Composition and method for influencing the location of wood-inhabiting beetles

Abstract

The invention relates to dispersions containing polymer particles or polymer-based nanoaggregates or microaggregates which are mixed with at least one semiochemical for attracting or repelling a beetle species inhabiting predetermined wood or for attracting a predator of said beetle species and are optionally loaded with further auxiliaries and additives, with the proviso that the polymer has at least one polymer-specific parameter selected from the group of the glass transition temperature, the crystallite melting temperature, the supramolecular interactions, the humidity, the effect of light or the targeted degradability, which changes in a predetermined temperature range and / or moisture range such that the semiochemical contained in the particles is released or that the polymer or the polymer-based nanoaggregate or microaggregate is enzymatically or hydrolytically degraded such that the semiochemical contained in the particles is released. The dispersions can be used in particular for controlling bark beetles.

Description

[0001] Description

[0002] Composition and method for influencing the location of wood-dwelling beetles

[0003] The invention relates to the field of controlling the location of wood-dwelling beetles by means of messenger substances and compositions suitable therefor.

[0004] With over 380,000 currently known species, beetles (Coleoptera) are the world's largest order of insects. Beetles inhabit most habitats on Earth, exploiting virtually every organic food source.

[0005] Beetles generally only come into the public eye when they affect people's lives. This is most often the case when they appear as pests, nuisances, or even beneficial organisms.

[0006] When storing food or growing crops in monocultures, conditions occasionally favor the mass proliferation of certain beetle species. Examples of stored product pests, primarily in company storage facilities, include grain and rice weevils, while flour beetle larvae are also frequently found in households. Agricultural pests include the Colorado potato beetle, the rapeseed pollen beetle, and the western corn rootworm. Many beetles are plant pests, attacking a wide variety of plants, including trees, including deadwood. The native house longhorn beetle (Hylotrupes bajulus) can attack buildings. The beetle's larvae live in built-up coniferous wood, for example, in roof trusses. The common woodworm (Anobium punctatum), also known as the woodworm, also lives in dead wood. Examples of tree pests include the Asian longhorn beetle (Anoplophora glabripennis).Bark beetles are among the most significant pests of living wood. Among them is the European spruce bark beetle (Ips typographus), which can cause significant damage, particularly in cultivated spruce forests. Bark beetles are also dangerous in natural forests. The mountain pine beetle (Dendroctonus ponderosae), for example, has considerable destructive potential. Damage caused by beetle infestations has significant economic impacts on agriculture and forestry.

[0007] Many beetles play an important role in the natural ecosystem. Humans also benefit from some species. Among the most important of these are predatory beetles, such as ground beetles, rove beetles, and especially ladybugs. These species consume harmful insects, mites, and slugs in agriculture and forestry. Certain ladybug species are bred in large numbers for use against agricultural pests. These leaf- and scale-eating beetles are also useful in gardens.

[0008] Many beetles communicate using messenger substances. These influence the behavior of individuals within a population. Messenger substances are chemicals that serve for signal transmission or chemical communication. They can exert their effects within an organism, between individuals of a species, or between different species. Messenger substances belong to a wide variety of chemical compound classes. Many of these are peptides, steroids, amino acid derivatives, isoprene derivatives, terpene derivatives, aldehydes such as benzaldehyde or salicylaldehyde, or acids such as benzoic acid.

[0009] The following description of the invention is based on the example of the bark beetle. However, the concept of this invention can easily be transferred to other wood-dwelling beetles that communicate via messenger substances. The bark beetle (known in Germany as the "spruce bark beetle" especially when it infests spruce trees (there are currently over 6,000 known bark beetle species, all subspecies of the weevil)) causes extreme losses of forest area worldwide. Since spruce has been planted as a monoculture on a large scale for around 200 years, particularly in Central Europe, there is currently an intensive infestation, particularly in the Harz Mountains, the Ore Mountains, and the Bavarian Forest, but now also in Austria, Italy, and the Czech Republic. Due to climate change (warming, less precipitation, hurricanes with a lot of damaged wood), this development has increased almost exponentially in the last 20 years. This is particularly the case in areas with poorly accessible forest areas (e.g.In steep slopes of the Alps, there is almost no way to remove damaged wood in time to prevent the further spread of the bark beetle. However, forests in the Alps play a crucial role as protective forests (protected forests). Without forests, billions of euros must be invested to prevent mudslides, avalanches, and rockfalls, and to keep valleys accessible and protect the people living there.

[0010] One measure to combat bark beetles involves setting traps. However, traps are not suitable for significantly reducing a bark beetle population. Traps are primarily used to register infestations. The use of killing traps is also questionable for all beneficial insects. The widespread use of insecticides, such as the approved products Fastac Forst or Karate Forst, is prohibited, as they also kill enemies of the bark beetle, such as the ant beetle. Furthermore, only a very small proportion of insecticides are effective against the bark beetle (<0.1%). The majority of the chemicals are blown away during spraying, drip from the bark, are emitted as dust, or are released too early. The currently most successful way to combat bark beetle infestation is to remove all damaged wood (see https: / / www.rnd.de / -wissen / borkenkafer-2019-wie-kann-man-ihn-bekampfen-und-warum-ist-er-so- gefahrlich-DKLHHCN4TI43Y3J7PSRR4B4YHA.html).If regional removal with a safe distance is not entirely possible, the stocks of felled timber are irrigated, kept moist, or treated with insecticides. However, efficient removal is often not possible in cases of massive infestation or after storm damage / snow breakage, especially on steep slopes or in areas with few access roads, such as in the low mountain ranges and especially in the Alps and other mountain ranges.

[0011] Another method for controlling bark beetles involves the use of messenger substances. The bark beetle (as a prominent example of other proboscideans, such as the copperplate engraver), especially the "spruce bark beetle," which attacks Norway spruce in Central Europe, works with a mixture of messenger substances (modified spruce building blocks, pheromones, and other information chemicals) that are used to attract or repel other bark beetles. A healthy spruce can fight a bark beetle by using resin. When spruce trees are weakened by drought, heat, damage from storms / hurricanes, or snow damage, their defenses are reduced. If the bark beetle has massively multiplied locally, it can also successfully infest healthy spruce trees. As is so often the case in nature, the messenger method is used very intelligently for this purpose.Initial infestations of a spruce tree release mixtures of messenger substances that attract additional bark beetles (e.g., verbenol, ipsenol, or other terpenes). Even healthy spruce trees can no longer resist an infestation of hundreds or more bark beetles. Afterward, the spruce's "occupiers" switch mode and release new mixtures of messenger substances that signal that the tree is "full." Additional bark beetles then infest surrounding spruce trees. This is how "nests" form. A new bark beetle population can then travel distances of 500 meters, and sometimes (with favorable winds) even several kilometers, thus killing entire forest areas in the immediate vicinity of the "nests" and simultaneously forming new "nests" farther away. The bark beetles begin to migrate when average air temperatures reach 16.5°C; however, with suitable sunlight, a migration can begin earlier in some locations.In warm and dry years, up to three populations, and thus bark beetle flights, can develop, causing incredible damage and devastation, almost like an "atom bomb." Conventional forestry cannot remove the infested wood quickly enough, even in easily accessible regions—not to mention low mountain ranges and the Alpine regions.

