This invention relates to stabilized active materials. Particularly,
the invention relates to the stabilization of insect pheromones.
Methods of eliminating unwanted pests from orchards, crops and forests
frequently entail the use of organophosphate insecticides. Alternative methods involve
insect mating disruption, where insect pheromones are used to control pests in any
desired location, including protecting agricultural crops and forestry. In insect
mating disruption methods, the mating pheromone plume of a female insect is typically
masked with other pheromone point sources. This reduces the likelihood of a male
insect finding a female, and subsequently disrupts and reduces larvae production.
The insect population of the next generation is thus decreased, as well as potential
Stabilization methods for insect pest pheromones are known, such as
described in U.S. Patent No. 5,364,969 (Sakurada et al). Sakurada
et al describe admixing the sex pheromone compound with a specified amount
of (a) a specific phenolic compound, e.g. tert-butyl hydroquinone, di-tert-butyl
hydroquinone, di-tert-amyl hydroquinone, di-tert-buytl p-cresol, methyl hydroquinone
and p-methoxy phenol, as an antioxidant and (b) 2-(2'-hydroxy-3'-tert-butyl-5'-methyl
phenyl)-5-chlorobenzotriazole in combination.
JP-A-10/279402 describes a liquid chemical heat evaporation method
which can be used for certain liquid chemical compositions. DE-A-41 36 832 discloses
a method for stabilizing a long-chain, aliphatic compound having at least ten carbon
atoms and at least one double bond, characterized in that 2-(2'-hydroxy-5-methylphenyl)benzotriazol
and a phenolic compound as an antioxidant are each added to the compound in an amount
of 0.1 to 10 wt.-% based on the long-chain, aliphatic compound. J. Econ. Entomol.
(1995), 88(5), 1426-1432 relates to the degradation of E8,E10-dodecadienol and its
stabilization by carbon black and 2-phenylenediamine antioxidants. JP-A-08/034705
describes certain insect-proofing or insecticide agents which optionally contain
certain phenol, hydroquinone or hydroquinone monomethyl ether type stabilizer agents.
The need still exists to stabilize an insect pheromone to ensure efficacy
over the typical mating season of the insect pests.
This invention relates to a method of stabilizing an insect pheromone
composition using 2,2'-methylenebis(6-t-butyl-p-cresol), CAS No. 119-47-1. The present
invention also relates to an insect pheromone composition comprising a pheromone
Another aspect of the present invention relates to a composition further
comprising a benzotriazole, and in preferred cases, 2-(2'-hydroxy-3',5'-di-tert-amyl-phenyl)
Yet, another aspect of the present invention relates to a method of
protecting a crop against insect pests by applying a microcapsule comprising an
insect pheromone, and 2,2'-methylenebis(6-t-butyl-p-cresol).
The present invention provides a composition that is stabilized to
provide extended release of the insect pheromone over a typical flight season for
insect pests. Typically, a generation of Lepidopteran insects averages approximately
6 weeks. Thus, a sustained release period of at least 6 weeks for the particular
insect pheromone would provide for effective disruption of the insect pest mating
during its flight period when the pheromone is introduced into the intended environment.
A stable insect pheromone composition allows for a reduced frequency
of application. A pheromone that is effective throughout an entire generation of
an insect pest eliminates the need for subsequent applications to ensure mating
disruption of the insect pests.
Because the insect pheromone can be provided in a stabilized format,
a long lasting delivery system may be engineered to provide slow release over a
long duration of time. The stabilized format allows for a slow release from a single
application without spiking as may be obtainable from multiple applications. "Spiking"
as used herein may be triggered by instantaneous or short-term release of the active
agents from the shell. Since a mating cycle of a given insect pest may last up to
4-6 weeks in length, the slow release of an insect pheromone may be desirable to
provide effective control of insect mating over the duration. Thus, the present
invention may be used to control the release rate of insect pheromones thereby effectively
controlling and disrupting the mating behavior of the species in a particular intended
environment. For example, an insect pheromone for codling moth can be made to steadily
dissipate into the intended environment over the duration of a mating cycle for
codling moth. A typical duration for a nonstabilized codlemone, the insect pheromone
for the codling moth is less than 1 week, as against about 6 weeks for codlemone
stabilized according to the present invention.
