Orange peel extract for controlling fruit pests

Abstract

The invention relates to a method for producing an orange peel extract which is suitable for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), the method comprising the following steps: step a) subjecting orange peels to an extraction by placing the orange peels in an aqueous extraction solution containing at least 5 wt.% / vol.% NaCl, and preferably up to 15 wt.% / vol.% NaCl, for a predetermined period of time; and step b) separating the orange peel extract, which has been obtained by means of extraction, from the orange peels. The invention further relates to uses, methods, and trapping devices associated with controlling fruit flies, in particular spotted wing drosophila (Drosophila suzukii), in which the orange peel extract according to the invention is used.

Description

[0001] ORANGE PEEL EXTRACT FOR FRUIT PEST CONTROL

[0002] The invention relates to an orange peel extract that has been proven useful and effective in controlling fruit flies, in particular spotted wing drosophila (Drosophila suzukii), and to a method for producing the orange peel extract. The invention further relates to uses, methods, and trapping devices in connection with the control of fruit flies, in particular spotted wing drosophila (Drosophila suzukii), in which the orange peel extract according to the invention is used.

[0003] There are approximately 1,500 Drosophila species worldwide, commonly known as vinegar flies. One of the most problematic species is the spotted-wing drosophila (Drosophila suzukii), which has been introduced from Southeast Asia to many continents and is a pest of increasing concern for agriculture worldwide, including Europe. The ability of female flies to lay their eggs in fruits of varying ripeness, combined with the accelerated development of offspring in warmer climates and the absence of natural enemies, leads to rapid population growth. Through their toothed ovipositor, females lay their eggs in primarily red-colored fruits of almost all ripeness stages, such as grapes, raspberries, and cherries, where the larvae mature. As soon as the fly larvae hatch, the fruit begins to rot, which can destroy up to 80% of the harvest and therefore leads to significant financial losses.Physical damage to the fruit caused by the laying behavior of female flies and the hatching of their larvae also provides access to microbial infections that cause further fruit damage. This poses significant challenges to fruit production and viticulture, which are further exacerbated by the increasing prevalence of pesticide resistance.

[0004] Spotted-wing drosophila (Drosophila suzukii) particularly infest soft-shell fruit (raspberries, grapes, elderberries, etc.), allowing the larvae to mature within the fruit and destroy entire harvests. There is great interest in Austria, the EU, and worldwide in developing effective pesticides against spotted-wing drosophila that are environmentally friendly and sustainable, and harmless to humans even when treated fruit is consumed. Currently, fruit fly trap baits such as the liquid bait "Drosa Lure™" are approved for infestation monitoring, but these have no regulatory effect on the spotted-wing drosophila population.

[0005] Certain chemical pesticides (e.g. Azadirachtin®, Chlorpyrifos®, Cyazypyr®, Dimethoate, Imidacloprid, Lampda-Cyhalothrin, Spinosad and Malathion) have been shown to be effective against Drosophila suzukii. However, all of these pesticides can have negative consequences for a large group of non-target insect species, some of which are important pollinators. For example, the pesticide Spintor™ (active ingredient is the contact and ingestion toxin spinosad), which is currently approved for viticulture in the EU and widely used in various agricultural crops, is effective against spotted wing drosophila, but has a non-specific effect on non-target organisms, is harmful to bees and is only very slowly biodegradable. The toxin spinosad is obtained from the bacteria Saccharopolyspora spinosa. However, winegrowers must observe a waiting period of approximately 14 days in conventional viticulture and approximately 2 weeks in poplar.In organic viticulture, a minimum of 28 days should be observed between the last Spintor™ treatment and harvest. Due to the high reproduction rate of spotted wing drosophila, crop damage can be severe during this period. Pesticides such as "Karate Zeon" (active ingredient lambda-cyhalodrin) or "Piretro Verde" (active ingredient pyrethrin) are also approved for the control of spotted wing drosophila in conventional viticulture. These products are also questionable due to their slow biodegradation and non-specific effects.

[0006] Inorganic agents such as kaolin (hydrated aluminum silicate) are only moderately effective against spotted wing drosophila, discolor fruit, and are also problematic due to the high dust generation during application. Furthermore, spotted wing drosophila can develop resistance to these pesticides over time. A recent study reported that excessive use of spinosad can be problematic, as spinosad resistance emerged in a Drosophila suzukii population in California. Consequently, additional strategies for managing insecticide resistance are urgently needed to control this pest in the future [Gress and Zalom, 2019, Pest Manag Sci 75:1270-1276. http i.org / 10.1002 / ps.5240].

[0007] In recent years, trends toward sustainable control strategies have greatly increased research attention. Despite these efforts, only a few approved baits and insecticides against Drosophila suzukii are available in Europe and other continents, making more sustainable control measures urgently necessary. There is therefore a constant need for effective agents or insecticides for controlling fruit flies, in particular for controlling spotted wing drosophila, that are largely harmless to humans, the environment, and non-target organisms, sustainable, preferably based on the recycling of waste materials, and also cost-effective to produce. It is therefore an object of the invention to eliminate the disadvantages of the plant protection products known from the prior art and to meet this need.