[0012] The messenger substances of the bark beetles also attract enemies (such as the ant beetle, the scorpion beetle, and the chalcid wasp; there are approximately 300 natural enemies of the bark beetle). However, when the population multiplies rapidly, the enemies are unable to counteract them.

[0013] The bark beetle's messenger substances can be deployed in traps. However, these have a much too targeted effect. Even the deployment of hundreds of thousands of traps in Norway and Sweden only managed to slow the bark beetle outbreaks. Depending on the trap and the combined use of insecticides, the bark beetle's predators are also killed. Furthermore, the messenger substances are highly volatile and therefore evaporate quickly. They then have to be repeatedly reapplied. Current studies describe the hanging of "scent bags" to create a "firewall" (see https: / / deutsch.radio.cz / -tschechische- wissenschaftler-entwickeln-chemiefreie-impraegnierung-gegen-8746509). The authors themselves write that this is unlikely to be successful in extensive forests.

[0014] A wide variety of strategies and measures have already been used to combat the bark beetle. However, these are complex or only partially effective and therefore require further improvement.

[0015] US 2017 / 0354596 A1 describes a nanoemulsion comprising water as a dispersant and a disperse oil phase. The oil phase contains at least one hydrophobic active ingredient combined with a hydrophobic polymer that may be biodegradable. The disperse phase also contains an amphiphilic chitosan derivative that is aggregated with a fatty acid through ionic interaction. The nanoemulsions can be used to produce liquid formulations for medical applications. Halahlah, A. et al., in an article entitled "Synthesis and characterization of inclusion complexes of rosemary essential oil with various betacyclodextrins and evaluation of their antibacterial activity against Staphylococcus aureus," J. Drug Deliv. Sci. Tec., Vol. 65, 102660 (2021), describe the encapsulation of selected oils for antibacterial use.

[0016] In an article by El-Said Azzazy, HM et al., entitled “Essential oils extracted from Boswellia sacra Oleo Gum resin loaded into PLGA-PCT Nanoparticle: Enhanced Cytotoxic and Apoptoxic Effects against Breast Cancer Cells”, ACS Omega, Vol. 8, No. 1 , pp. 1017-1025 (2023), the influence of selected oils in PLGA-PCT nanoparticles on breast cancer cells is revealed.

[0017] In an article entitled “Preparation and evaluation of attractive microspheres for control of Agrilus planipennis faimaire,” J. Environ Sci. Health B, Vol. 58, No. 2, pp. 131-138 (2023), Li, YY describes the use of selected microspheres to attract a beetle species.

[0018] The object of the present invention is to provide a method and a composition suitable therefor in order to specifically influence the location of beetles, in particular bark beetles.

[0019] Research on beetles, such as weevils and especially bark beetles, has provided knowledge about which messenger substances and combinations of them have which effect at which stage of development of the larvae / beetles and for which beetles. This means that the attraction or repulsion of conspecifics, or the attraction of enemies, can be specifically controlled.

[0020] Research into polymer-based systems, for example in the form of micelles, vesicles, lipid-solid nanoparticles, lipid-polymer hybrid nanoparticles, nanoparticles, nanospheres, microparticles, microspheres, films, foils, or molded bodies, has provided knowledge about which polymers are suitable as carriers for active substances and can release these substances, for example, depending on temperature, humidity, pH, sunlight, the presence of enzymes, or salts. These polymer-based systems can be co-formulated with other polymeric excipients, inorganic excipients, organic substances such as oils or other low-molecular-weight substances, as well as bio-based substances (such as lignin or cellulose).

[0021] Nanomedicine and pharmaceuticals have provided knowledge of how to package mixtures of active substances ("cocktails"). Furthermore, knowledge exists about when encapsulated substances are released and how to achieve slow release ("delayed release").

[0022] The present invention combines existing knowledge in an inventive and novel way to create a groundbreaking new method for the targeted control of the location of beetles, including their larval stages, as well as the attraction of beetle predators. This allows for effective control of bark beetles and related weevils, in particular.

[0023] The present invention relates to dispersions containing water or biodegradable aprotic-polar solvents as dispersants and polymer particles or polymer-based nano- or microaggregates as disperse phase, which are loaded with at least one messenger substance for attracting or repelling a predetermined wood-dwelling beetle species or for attracting a predator of this beetle species and optionally with further auxiliaries and additives, with the proviso that the polymer or the polymer-based nano- or microaggregate has at least one polymer-specific parameter selected from the group of the glass transition temperature, the crystallite melting temperature, the supramolecular interactions, the air humidity or the targeted degradability, which changes in a predetermined temperature range and / or humidity range and / or upon exposure to light, so that the messenger substance contained in the particles is released,or that the polymer or the polymer-based nano- or microaggregate is degraded enzymatically, hydrolytically or photochemically, so that the messenger substance contained in the particles is released.

[0024] For the purposes of this description, dispersions are understood to be heterogeneous mixtures of at least two substances that are insoluble or hardly soluble in one another or chemically bonded to one another. One of these substances is water or a biodegradable aprotic-polar solvent, such as cyrene. One or more substances are distributed within it as a so-called disperse phase. Water or the biodegradable aprotic-polar solvent forms a continuous phase, the so-called dispersion medium. Depending on the physical state of the dispersion medium and the disperse phase, the dispersions according to the invention can occur as emulsions (liquid / liquid) or as suspensions (liquid / solid). Polymer particles or polymer-based nanoparticles or microparticles can occur as the disperse phase.The latter are polymer-based micelles, polymer-based vesicles, lipid-solid nanoparticles, lipid-polymer hybrid nanoparticles, polymer-based nanospheres or nanocapsules as well as polymer-based microspheres or microcapsules.

[0025] In the context of this description, targeted degradability means that the polymer or polymer-based nano- or microaggregate is enzymatically or hydrolytically degradable, resulting in the release of the messenger substance contained in the particles or aggregates. However, release can also occur when the Tg / Tm is exceeded, or when appropriate swelling occurs, or the LOST (Lower Critical Solution Temperature) is exceeded.

[0026] After application and evaporation of the dispersant, the dispersions according to the invention are generally present as films or dried polymer particles or dried polymer-based nano- or microaggregates on plant parts or on the soil. For the purposes of the present description, beetles are understood to mean the adult animals (imago) including their larvae and pupae. The dispersion according to the invention is preferably used to influence the location of the

[0027] For the purposes of this description, "beetles" are understood to mean the adult beetles (imago), including their larvae and pupae. The dispersion according to the invention is preferably used to influence the location of the adult beetles and / or their predators.