A stabilized composition of insect pheromone according to the present
invention comprises 2,2'-methylenebis(6-t-butyl-p-cresol). Insect pheromones stabilized
using 2,2'-methylenebis(6-t-butyl-p-cresol) alone, or in combination with additional
stabilization agents, show remarkable efficacy over an extended period of time.
The term "efficacy" as used in the present invention relates to the stability of
the insect pheromone in showing mating inhibiting effect over a period of time.
A preferable duration of mating inhibiting may be greater than 4 weeks, more preferably
greater than 6 weeks, and most preferably greater than 8 weeks.
The stabilizer of the present invention may preferably be combined
with UV absorbers including, but not limited to benzotriazoles, hindered amine light
stabilizers (HALS), cinnamate esters, hydroxybenzophenones, and oxanilides. Typical
benzotriazoles usable in the present invention include 2-(2'hydroxy-3',5'-tert-amylphenyl)benzotriazole;
2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chloro-benzotriazole; and the like.
Additional stabilizers may also be incorporated, such as nickel and sulfur containing
quenchers and hydroperoxide/peroxide scavengers. UV absorbers as used in the present
invention relate to chemical additives used to improve the stability of the insect
pheromone against ultraviolet degradation.
UV blockers may also be combined with the stabilizer of the present
invention. Typical UV blockers such as carbon black and titanium dioxide are usable.
Other antioxidants are also usable to provide a stabilized insect
pheromone of the present invention such as those in the family of sterically hindered
phenols, bisphenols, aminophenols, secondary aromatic amines, hydroxybenzyl compounds,
alkyl and arylthioethers, thiobisphenols, phosphites and phosphonites, and zinc-thiocarbamates,
and the like.
Preferred ratios of insect pheromone to 2,2'-methylenebis(6-t-butyl-p-cresol)
may be in the range between 200:1 and 0.5:1; more preferably between 50:1 and 0.5:1;
and most preferably in the range between 20:1 and 1:1. Preferred ratios of insect
pheromone to UV absorber in the composition may be in the range between 200:1 and
0.5:1; more preferably between 50:1 and 0.5:1; and most preferably in the range
between 20:1 and 1:1.
Pheromones may be defined as compounds which, when naturally produced,
are secreted by one member of an animal species which can influence the behavior
or development of another member of the same animal species. Pheromones are species-specific
and therefore the application of pheromones for insect behaviour modification has
minimal effect on non-target pests. Pheromones supplied for modification of insect
behavior interfere with the "mate finding process" by releasing point sources of
pheromone, which may compete with or camouflage the pheromone plume of a female
of the same species. This latter type of action differs from chemical insecticides
or insect growth regulators or hormones, in that pheromones target future generations
of insects, not present ones. As pheromones are very species-specific and are used
only in small quantities, their use is more environmentally acceptable than broadcasting
Pheromones useful in the invention are preferably insect pheromones.
In describing the structure of the pheromone, the following notation is used: the
type (E (trans) or Z(cis)) and position of the double bond or bonds are given first,
the number of carbon atoms in the chain is given next and the nature of the end
group is given last. To illustrate, the pheromone Z-10 C 19 aldehyde has the structure;
Pheromones can be mixtures of compounds with one component of the
mixture predominating, or at least being a significant component. Predominant components
of insect pheromones, with the target species in brackets, include, for example:
E/Z-11 C14 aldehyde (Eastern Spruce Budworm), Z-10 C19 aldehyde (Yellow Headed Spruce
Sawfly), E,E-8,10 C12 alcohol (Codling moth), E-11 C14 alcohol/acetate (Tufted Apple
Budmoth), E-11 C14 acetate (Sparganothis Fruitworm), Z-11 C14 acetate (Blackheaded
Fireworm), Z-9 C12 acetate (Grape Berry Moth), Z-11 C14 acetate (Leafroller), E/Z-4
C13 acetate (Tomato Pinworm), Z,Z/Z,E-7,11-C16 acetate (Pink Cotton Bullworm), Z-8-C12
acetate (Oriental Fruit Moth), Z/Z-3,13 C18 acetate (Peach Tree Borer), E,Z/Z,Z-3,13-C18
acetate (Lesser Peach Tree Borer), and 7,8-epoxy-2-methyl-C18 (Gypsy Moth), among
An example of a ketone that is a pheromone is E or Z 7-tetradecen-2-one,
which is effective with the oriental beetle. An ether that is not a pheromone but
is of value is 4-allylanisole, which can be used to render pine trees unattractive
to the Southern pine beetle.