[0008] This object is achieved in a first aspect according to the invention by a process for producing an orange peel extract which is suitable for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), the process comprising the following steps:

[0009] Step a) subjecting orange peels to extraction by placing the orange peels in an aqueous extraction solution containing at least 5 w / v% NaCl, and preferably up to 15 w / v% NaCl, for a predetermined period of time; and

[0010] Step b) Separating the orange peel extract obtained by extraction from the orange peels.

[0011] This object is achieved in a further aspect by an orange peel extract for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), which is produced by a process according to the invention and as described in this disclosure.

[0012] It was surprisingly found that an orange peel extract produced using the process according to the invention acts very rapidly and effectively against fruit flies, particularly spotted wing drosophila, within a short period of time. The experiments accompanying this disclosure (see experimental data in Examples 1, 2, and 3, as well as the accompanying figures) clearly demonstrate that the orange peel extract according to the invention attracts spotted wing drosophila and exerts an insecticidal effect on them. The accompanying experimental data show that spotted wing drosophila infestation on grapes can be significantly reduced thanks to the orange peel extract according to the invention, and a regulating effect on the spotted wing drosophila population can be achieved.

[0013] Further advantages of the orange peel extract described herein are: Due to its constituents and its biodegradability, the extract is largely harmless to humans, the environment, and non-target organisms. The orange peels used to produce the orange peel extract can be inexpensively obtained from biological waste, e.g., from orange juice production. The orange peel extract is therefore sustainable and, due to its constituents, cost-effective to produce. Furthermore, the production of the orange peel extract is based on a simple-to-implement process.

[0014] The orange peel extract of the invention can be used in combination with commercially available fruit fly traps adapted for liquid bait, which only allow fruit fly-sized insects to enter. This makes the application of the orange peel extract harmless to bees and other larger non-target organisms. Furthermore, it can be easily applied in the field without any laboratory equipment.

[0015] The orange peel extracts produced by the process according to the invention are used, preferably in combination with the traps described in this disclosure, particularly advantageously, but not limited to, in the following applications for the treatment of spotted wing drosophila infestation:

[0016] • Use as a biocide / plant protection product for organic farming (viticulture, fruit crops), for example in cooperation with farmers' cooperatives or state institutions (e.g. Chamber of Commerce, Federal Office for Food Safety).

[0017] • Use as a biocide / plant protection product for private households and gardens, e.g. in the form of ready-to-use fruit fly traps filled with orange peel extract (e.g. sold in hardware stores, drugstores, online shops, etc.).

[0018] • For monitoring plant crops to detect a possible spotted wing drosophila infestation as early as possible, or for data collection and research purposes related to spotted wing drosophila infestation. It goes without saying that the orange peel extract according to the invention is suitable as a plant protection agent for all plants that can be infested by fruit flies, especially spotted wing drosophila. The term "plant" used herein refers, for the purposes of this invention, to all plants that can be infested by fruit flies, especially spotted wing drosophila, including, but not limited to, fruit crops, vineyards, wild plants such as wild blueberries, fruit plants in private and public gardens, etc.The invention and the subject matter, methods and uses described herein are useful, among other things, for conventional agricultural production, organic agricultural production, private use (e.g. home gardens) and public spaces (e.g. public parks, gardens, public areas / roadsides planted with fruit plants).

[0019] As mentioned, the orange peels used in the process according to the invention advantageously come from biological waste, e.g., from orange juice production. For the extraction according to step a) of the process, the orange peels are placed in the extraction solution containing at least 5 wt. / vol.% NaCl. For example, the peels of approximately 3–5 oranges, depending on their size, can be placed in 500 ml of NaCl extraction solution for the extraction. Advantageously, approximately 150–500 g of orange peels are used per liter of NaCl extraction solution. It goes without saying that the orange peels can be crushed into small pieces before adding the extraction solution. For ecological and economic reasons, it is advantageous if the extraction solution contains no more than 15 wt. / vol.% NaCl.

[0020] The separation of the orange peel extract obtained by extraction from the orange peels according to step b) of the process can be carried out by common methods known to a person skilled in the art for separating extracts from a material to be extracted, for example by a pressing process through a fabric, net, cloth or sieve of appropriate mesh size, or by centrifugation.

[0021] A person skilled in the art will readily and without undue effort be able to carry out the process according to the invention based on the present disclosure and with the aid of simple routine experiments. Preferably, the extraction according to step a) of the process according to the invention is carried out over a period of at least 2 hours. Depending on the starting material (orange peels), it may, for example, be provided that the extraction according to step a) is carried out over a period of at least 2 hours, or at least 12 hours, or at least 24 hours. Normally, however, it will be sufficient to keep the extraction according to step a) short and to carry it out over a period of approximately 2 hours.