[0028] The dispersions according to the invention are generally applicable to all wood-dwelling beetle species that communicate via messenger substances (i.e., are attracted or repelled thereby) or whose predators are attracted by means of messenger substances.

[0029] The dispersions according to the invention are preferably used to attract wood-dwelling beetles, which are beneficial or pests, or to attract predators of the beetle pests. The dispersions according to the invention are also preferably used to repel wood-dwelling beetles, which are pests. These are thereby driven to targeted collection points or "firebreaks" are created that the beetles cannot overcome.

[0030] The dispersions according to the invention can contain several messenger substances that, for example, attract beetle pests and simultaneously their predators. In addition to the messenger substances, the dispersions according to the invention can also contain other ingredients with which, for example, beetle pests can be destroyed, such as insecticides.

[0031] The dispersions according to the invention are preferably used to influence the location of beetles living on, at, or in trees, or on or in the ground area of ​​trees. Tree-dwelling beetles are preferably weevils, particularly preferably bark beetles, and most particularly preferably spruce bark beetles (Ips typographus), copperplate engraver beetles (Pityogenes chalcographus), large and small wood bark beetles, oak bark beetles, striped timber bark beetles (Trypodendron lineatum), or black timber bark beetles (Xyleborus germanus).

[0032] The dispersions according to the invention can be in the form of suspensions (solid particles or aggregates dispersed in an aqueous dispersion medium) or emulsions (liquid particles or aggregates dispersed in an aqueous dispersion medium). The polymer particles or the polymer-based aggregates are generally present as nano- or microparticles or aggregates. These are therefore particles or aggregates composed of finely dispersed polymers or finely dispersed components, in particular of finely dispersed polymeric solids or of finely dispersed polymeric hydrogels. The dispersions according to the invention can also be present in "green" solvents, e.g., Cyrene, produced from cellulose.

[0033] The dispersions according to the invention can be prepared by precipitation of the polymers, preferably by nanoprecipitation. For this purpose, the polymers can be dissolved in a water-miscible solvent, such as acetone. This solution is added dropwise to a hydrophilic dispersing medium, preferably with vigorous stirring. This can promote the production of smaller particles. The polymer is deposited in the dispersing medium in finely divided form.

[0034] Alternatively, the dispersions according to the invention can also be produced by suspending or emulsifying polymer particles. For this purpose, the polymers can be dissolved in a water-immiscible solvent, such as dichloromethane or ethyl acetate. This solution is combined with a hydrophilic dispersing medium, preferably forming two liquid phases. This mixture is then suspended or emulsified by applying energy, preferably by ultrasonication. In addition to the polymer, one or more messenger substances and / or one or more auxiliaries and additives can be present during its precipitation or dispersion in the dispersing medium. Alternatively, these messenger substances and / or auxiliaries and additives can be added after the polymer has been precipitated or dispersed in the hydrophilic liquid.

[0035] In the context of this description, nanoparticles or nanoaggregates are understood to mean particles or aggregates which have diameters (z-average) of less than 1000 nm as determined by dynamic light scattering.

[0036] Preferred particle diameters (z-average) for nanoparticles or nanoaggregates are in the range of less than or equal to 500 nm, particularly preferably between 30 and 500 nm, very particularly preferably between 40 and 250 nm and in particular between 50 and 200 nm.

[0037] In the context of this description, microparticles or microaggregates are understood to mean particles or aggregates which have diameters (z-average) of at least 1 pm as determined by dynamic light scattering.

[0038] Preferred particle diameters (z-average) for microparticles or microaggregates are in the range of greater than or equal to 5 pm, particularly preferably between 10 and 200 pm, and most preferably between 20 and 50 pm.

[0039] For the purposes of this description, particle diameters up to 10 pm are determined by dynamic light scattering (DLS) using a Malvern Zetasizer Nano-ZS (Malvern Instruments, Worcestershire, United Kingdom). The intensity-weighted mean diameter (z-average) was determined using cumulant analysis of the correlation function (ISO13321, ISO22412). Larger particles with diameters greater than 10 pm can be determined using visual methods, for example, microscopy. For particle sizes in the nanorange, light scattering or electron microscopy can be used. The shape of the polymer particles or aggregate particles can be arbitrary, for example, spherical, ellipsoidal, or irregular. The polymer particles can also form aggregates of several primary particles. The particles or aggregates in the dispersions according to the invention are preferably in the form of nanoparticles or nanoaggregates.

[0040] The dispersions according to the invention can be further characterized by their polydispersity index (or PDITG). The polydispersity index of the particle size distribution (PDITG) indicates the breadth of the particle size distribution. Values ​​between 0 (monodisperse) and 1 (polydisperse) can be assumed. The PDI T For the purposes of this description, the G-value is determined by dynamic light scattering (DLS) using a Malvern Zetasizer Ultra (Malvern Instruments, Worcestershire, United Kingdom). The PDITG was determined using cumulant analysis of the correlation function.

[0041] The PDI T The G-value of the particle size distribution of the nano- and microparticles or nano- or microaggregates used according to the invention typically ranges between 0.05 and 0.8, preferably between 0.1 and 0.7 and particularly preferably between 0.05 and 0.6.

[0042] Nanoparticles or nanoaggregates are particularly preferably used according to the invention. These have diameters (z-average) determined by DLS between 40 and 250 nm, most preferably between 50 and 200 nm, and a PDITG between 0.05 and 0.2.

[0043] The dispersions according to the invention may contain stabilizers that prevent or delay sedimentation of the dispersed phase. Surfactants and / or protective colloids can be used as stabilizers. Such measures are known to those skilled in the art.

[0044] The dispersions according to the invention may contain oils as additives. Examples include olive oil, sunflower oil, rapeseed oil, or other vegetable or animal oils. Such measures are known to those skilled in the art.

[0045] In the dispersions according to the invention, polymers are used as carriers for the messenger substances. The messenger substance is intended to be released from the micro- or nanoparticle only at a user-selected temperature and / or ambient humidity and / or upon exposure to light. The release can be controlled by selecting the polymer, its degree of cross-linking, its molecular structure, or the additives. This polymer has at least one temperature-dependent or humidity-sensitive parameter that influences the rate of release of the messenger substance or messenger cocktail combined with the polymer. The temperature-dependent parameter can be adjusted, for example, by producing specially adapted copolymers with a tailored glass transition temperature, melting temperature, crystallinity, or hydrophobic / hydrophilic balance, or by adjusting the additives used or the manufacturing method.

[0046] Preferably, the polymer should be biodegradable at the site of use, for example, in (forest) soil. However, polymers that are stable for a longer period under the conditions of the site of use can also be used.