Stabilized insect pheromones according to the present invention may
be provided in any delivery vehicle appropriate for the intended environment. Examples
of such delivery vehicles include microcapsules, microbeads, plastic laminate flakes
and larger mechanical devices such as hollow fibres and twist ties.
Microcapsules may be formed for example using conventional polyurea
and/or polymethyleneurea encapsulation techniques such as what is taught in U.S.
Patent Nos. 3,516,941 (Matson), 3,577,515 (Vandegaer), and 4,487,759 (Nesbitt
et al). Alternatively, microcapsules having gelatin shells may be used in
the microbeads of the invention and prepared by the methods provided in U.S. Patent
No. 4,402,856. In another embodiment, microcapsules may alternatively be provided
in the form of a liposome, and prepared by the processes taught in U.S. Patent No.
4,911,928. Other examples of microcapsules are disclosed in U.S. Patent Nos. 3,691,140;
5,045,569; and 5,508313 as well as European Patent Application 371,635.
United Kingdom Patent No. 1,371,179 also discloses the preparation
of polyurea capsules for containing dyes, inks, chemical reagents, pharmaceuticals,
flavoring materials, fungicides, bactericides and pesticides such as herbicides
and insecticides. Particle sizes as low as one (1) micron are exemplified. Encapsulation
of insect hormones and mimics are among the systems mentioned.
Canadian Patent No. 1,179,682 discusses encapsulation of pheromones.
Microcapsules containing pheromones are produced from toluene diisocyanate and ethylene
diamine and/or diethylene triamine.
The microcapsules of the present invention may optionally also have
adherent coatings to aid the microcapsule to adhere to the intended environment,
especially when the microcapsules are used for agricultural purposes. Examples of
adherent coatings include tacky microspheres of adhesives. The tacky microspheres
have sufficient adhesive properties to provide the desired adhesive function, and
do not present a danger of completely coating the microcapsule and possibly inhibiting
the release characteristics of the particle. Preferably, the adhesive material is
an acrylate or methacrylate-based adhesive system comprising infusible, solvent
dispersible, solvent insoluble, inherently tacky elastomeric copolymer microspheres
as disclosed in U.S. Patent 3,691,140 to Silver, as well as those disclosed in U.S.
Patent No. 5,045,569 to Delgado, and U.S. Patent No. 5,508,313 to Delgado et al.
Other types of adhesive usable in the present invention include adhesive latex such
as Companion™ and Rhoplex™, available from Rohm & Haas Company,
Philadelphia, Pennsylvania; DPI S-100™, available from Deerpoint Industries
of Hawthorn Woods, Illinois.
Microbeads comprise a matrix forming material, and are preferably
substantially spherical. The matrix forming materials of the microbead core are
hydrophilic and water soluble. Entrained or finely dispersed within the matrix are
micro-sized droplets of active material such as insect pheromone. Insect pheromones
that can be immobilized within the hydrogel microbeads include acetates, aldehydes,
alcohols, esters, epoxy compounds, ethers, and ketones, especially reactive ketones
in which the double bond of the carbonyl group is conjugated with one or more double
bonds, for example acetophenone where the carbonyl group is conjugated with double
bonds of the aromatic ring. Examples of microbeads are disclosed in U.S. Patent
Nos. 4,689,293; 4,755,377; and 5,645,844.
In view of the increasing awareness of insecticide toxicity to humans
and other environmental concerns, it would be advantageous to provide an insect
pheromone delivery system having an extended release life and having a hydrogel
material in order that it be non-toxic and bio-degradable. It would also be advantageous
to provide a system for sprayable long lasting insect pheromone delivery that would
be applicable to a broad spectrum of insect pheromones thereby eliminating the issue
of reactivity of the insect pheromone with one of the membrane components.
