red spider mites and mortality counts made 2~ hours after
inoculation. From these results the LC50's (the concentration
by weight of active material in the spray required to kill 50%
of the mite population) could be calculated.
The toxicity indices of the compounds and the mixtures
were calculated using the following formula:
LC50 of amitraz
Toxicity IndeX = LC f compound or mixture
The coefficient of cotoxicities were then calculated ac-
cording to the method described above. The results are shown
in the following Table.
il311Z9
TABLE
ACTIVITY OF PYRETHROID ~XTURES AGAINST THE
GLASSHOUSE RED SPIDER MITE (TETRANYCHUS URTICAE)
Replicates Coefficient of co-
Treatment Replicates
¦ 1 2 1 2
Amitraz 0.12 0.14 _ _
..
Compound Y ¦ 0.40 0.36 _ _
... .
Compound Y +
Amitraz0.17 0.17 133 141
(2:1 ratio) .
It will be seen that the coefficients of cotoxicity are both
in excess of 100 and clearly demonstrate the synergistic effect
of the amitraz/pyrethroid mixture.