[0047] For the purposes of this description, biodegradable polymers are understood to be polymers that are compostable under the conditions of their place of use (temperature, humidity, UV-VIS radiation exposure, enzymes, bacteria). This means that the polymers must be degraded to at least 60% by weight within 180 days (cf. ASTM D-6400). The polymers used as carriers in the dispersions according to the invention can belong to a wide variety of compound classes. The polymers used according to the invention are basically macromolecules composed of one or more structural units, the so-called repeating units. In many cases, a polymer consists of non-identical macromolecules; the type and number of repeating units and the molecular mass generally vary.

[0048] The polymers used according to the invention can be synthetic or semi-synthetic in nature or they can also be polymers produced by living organisms (biopolymers).

[0049] The biopolymers used according to the invention include proteins or polysaccharides, such as cellulose, starch or chitin.

[0050] The synthetic polymers used according to the invention include polycondensates, such as polyesters or polyamides, or proteins, or polymers produced from ethylenically unsaturated monomers, such as poly(meth)acrylic acid or poly(meth)acrylates.

[0051] The semi-synthetic polymers used according to the invention include polymers produced by further processing of biopolymers, for example starch derivatives.

[0052] Polymers used according to the invention can be used in their pure form or in the form of polymer blends. The latter include, in particular, supramolecular polymers, i.e., polymers whose building blocks are held together not by covalent bonds, but by comparatively weak intermolecular bonds. These bonds include hydrogen bonds, ionic bonds, metal-ligand interactions, van der Waals interactions, or hydrophobic interactions. These intermolecular bonds can be easily broken at elevated temperatures and can also quickly reform upon cooling. The temperature at which intermolecular bonds break can be adjusted by selecting the type and amount of these bonds.

[0053] In general, the polymers used according to the invention are organic polymers, i.e. polymers composed of monomers containing carbon atoms.

[0054] The polymers used according to the invention can be thermopastes, thermosets, elastomers, or thermoplastic elastomers. The polymers can be linear, branched, or cross-linked. Thermoplastics are preferably used.

[0055] Atactic polymers can be used. These are polymers with a high degree of branching or random copolymers. In the solid state, these form amorphous, glassy structures with a frozen conformation of the molecules. Interlocking and entanglement of the polymer chain molecules with each other lead to a "mechanical bond" between the chains. Intermolecular and intramolecular secondary bonding occurs only in a few places.

[0056] Linear polymers with a regular structure, low branching, and stereoregularity can also be used. Such polymers have a (semi-)crystalline structure in the solid state due to regions of dense chain packing. The resulting crystallites are formed by more or less regular folding of one or more molecular chains. Amorphous structures lie between them. Several crystallites can form a superstructure, e.g., spheroliths. The type and arrangement of (functional) residues of the repeating units influence or determine the crystallinity and the strength of the secondary valence bonds. Particularly strong intermolecular interactions occur when the residues of the repeating units allow the formation of hydrogen bonds. Finally, the polymers used according to the invention can be loosely cross-linked polymers (elastomers), including hydrogels.These are not meltable without decomposition or they are reversibly meltable as thermoplastic elastomers.

[0057] Among the preferred polymers are biodegradable polymers. These include polymers that can be decomposed by microorganisms such as fungi or bacteria, or by enzymes, under the conditions prevailing at the site of use. Degradation occurs primarily through oxidation and hydrolysis to the decomposition products water and carbon dioxide, or to methane and biomass.

[0058] Biodegradable polymers usable according to the invention may be biopolymers or may be of petrochemical origin.

[0059] Preferred polymers are polyesters, polyamides or starches.

[0060] Particularly preferred polymers are approved for environmental applications. These include polylactides, dextrans, alginates, starches, modified starches, polyhydroxyalkanoates, or biodegradable polyesters or polyamides.

[0061] Polyhydroxyalkanoates (PHAs) include naturally occurring, water-insoluble and linear biopolyesters. PHAs can be thermoplastics or elastomers. The melting point of these materials generally ranges from 40 to 180 °C, but can be adjusted outside these limits, for example, by incorporating comonomers. PHA can be synthesized as short-chain PHA with 3 to 5 carbon atoms, as medium-chain PHA with 6 to 14 carbon atoms, or as long-chain PHA with 15 or more carbon atoms. Depending on the microorganism and cultivation conditions, homo- or copolyesters can be produced with a wide variety of hydroxycarboxylic acids.Zu den bevorzugt im Rahmen der vorliegenden Erfindung eingesetzten PHA zählen Poly(3-hydroxypropionat), Poly(3-hydroxybutyrat), Poly(3-hydroxyvalerat), Poly(3- hydroxyhexanoat), Poly(3-hydroxyheptanoat), Poly(3-hydroxyoctanoat), Poly(3- hydroxynonanoat), Poly(3-hydroxydecanoat), Poly(3-hydroxyundecanoat), Poly(3- hydroxydodecanoat), Poly(3-hydroxytetradecanoat), Poly(3-hydroxypentadecanoat), Poly(3-hydroxypropionat-co-3-hydroxybutyrat), Poly(3-hydroxypropionat-co-4- hydroxybutyrat), Poly(3-hydroxybutyrat-co-4-hydroxybutyrat), Poly(3-hydroxybutyrat- co-3-hydroxyhexanoat), Poly(3-hydroxybutyrat-co-3-hydroxyvalerat), und Poly(3-hydroxybutyrat-co-3-hydroxyvalerat-co-3-hydroxyhexanoat).

[0062] Polylactides (PLA) include polymers composed of chemically bonded lactic acid monomers. PLA is a thermoplastic. PLA is typically tailored to the specific application through compounding. The resulting "PLA blends" typically consist of PLA, other biodegradable plastics, and additives. PLA can also be modified by copolymerization with other monomers, for example, to achieve a desired glass transition temperature.

[0063] The dextrans used in the invention are high-molecular-weight, branched, neutral biopolysaccharides. Dextrans consist primarily of glucose units. Natural dextrans have molecular weights between 10,000 and 50,000,000 Da. Dextrans can also be modified by copolymerization with other monomers, for example, to achieve a desired glass transition temperature.

[0064] The alginic acids used in the invention are biopolymers formed by brown algae or bacteria. The salts of alginic acid are called alginates. These are polysaccharides consisting of the uronic acids α-L-guluronic acid (GulUA) and β-D-mannuronic acid (ManUA). These are linked by 1,4-glycosidic bonds in varying ratios to form linear chains, in which homopolymeric regions are formed in which mannuronic acid or guluronic acid are present as blocks. Alginates tend to form gels by incorporating divalent ions, such as calcium ions, into the copolymer blocks.

[0065] The starches used in the invention are polysaccharides consisting of α-D-glucose units. Enzymes such as α- or β-amylases can break down starch, resulting in dextrins or disaccharides. When exposed to heat, starch can physically bind, swell, and gelatinize with many times its own weight in water. Starches can be linear or branched. Modified starches can also be used within the scope of the present invention. These are starch products obtained by physical, enzymatic, or chemical processes.