Advantageously, the hydrogel matrix core is preferably made from environmentally
or biologically friendly materials to provide sufficient immobilization of oil soluble
insect pheromones such that the insect pheromone can be delivered and sprayed by
conventional techniques. By utilizing a hydrophilic matrix core, the hydrogel microbeads
entrap micro-sized droplets of insect pheromone within the matrix. This is in contrast
to delivery systems that solely utilize microencapsulation of insect pheromones,
achieved by interfacial polymerization. Immobilizing insect pheromone in a hydrophilic
matrix core advantageously imparts the capability of the hydrogel microbeads to
immobilize oil-soluble insect pheromones and minimizes the risk of undesired reactivity
between the insect pheromone and its immobilizer. Thus, immobilization of insect
pheromones by use of the microbeads of the invention does not render the immobilized
material inert or ineffective.
In the presence of humidity, the hydrogel microbeads are surprisingly
found to be capable of absorbing moisture, rehydrating, and consequently releasing
insect pheromone contained within the microbead. This behavior can be cyclical.
Thus, by controlling the humidity (or dryness) of the ambient air, the release rate
of insect pheromone from the microbeads can be controlled such that specific periods
of release can be generally predicted. It is therefore possible to release the insect
pheromone on demand from the microbead. Release on demand, or "smart release," can
be advantageous in those instances where release is preferred at certain times.
The microbeads' ability to release more insect pheromone out from the matrix may
increase the longeveity of the release period. Preferably, the microbeads are delivered
to an intended environment in effective amounts to obtain the desired effect. For
example, microbeads having pheromones entrained therein, are preferably delivered
to a desired area in amounts such that mating disruption is effected and release
is accomplished for more than 4 weeks, more preferably, the microbead can release
for more than about 6 weeks; and most preferably more than about 8 weeks.
Typically, each microcapsule of the present invention has an insect
pheromone or pheromones encapsulated or retained in it. The pheromones may be employed
in combination with other chemicals and/or materials used to facilitate the effectiveness
of the microcapsules in their intended environment. In an embodiment to protect
against the Leafroller species of pests, and in particular the Redbanded Leafroller
(Argyrotaeniavelutinana), the insect pheromone effective for their
control consists of 88:12 ratio of Z-11-Tetradecenyl Acetate to E-11-Tetradecenyl
The insect pheromone of the present invention may be delivered in
any manner appropriate for use in the intended environment. Most preferably, the
insect pheromone of the present invention may be provided in microencapsulation
Conventional sprayable pheromone formulations are generally provided
in liquid filled microcapsules containing an insect pheromone. Typically, the microcapsules
have a polyurea membrane that can be formed using an interfacial process involving
an isocyanate and an amine. Microencapsulation by this method has been described
for example in U.S. Patent 4,487,759 (Nesbitt et al). These polyurea membranes
allow insect pheromones to be released into the atmosphere for up to a total of
2-3 weeks for most insect pheromones.
For spraying applications, particularly aerial spraying, it is desirable
that the microbeads be capable of remaining suspended in solution (e.g., water)
to ensure that the microbeads do not sink, settle, or coagulate in the suspension.
A uniform suspension ensures an even spray coverage. Preferably, the microbeads
are able to remain in suspension, thus minimizing if not eliminating the need to
agitate during application (and storage). Various suspension aids can also be included
in the suspension containing the microbeads.. Examples of suitable suspension aids
include rhamsam gum, xanthum gum, gellan gum, pectin, and gum arabic.
Owing to the handling to which the microbeads are subjected, it is
desirable that the microbeads should be somewhat elastic, and not frangible. For
example, typical atomization of a suspension during a spray application will force
the suspension through two rotating perforated discs that are immediately upstream
of the discharge nozzle. Sufficient elasticity of the microbeads minimizes physical
damage to the microbeads as they pass through the discs.
The microcapsules may be delivered to the intended environment by
methods as are known in the art, such as spraying. Preferably, the microcapsules
of the present invention should remain in suspension in water or any suitable solution.
A suspension aids the delivery by preventing the microcapsules from sinking and
coagulating before spraying. It is preferable to reduce this settling process, although
it can be restored to some extent by agitation, the necessity of which is one disadvantage.
Use of interfacial polymerization to encapsulate substances such as
pharmaceuticals, pesticides and herbicides is taught in U. S. Patent No. 3,577,515.