[0066] These include natural or degraded starches that have been converted into their respective derivatives through polymer-analogous reactions. Examples include acid-treated starches, alkali-modified starches, enzymatically modified starches, oxidized starches, acetalized starches, or hydroxypropyl starches.

[0067] Other polymers preferably used according to the invention include polyesters, polyesteramides or polyamides.

[0068] Preferred polyesters are derived from aliphatic dicarboxylic acids and alkylene glycols or are copolyesters derived from aromatic and aliphatic dicarboxylic acids and alkylene glycols. Examples are poly(butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS), poly(ethylene adipate-co-terephthalate) and polyethylene succinate.

[0069] Preferred polyesteramides are derived from aliphatic dicarboxylic acids, alkylene glycols, and aliphatic diamines or aliphatic lactams. An example is a polyesteramide derived from e-caprolactam, adipic acid, and 1,4-butanediol. Preferred polyamides are derived from aliphatic dicarboxylic acids and aliphatic diamines, or from aliphatic aminocarboxylic acids or aliphatic lactams.

[0070] Polymers preferably used according to the invention have a specifically adjusted glass transition temperature. This can be achieved by selecting the type and amount of monomers used in the polymerization. Thus, the glass transition temperatures of copolymers can be estimated using the Fox equation. This is an equation describing the glass transition temperature of mixtures with multiple components as a function of the respective mass fractions of these components. This procedure is known to those skilled in the art.

[0071] Polymer blends preferably used according to the invention are characterized in that their polymeric components are held together by intermolecular bonds that dissolve at a predetermined temperature. These polymer blends include those containing polymers capable of forming hydrogen bonds, ionic bonds, or metal-ligand interactions.

[0072] Other polymers preferably used according to the invention can be degraded enzymatically, hydrolytically, or photochemically. This degradation releases the messenger substance contained in the polymer particle. The enzymes required for enzymatic degradation can be added to the dispersion according to the invention, be present at the point of application of the dispersion (e.g., fungal enzymes), or be applied together with the dispersion at the point of application. Hydrolytic degradation can be brought about by adjusting the required hydrolysis conditions, for example, by adjusting a specific pH. For example, the dispersions according to the invention can contain additives that release an acid or a base. These additives can be present in the dispersion according to the invention or can be applied together with the dispersion at the point of application.Due to the slow degradation, the messenger substance contained in the polymer particles can be released over a longer period of time. Temperature control of the degradation or triggering of degradation at a certain temperature is not necessary with this variant, although it is not excluded.

[0073] The polymer blends can be provided with inorganic fillers, for example with silica, calcium or magnesium compounds, with organic fillers such as oils, e.g. olive oil, as well as with bio-based components such as lignin or cellulose.

[0074] According to the invention, messenger substances are combined with polymers as carriers. The carrier is selected such that the messenger substance is only released at a user-selected temperature and / or ambient humidity or at a corresponding solar radiation intensity, or is released over a longer period of time.

[0075] For the purposes of this description, a messenger substance is understood to be a chemical compound that serves to facilitate communication between organisms (semiochemical). Semiochemicals are generally divided into pheromones and allelochemicals: Pheromones facilitate communication between organisms of one species (intraspecific), while allelochemicals transmit information between organisms of at least two species (interspecific).

[0076] Allelochemicals are divided into allomones, which benefit the sender, kairomones, which benefit the receiver, and synomones, which benefit both.

[0077] Semiochemicals can be classified according to their effect on the recipient. For example, pheromones that elicit only a behavioral response in the recipient are called releaser pheromones. Pheromones that cause a significant physiological change in the recipient are called primer pheromones.

[0078] A further classification can be made based on the function of the pheromone. For example, there are aggregation pheromones, which cause bark beetles, for example, to gather to attack a tree. Sex pheromones serve to attract mates. Aphrodisiac pheromones serve as sexual stimulation and can also act as herbivore toxins. Alarm pheromones warn of predators, and marking and trailing pheromones mark territories and trails.

[0079] All of these messenger substances can be used within the scope of the present invention, depending on the intended control of the location.

[0080] According to the invention, systems based on preferably biodegradable polymer systems can be used which release suitable messenger substances in a delayed manner in order to attract forest pests, such as weevils, in particular bark beetles, into decoy wood in order to destroy them there, for example by attracting natural enemies, and / or by co-formulating the messenger substances with insecticides, and / or by removing the bark.

[0081] According to the invention, systems based on preferably biodegradable polymer systems can also be used, which release suitable messenger substances with a delay in order to lure forest pests, such as weevils, in particular bark beetles, into decoy wood, so that they can be made harmless by spatially removing the decoy wood.

[0082] Furthermore, according to the invention, systems based on preferably biodegradable polymer systems can be used that release suitable messenger substances with a delay to keep forest pests, such as weevils, especially bark beetles, away from certain habitats. Thus, by releasing defensive pheromones, "firebreaks" can be created that delay or prevent the spread of forest pests, or forest pests can be guided to decoy wood, traps, or predators by releasing defensive pheromones.

[0083] Accordingly, according to the invention, systems based on preferably biodegradable polymer systems can be used, which release suitable messenger substances with a delay in order to attract beneficial insects, such as ladybirds, to a desired location in order to be able to use them there in a targeted manner.

[0084] The delayed release of the messenger substance is suitable for providing an effective means of controlling the location of beetles throughout the entire season. By controlling the temperature or simultaneously exploiting sensitivity to humidity or light exposure during the release of the messenger substance, activation can be limited to times when the use of a messenger substance is also appropriate. For example, it is known that bark beetles only become active (beetle flight) at an average air temperature of 16.5°C or higher; however, in some areas, strong sunlight can cause them to fly earlier.

[0085] The release behavior of the messenger substance can be adjusted by selecting the polymer, producing specially adapted copolymers with tailored glass transition temperature, melting temperature, crystallinity, hydrophobic / hydrophilic balance, or (bio)degradability, such as enzymatic degradation or hydrolysis. This can be supported by the appropriate addition of inorganic excipients, synthetic or bio-based excipients, or oils.

[0086] According to the invention, a specifically adaptable "messenger substance cocktail" can be applied. The messenger substances can be adapted regionally or adapted to the variations for different infestation periods (larvae, small beetles, adult beetles, sex) as well as to the infestation rounds (spring, summer, fall). The messenger substances can be specifically adapted to the respective habitat, for example, to different tree species such as spruce, pine, or larch.

[0087] The messenger substances can also be adapted to the regionally present or attractable beetle pests, e.g. ant beetles, bracken flies or chalcid wasps.

[0088] If necessary, the messenger substances can also be combined with essential oils.

[0089] The messenger substances can be used to stimulate beetle pests to infest decoy wood or to create firebreaks to prevent beetle infestation. The use of decoy wood is particularly useful in the early stages of a beetle infestation. The use of firebreaks is especially useful when the beetle infestation has already reached an acute stage and further spread must be prevented at all costs.

[0090] The dispersions according to the invention particularly preferably contain, as disperse phase, nano- or microaggregates which, in addition to the polymer, comprise at least one oil and a messenger substance which acts as an attractant or repellent for beetles, in particular for bark beetles.

[0091] The invention also relates to a method for influencing the location of wood-dwelling beetles by the use of messenger substances, the method comprising the following measures: i) providing the dispersions described above which contain messenger substances which attract the beetles and / or their predators or which repel the beetles, the dispersions containing polymer particles which release the messenger substances above a predetermined temperature or which are degraded enzymatically or hydrolytically or by exposure to light to release the messenger substances, and ii) applying the dispersions to a habitat in which the beetles are to be found or from which the beetles are to be kept away.

[0092] The messenger substances are preferably incorporated into nano- / microparticles, whereby these particles have been produced by nano- or microprecipitation, inverse nano- or microprecipitation, or by microfluidics or emulsification processes. However, other methods known to the person skilled in the art for producing suspensions or emulsions can also be used.

[0093] The dispersions are preferably in the form of aqueous suspensions of nano- or microparticles or micelles or vesicles or nanocapsules / nanospheres or microcapsules / microspheres and are particularly stabilized by surfactants and / or protective colloids.

[0094] The delayed release of the messenger substance (cocktail) can be achieved by adjusting the polymer matrix or the inorganic, bio-based, or oil-based additives. Release from dry particles, films, or aggregates thereof, or hydrogels preferably occurs at air temperatures or local temperatures on the bark or soil of 17 °C, preferably at 20 °C, particularly in the range of 25 °C to 30 °C, or between 30 and 45 °C in areas particularly exposed to sunlight.

[0095] The use of mixtures of particles with different release temperatures is also possible.

[0096] The dispersions can be applied to the habitats by spraying; alternatively, they can be applied by placing traps, containers, dispensers, molded bodies, 3D-printed parts, films, or foils containing the dispersions into the habitat. Application can be achieved by treating selected areas of a habitat or potential habitat for the beetles. However, extensive forest or park areas can also be treated.

[0097] In a selected variant of the method according to the invention, locations ("nests") where a beetle infestation has already occurred and where the beetle is still active are first identified. The dispersion according to the invention is then applied to these locations. Such locations can be identified, for example, using aerial image analysis.

[0098] Dispersions applied by spraying form films or aggregates / powders of polymer particles after application to the desired habitat and the evaporation of the dispersion medium. These can be continuous films or limited areas on which films or isolated precipitates of polymer particles have been deposited. These polymer films preferentially adhere to tree bark and / or leaves and / or are located in the ground area of ​​trees.

[0099] The invention therefore preferably relates to films or aggregates / powders of polymer particles on tree bark, leaves and / or in the ground area of ​​trees, which have been produced by spraying the dispersions according to the invention.

[0100] The dispersions are preferably applied to the habitats by spraying, for example, manually or mechanically using spraying devices. Mechanical application can be carried out by aircraft equipped with spraying devices, such as airplanes, helicopters, or drones. Mechanical application can also be carried out by land-based machines equipped with spraying devices, such as automobiles, tracked vehicles, or tractors.

[0101] Stable dispersions prepared in water or in biodegradable aprotic-polar solvents, such as suspensions or emulsions of nano- or microparticles or hydrogels, can be sprayed directly. Such dispersions are preferably stable for at least one week, preferably one month, especially for at least three months, ideally up to six months. Storage stability can be optimized by positive or negative surface charges of the polymer particles and by the use of additives or stabilizers. Alternatively, redispersion can be achieved by shaking, vibrating, or stirring.

[0102] The method according to the invention is particularly suitable for controlling bark beetles. For this purpose, messenger substances are selected that attract bark beetles and / or their predators or repel them.

[0103] The invention further relates to the use of the dispersions described above for attracting wood-dwelling beetles and / or their predators into a habitat or for repelling wood-dwelling beetles from a habitat.

[0104] The following examples serve to illustrate the invention. They are not intended to be limiting.

[0105] Materials

[0106] All chemicals and solvents were purchased from commercial suppliers and used without purification unless otherwise stated. Ethyl acetate and acetone (99+% extra pure) were purchased from Acros Chemicals, dichloromethane (99.5%) from Chemsolute, and poly(D,L-lactide-co-glycolide) (PLGA, Resomer® RG 502 H, M) w 7,000-17,000), Poly(3-hydroxybutyric acid) (PHB), average M n10,000), polyvinyl alcohol (PVA, Mowiol 4-88), (+)-α-pinene (>99%), (-)-β-pinene (99%), and (1S)-(-)-verbenone (94%) from Sigma Aldrich. Dulbecco's PBS 1x (phosphate buffer, containing 137 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO 4i and 1.8 mM KH2PO4) was manufactured by Capricorn Scientific. For HPLC analysis, HPLC-grade acetonitrile and water from VWR International were used, as well as HPLC-grade phosphoric acid from Merck and HPLC-grade dimethyl sulfoxide from Thermo Scientific. Olive oil (Ph. Eur., native) from Roth was used.

[0107] Carrying out measurements

[0108] Dynamic light scattering (DLS) and electrophoretic light scattering (ELS) were used to determine particle size and zeta potential using a Zetasizer Ultra from Malvern Panalytical at 25 °C and a 30 s equilibration time. The Zetasizer operates with a laser wavelength of 633 nm. DLS was measured in polystyrene microcuvettes (Brand) at 25 °C and a backscatter angle of 174.7° (particles before purification: 100 pL undiluted in a ZEN0040 cuvette; particles after purification: 10 pL particle suspension in 990 pL Milli-Q water or PBS 1x in a DTS0012 cuvette). In addition, DTS1070 capillary cuvettes (Malvern Panalytical) were used for ELS studies, with 10 pL of the particle suspension diluted 1x with 990 pL of Milli-Q or PBS. DSC / TGA and STA measurements were performed on a 449 F1 Jupiter® (Netzsch). Mass spectrometry was performed on a QMS 403 D Aeolos® from Netzsch. FTIR measurements were performed on a TENSOR 27 (Bruker).The IKA T10 basic from Ultra Turrax was used for the formulations. The Sonorex ultrasonic bath from Bandelin was used for resuspension.

[0109] A Sigma VP field emission scanning electron microscope (Carl Zeiss) was used to visualize the nanoparticles. The microscopy images were acquired with the InLens detector at accelerating voltages ranging from 3 kV to 8 kV. For this purpose, 10 pL of a 1 mg / mL suspension were applied to mica and dried for 1 h.

[0110] Carrying out the HPLC analysis

[0111] Cargo quantification was performed using a Thermo Scientific Dionex Ultimate 3000 HPLC. The following column was used: Chromolith® HighResolution RP-18 endcapped, LC Column 100 x 4.6 mm, macropore size: 1.5 pM, mesopore size: 15 nm.