The encapsulation process involves two immiscible liquid phases (typically water
and an organic solvent), one being dispersed in the other by agitation, and the
subsequent polymerization of monomers from each phase at the interface between the
bulk (continuous) phase, and the dispersed droplets. Polyurethanes and polyureas
are materials suitable for producing the microcapsules. The microcapsules comprise
a polymeric sphere and a liquid center, ranging from 30 micron to 2 mm in diameter,
depending on monomers and solvents used.
Highly viscous and thickened hydrogels have been used to deliver pheromones,
fragrances and other water-insoluble insect pheromones. U.S. Patent No. 4,755,377,
for example, describes a process of encapsulating perfume or fragrant material within
an aqueous-based gel composition. The resulting material is in the form of a highly
viscous semi-solid. U.S. Patent No. 5,645,844 describes the use of chitosan paste
for delivery of pheromones to disrupt insect mating, where the material can be dispensed
by an apparatus such as a caulking gun.
Most hydrogels are safe and non-toxic to humans. Hydrogels have been
used for the encapsulation of biological materials whereby the formulation is non-lethal
to the viability of the cells, proteins, and related materials. U.S. Patent No.
4,689,293 describes the process of encapsulating living tissue or cells in alginate
beads. The encapsulation shell permits the passage of materials and oxygen to the
cells and permits the diffusion of the metabolic by-products from the gel. In U.S.
Patent No. 5,635,609, the encapsulation art described involves one esterified polysaccharide
(i.e., alginate) and one polyamine (i.e. chitosan) whereby the outer surface membranes
are formed through covalent amide bonds. U.S. Patent No. 4,439,488 teaches a process
of encapsulating pheromone whereby the biological agents are dissolved or dispersed
in an aqueous paste of a gel-forming polyhydroxy polymer. By adding boric acid to
an aqueous solution at alkaline pH, the paste transforms into a gel thereby entrapping
the agents in a protective matrix.
Japanese patent S 60-252403 describes a method of forming sprayable,
slow release pheromone agent obtained by emulsification co-polymerization. In Japanese
patent H-9-1244-08, the outer surface of the delivery system (i.e., synthetic resin
or inorganic substance) is coated by a waterproof material. The waterproof agent
can be a silicon, fluorine, or paraffinic hydrocarbon type material.
Additional vehicles for delivery of the pheromone composition of the
present invention include impregnating hollow fibres or twist-ties with a pheromone
and then physically attaching the fibres or ties to plants to be protected from
insect infestation. This process is labor-intensive and is suitable for protecting
small areas, for instance orchards. Another example of a delivery system is plastic
laminate flakes that have been impregnated with pheromone. Plastic laminate flakes
are dispensed to forests by aerial application, and require special devices for
All parts, percentages and ratios are by weight unless otherwise specified.
Verfahren zur Stabilisierung eines Insektenpheromons, umfassend Bereitstellung
einer Zusammensetzung, wobei die Zusammensetzung ein Pheromon und 2,2'-Methylenbis(6-t-butyl-p-kresol)
Verfahren nach Anspruch 1, wobei die Zusammensetzung im voraus für ein bestimmtes
Schadinsekt ausgewählt wird.
Verfahren nach Anspruch 1 oder 2, wobei die Zusammensetzung weiterhin einen
Verfahren nach einem der Ansprüche 1 bis 3, wobei die Zusammensetzung weiterhin
zusätzliche Stabilisatoren umfasst, die aus der Gruppe bestehend aus nickel- und
schwefelhaltigen Quenchern und Hydroperoxid/Peroxid-Fängern ausgewählt sind.
Verfahren nach einem der Ansprüche 1 bis 4, wobei die Zusammensetzung weiterhin
UV-Blocker umfasst, die aus der Gruppe bestehend aus Ruß und Titandioxid ausgewählt
Verfahren nach einem der Ansprüche 1 bis 5, wobei die Zusammensetzung weiterhin
zusätzliche Antioxidantien umfasst, die aus der Gruppe bestehend aus sterisch gehinderten
Phenolen, Bisphenolen, Aminophenolen, sekundären aromatischen Aminen, Hydroxybenzylverbindungen,
Alkyl- und Arylthioethern, Thiobisphenolen, Phosphiten, Phosphoniten und Zinkthiocarbamaten
Insektenpaarung störende Zusammensetzung, die ein Insektenpheromon und 2,2'-Methylenbis(6-t-butyl-pkresol)
in einer zur Stabilisierung des Insektenpheromons wirksamen Menge umfaßt.