[0112] Solid phase extraction (SPE) was performed for sample preparation. The SPE cartridge (Strata C18-E, surface area (m 2 / g): 500, pore size: 70, particle size: 55) is first rinsed with 1 mL methanol and then equilibrated with 2 mL water. 100 pL (α-pinene and β-pinene) or 50 pL (verbenone) of the suspensions are dissolved in 500 pL DMSO. 500 pL of the sample is eluted through the SPE cartridge into an HPLC vial. 1 mL of the stock solution is eluted through the SPE cartridge into the same HPLC vial, and the cargo (verbenone) is quantified according to the method. In the case of α-pinene and β-pinene, this first 1.5 mL aliquot is discarded. 3.5 mL of the stock solution is then eluted through the cartridge and collected in a single vial. 1.5 mL of this aliquot is transferred to an HPLC vial, and the cargo is quantified according to the method. Calibration is performed by preparing 0.3 mg / mL solutions of the cargoes from the corresponding stock solutions in a 10 mL volumetric flask.1:2 multiple dilutions are prepared from 0.6 pg / mL to 19 pg / mL.

[0113] Stock solution for α-pinene and β-pinene: 1:1 DMSO: (70% CH3CN, 30% H2O, 0.1% H3PO4)

[0114] Stock solution for verbenone: 1:1 DMSO: (30% CH3CN, 70% H2O, 0.1% H3PO4) Elution conditions for α-pinene and β-pinene: 70% CH3CN, 30% H2O H3PO4 0.1%, 10 min

[0115] Elution conditions for verbenone: 30% CH3CN, 70% H2O H3PO40.1%, 10 min. Eluents: CH3CN, H2O and H3PO40.1%

[0116] Autosampler: 20 °C, sample injection volume: 20 pL, injection volume blank: 40 ML

[0117] Oven temperature: 40 °C

[0118] Elution conditions: Isocratic

[0119] Detector: Diode array detector (DAD), Dionex UltiMate 3000 General formulation protocols

[0120] In a typical formulation, PLGA or PHB is used as the polymer. Typical solvents are ethyl acetate, dichloromethane, chloroform, acetone, dihydrolevoglucosenone (Cyrene), olive oil, sunflower oil, and / or rapeseed oil. The capsules are purified by centrifugation or dialysis. The messenger substances (cargo) are dissolved with the polymer or stock solutions with a concentration of 37 mg / mL each of α-pinene, β-pinene, or verbenone (hereinafter referred to as cargo) in olive oil are used.

[0121] Protocol for the production of PLGA capsules by emulsion:

[0122] 20 mg of PLGA are weighed into a 15 mL Falcon and dissolved in 945 pL of ethyl acetate. 55 pL of the cargo stock solution is added and dissolved, followed by 3% water (Milli-Q). A 2% PVA solution saturated with 8.3% ethyl acetate is prepared. The PVA solution (5 mL) is poured into the organic phase via the Falcon wall, ensuring that the phases are still clearly separated. The Ultra-Turrax is set to speed 6 (30,000 rpm) for 5 minutes to emulsify the solution. The resulting emulsion is quickly poured into 24 mL of water (the volume corresponds to 4 times the emulsion). The solvent is evaporated overnight at 800 rpm in an open vessel at room temperature. An undiluted sample is then measured by DLS. The suspension is purified to separate non-encapsulated cargo by centrifugation at 11,000 rpm for 60 min at 20 °C.The supernatant is decanted, and the pellet is resuspended in 2 mL of water (Milli-Q), ultrasonicated for 30 min, and left to stand overnight at 4 °C. Finally, particle size and distribution, as well as zeta potential, are determined in water (Milli-Q) and PBS buffer (1x). Aliquots are freeze-dried to determine the concentration of the final suspension and for cargo quantification by HPLC. Protocol for the preparation of PLGA capsules by inverse nanoprecipitation:

[0123] 20 mg of PLGA are weighed into a 15 mL flask and dissolved in 945 pL of acetone. 55 pL of the cargo stock solution are added and dissolved. The solution is transferred to a 10 mL tube and stirred at 800 rpm. 8 mL of a 2% PVA solution are filled into a syringe. The aqueous phase is injected into the organic phase using a syringe pump at a rate of 2 mL / min. The solvent is evaporated for 2 hours with stirring (800 rpm) at room temperature. An undiluted sample is then analyzed by DLS. The suspension is purified to remove non-encapsulated cargo by centrifugation (5804 R from Eppendorf) at 11,000 rpm for 60 min at 20 °C. The supernatant is poured off and the pellet is resuspended in 2 mL water (Milli-Q), treated in an ultrasonic bath for 30 min and left overnight at 4 °C.Finally, particle size and distribution, as well as zeta potential, are determined in water (Milli-Q) and PBS buffer (1x). Aliquots are freeze-dried to determine the concentration of the final suspension and for cargo quantification by HPLC.

[0124] Protocol for the production of PLGA capsules by nanoprecipitation:

[0125] 20 mg of PLGA are weighed into a 15 mL flask and dissolved in 945 pL of acetone. 55 pL of the cargo stock solution is added and dissolved. The solution is transferred into a syringe. 8 mL of a 2% PVA solution is stirred at 800 rpm in a 10 mL vial. The organic phase is injected into the organic phase using a syringe pump at a rate of 2 mL / min. The solvent is evaporated for 2 hours with stirring (800 rpm) at room temperature. An undiluted sample is then analyzed by DLS. The suspension is purified to remove non-encapsulated cargo by centrifugation at 11,000 rpm for 60 min at 20 °C. The supernatant is decanted, and the pellet is resuspended in 2 mL of water (Milli-Q) in xx, sonicated for 30 min, and left overnight at 4 °C. Finally, particle size and distribution, as well as zeta potential, are determined in water (Milli-Q) and PBS buffer (1x).Aliquots are freeze-dried to determine the concentration of the final suspension and for cargo quantification by HPLC.

[0126] Protocol for the production of PHB capsules by emulsion:

[0127] 20 mg of PLGA are weighed into a 15 mL Falcon and dissolved in 945 pL of dichloromethane. 55 pL of the cargo stock solution is added and dissolved, followed by 3% water (Milli-Q). A 2% PVA solution saturated with 8.3% dichloromethane is prepared. The PVA solution (5 mL) is poured into the organic phase via the Falcon wall, ensuring that the phases are still clearly separated. The Ultra-Turrax is set to speed 6 (30,000 rpm) for 5 minutes to emulsify the solution. The resulting emulsion is quickly poured into 24 mL of water (the volume corresponds to 4 times the emulsion). The solvent is evaporated overnight at 800 rpm in an open vessel at room temperature. An undiluted sample is then measured by DLS. The suspension is purified to remove non-encapsulated cargo by centrifugation at 11,000 rpm for 60 min at 20 °C.The supernatant is decanted, and the pellet is resuspended in 2 mL of water (Milli-Q), ultrasonicated for 30 min, and left to stand overnight at 4 °C. Finally, particle size and distribution, as well as zeta potential, are determined in water (Milli-Q) and PBS buffer (1x). Aliquots are freeze-dried to determine the concentration of the final suspension and for cargo quantification by HPLC.