Mikrokapsel, die die Insektenpheromonzusammensetzung nach Anspruch 7 umfaßt.
Verfahren zur Bekämpfung eines Schadinsekts, umfassend Aufbringen der Zusammensetzung
nach Anspruch 7 in einer Menge, die zur Hemmung oder Störung der Paarung von Schadinsekten
wirksam ist, in eine zu schützende Umgebung.
Verfahren zur Bekämpfung eines Schadinsekts nach Anspruch 9, wobei die die Insektenpaarung
störende Zusammensetzung in einer Mikrokapsel eingekapselt ist.
A method of stabilizing an insect pheromone comprising providing a composition,
said composition comprising a pheromone and 2,2'-methylenebis (6-t-butyl-p-cresol).
The method of claim 1, wherein the composition is preselected for a particular
The method of claim 1 or 2, wherein the composition further comprises a UV absorber.
The method of any of claims 1 to 3, wherein the composition further comprises
additional stabilizers selected from nickel and sulfur containing quenchers and
The method of any of claims 1 to 4, wherein the composition further comprises
UV blockers selected from the group consisting of carbon black and titanium dioxide.
The method of any of claims 1 to 5, wherein the composition further comprises
additional aminophenols, secondary aromatic amines, hydroxybenzyl compounds, alkyl
and arylthioethers, thiobisphenols, phosphites, phosphonites, and zinc-thiocarbamates.
An insect mating disruption composition comprising an insect pheromone and 2,2'-methylenebis(6-t-butyl-p-cresol)
in an amount effective to stabilize the insect pheromone.
A microcapsule comprising the insect pheromone composition of claim 7.
A method of controlling an insect pest comprising applying the composition of
claim 7 to an environment to be protected in an amount effective to inhibit or disrupt
mating of insect pests.
The method of controlling an insect pest of claim 9, wherein the insect mating
disruption composition is encapsulated in a microcapsule.
Procédé pour stabiliser une phéromone d'insecte comprenant le fait de se procurer
une composition, ladite composition comprenant une phéromone et du 2,2'-méthylènebis(6-t-butyl-p-crésol).
Procédé selon la revendication 1, dans lequel la composition est présélectionnée
pour un insecte nuisible particulier.
Procédé selon la revendication 1 ou 2, dans lequel la composition comprend en
outre un absorbeur UV.
Procédé selon l'une quelconque des revendications 1 à 3, dans lequel la composition
comprend en outre des stabilisants supplémentaires choisis parmi les extincteurs
contenant du nickel et du soufre et les épurateurs d'hydroperoxyde/peroxyde.
Procédé selon l'une quelconque des revendications 1 à 4, dans lequel la composition
comprend en outre des anti-UV choisis dans le groupe constitué par le noir de carbone
et le dioxyde de titane.
Procédé selon l'une quelconque des revendications 1 à 5, dans lequel la composition
comprend en outre des antioxydants supplémentaires choisis dans le groupe constitué
par les phénols à empêchement stérique, les bisphénols, les aminophénols, les amines
aromatiques secondaires, les composés hydroxybenzyle, les alkyl- et arylthioéthers,
les thiobisphénols, les phosphites, les phosphonites, et les thiocarbamates de zinc.
Composition destinée à perturber l'accouplement des insectes comprenant une
phéromone d'insecte et du 2,2'-méthylènebis(6-t-butyl-p-crésol) en quantité efficace
pour stabiliser la phéromone d'insecte.
Microcapsule comprenant la composition de phéromone d'insecte selon la revendication
Procédé pour lutter contre un insecte nuisible comprenant l'application de la
composition selon la revendication 7 à un environnement qui doit être protégé en
quantité efficace pour inhiber ou perturber l'accouplement des insectes nuisibles.
Procédé pour lutter contre un insecte nuisible selon la revendication 9, dans
lequel la composition destinée à perturber l'accouplement des insectes est encapsulée
dans une microcapsule.