[0128] Table 1: Overview of manufacturing methods, resulting particle size distribution (PDI: polydispersity index) and the zeta potential of the capsules, which was determined by DLS in water, as well as the loading of the capsules determined via HPLC. Figure 1 shows a scanning electron micrograph of a-pinene-loaded PLGA capsules prepared using emulsion.

[0129] Figure 2 shows a scanning electron micrograph of a-pinene-loaded PHB capsules prepared using emulsion.

[0130] Figure 3 shows a scanning electron micrograph of PLGA capsules loaded with cc-pinene, which were prepared by inverse nanoprecipitation. Figure 4 shows a scanning electron micrograph of PLGA capsules loaded with α-pinene, which were prepared by inverse nanoprecipitation.

[0131] Figure 5 shows the release of a-pinene detected via mass spectrometry in a STA.

[0132] Figure 6 shows a STA / TGA measurement of a-pinene loaded PHB capsules prepared via emulsion.

Claims

Patent claims 223fs02.wo 1. Dispersions containing water or biodegradable aprotic-polar solvents as dispersing agents and polymer particles or polymer-based nano- or microaggregates as dispersed phase, which are loaded with at least one messenger substance for attracting or repelling a predetermined wood-dwelling beetle species or for attracting a predator of this beetle species and optionally with further auxiliaries and additives, with the proviso that the polymer or the polymer-based nano- or microaggregate has at least one polymer-specific parameter selected from the group of glass transition temperature, crystallite melting temperature, supramolecular interactions, air humidity or targeted degradability, which changes within a predetermined temperature and / or humidity range so that the messenger substance contained in the particles is released,or that the polymer or the polymer-based nano- or microaggregate is degraded enzymatically or hydrolytically, so that the messenger substance contained in the particles is released.

2. Dispersions according to claim 1, characterized in that they are present as emulsions or as suspensions.

3. Dispersions according to claim 1, characterized in that they contain polymer particles or polymer-based nano- or microparticles selected from the group of polymer-based micelles, polymer-based vesicles, lipid-solid nanoparticles, lipid-polymer hybrid nanoparticles, polymer-based nanospheres or nanocapsules and polymer-based microspheres or microcapsules.

4. Dispersions according to at least one of claims 1 to 3, characterized in that they are used to attract wood-dwelling beetles which are beneficial or pests or to attract predators of the beetle pests or that they are used to drive away wood-dwelling beetle pests.

5. Dispersions according to at least one of claims 1 to 4, characterized in that they contain several messenger substances which attract wood-dwelling beetle pests and at the same time their predators, or that they contain, in addition to the messenger substances, further ingredients with which the beetle pests can be destroyed.

6. Dispersions according to at least one of claims 1 to 5, characterized in that they are used to influence the location of beetles living on, at or in trees or on or in the ground area of ​​trees.

7. Dispersions according to claim 6, characterized in that the beetles are weevils, preferably bark beetles, and particularly preferably spruce bark beetles (Ips typographus), copperplate engraver beetles (Pityogenes chalcographus), large and small wood bark beetles, oak bark beetles, striped timber bark beetles (Trypodendron lineatum) or black timber bark beetles (Xyleborus germanus).

8. Dispersions according to at least one of claims 1 to 7, characterized in that they contain nanoparticles or nanoaggregates with particle diameters (z-average) in the range of less than or equal to 1000 nm, preferably between 30 and 500 nm, particularly preferably between 40 and 250 nm and in particular between 50 and 200 nm.

9. Dispersions according to at least one of claims 1 to 7, characterized in that they contain microparticles or microaggregates with particle diameters (z-average) in the range of greater than or equal to 1 pm, preferably between 1 and 200 pm, and particularly preferably between 1 and 100 pm.

10. Dispersions according to at least one of claims 1 to 8, characterized in that they contain nanoparticles or nanoaggregates which have diameters (z-average) determined by DLS between 40 and 250 nm, preferably between 50 and 200 nm, and a polydispersity index of the particle diameters between 0.1 and 0.

3.

11. Dispersions according to at least one of claims 1 to 10, characterized in that the particles or aggregates of polymer are composed of biodegradable polymers or of bio-based polymers.

12. Dispersions according to at least one of claims 1 to 11, characterized in that the particles or aggregates are composed of polymers made of polyesters, polyamides or starches, in particular of polylactides, dextrans, alginates, starches, modified starches, polyhydroxyalkanoates or biodegradable polyesters or polyamides.

13. Dispersions according to at least one of claims 1 to 12, characterized in that the polymers have a specifically adjusted glass transition temperature.

14. Dispersions according to at least one of claims 1 to 12, characterized in that the polymers are biologically or hydrolytically degradable, in particular that the polymers are subject to enzymatic or hydrolytic degradation above a selected temperature.

15. Dispersions according to at least one of claims 1 to 14, characterized in that polymer blends are used whose polymeric components are held together by intermolecular bonds which dissolve at a predetermined temperature.

16. Dispersions according to at least one of claims 1 to 15, characterized in that they contain oils, in particular olive oil, sunflower oil or rapeseed oil.

17. Dispersions according to at least one of claims 1 to 16, characterized in that these dispersions contain, as disperse phase, nano- or microaggregates which, in addition to the polymer, have at least one oil and a messenger substance which acts as an attractant or repellent for beetles, in particular for bark beetles.

18. Films or aggregates / powders of polymer particles on tree bark, leaves and / or in the ground area of ​​trees, which have been produced by spraying the dispersions according to at least one of claims 1 to 17.

19. A method for influencing the location of wood-dwelling beetles by the use of messenger substances, the method comprising the following measures: i) introducing the dispersions according to claim 1, which contain messenger substances which attract the beetles and / or their predators or which drive the beetles away, the dispersions containing polymer particles which release the messenger substances above a predetermined temperature or which are degraded enzymatically or hydrolytically or by the action of light to release the messenger substances, and ii) applying the dispersions to a habitat in which the beetles are to be found or from which the beetles are to be kept away.

20. The method according to claim 19, characterized in that the dispersions are applied to the habitats by spraying, in particular manually or mechanically by means of spraying devices.

21. Method according to at least one of claims 19 or 20, characterized in that the messenger substances attract bark beetles and / or their predators or that the messenger substances drive away bark beetles 22. Use of the dispersions according to at least one of claims 1 to 16 for attracting wood-dwelling beetles and / or their predators into a habitat or for repelling wood-dwelling beetles from a habitat.

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