[0022] In an advantageous embodiment of the method according to the invention, in the separation process according to step b), the orange peels are removed from the aqueous extraction solution and then the removed orange peels are subjected to at least one pressing process in order to separate the orange peel extract from the removed orange peels.

[0023] In an advantageous development of this embodiment of the method, in the separation process according to step b), the orange peels removed from the aqueous extraction solution are subjected to a first pressing process and a second pressing process following the first pressing process, wherein: in the first pressing process, the removed orange peels are pressed by a first pressing device, whereby a pressed product comprising orange peel extract and orange peel parts is obtained, and in the second pressing process, the pressed product obtained in the first pressing process is pressed by a second pressing device, whereby the orange peel extract is separated from the orange peel parts.

[0024] In the first pressing process, the previously extracted orange peels are removed from the aqueous extraction solution, any excess extraction solution is removed, and pressed through a first pressing device (see the attached experiments, in which a garlic press or a kitchen slicer was used). This produces a pressed product comprising orange peel extract and orange peel fragments. A person skilled in the art will appreciate that the orange peels removed from the aqueous extraction solution can be crushed before the first pressing process or, depending on the first pressing device used, must be crushed into suitable pieces.It will also be clear to a person skilled in the art that, depending on the type of first pressing device used, part of the solid components of the orange peels may remain in the first pressing device after the first pressing process and the other part of the solid components may enter the pressed product (as is the case in a garlic press), whereby the proportion of the remaining solid components and the solid components contained in the pressed product may vary depending on the first pressing device used.

[0025] In the subsequent second pressing process, the orange peel extract is pressed from the solid components contained in the pressed product, i.e. the orange peel parts, using the second pressing device and collected in a suitable container; this is done, for example, by pressing the pressed product through a fabric, net, cloth, or sieve of appropriate mesh size.

[0026] A skilled person will be aware that the first and / or second pressing operation may be repeated if necessary in the procedure.

[0027] Preferably, the aqueous extraction solution contains 5 - 15 w / v% NaCl, more preferably 8 - 12 w / v% NaCl.

[0028] In a particularly preferred embodiment, in which a pronounced attractant and insecticidal effect against spotted wing drosophila has been observed, while at the same time the requirement for the chemical NaCl can be kept low, the aqueous extraction solution contains approximately 10 wt / vol% NaCl. "Approximately" refers to a deviation of up to + / - 0.5 wt / vol% NaCl from the specified NaCl concentration.

[0029] In a further development of the process according to the invention, the aqueous extraction solution additionally contains 5-10 vol. / vol.% ethanol for preservation purposes. As can be seen from the enclosed experimental data, an orange peel extract in which the orange peels were extracted in an extraction solution containing 10 wt. / vol.% NaCl and 10 vol. / vol.% ethanol showed a slightly higher insecticidal effect compared to an orange peel extract in which the orange peels were extracted in an extraction solution containing 10 wt. / vol.% NaCl. To increase the attractant effect of the orange peel extract, it can be advantageous if the process comprises a step c) following step b), in which 1-10 vol. / vol.% vinegar, e.g. 1-5 vol. / vol.% vinegar, and / or 1-5 vol. / vol.% red wine are added to the orange peel extract obtained in step b).

[0030] A further object of the invention relates to an alternative, but less preferred, process variant for producing an orange peel extract suitable for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), said process variant comprising the following steps: step aa) subjecting orange peels to an extraction by soaking the orange peels in water for a predetermined period of time; step bb) separating an aqueous extract obtained in step aa) by means of the extraction from the orange peels; and step cc) adding NaCl to the aqueous extract separated in step bb), in a concentration of at least 5 w / v% NaCl, and preferably up to 15 w / v% NaCl. This process represents a modification of the previously described process (cf. independent claim 1). With this modified process (cf.Independent claim 9; extraction in water; subsequent addition of NaCl) also produces an orange peel extract with an attractant and killing effect, the effect of which, however, has proven in comparative tests to be less effective than the effect of the orange peel extract obtained using the method described above (extraction in an NaCl-containing extraction solution); see selective test under Example 1 / Point 1.4 / Fig. 3. The extraction according to step aa) is preferably carried out over a period of at least 2 hours. Depending on the starting material (orange peel), it can, for example, be provided that the extraction according to step aa) is carried out over a period of at least 2 hours, or at least 12 hours, or at least 24 hours. Normally, however, it will be sufficient to keep the extraction according to step aa) short and to carry it out over a period of approximately 2 hours.Preferably, in the separation process according to step bb), the orange peels are removed from the water and then the removed orange peels are subjected to at least one pressing process in order to separate the aqueous extract from the removed orange peels. The separation process preferably takes place in a first and second pressing process, wherein in the first pressing process, the removed orange peels are pressed through a first pressing device, whereby a pressed product comprising the aqueous extract and orange peel parts is obtained, and in the second pressing process, the pressed product obtained in the first pressing process is pressed through a second pressing device, whereby the aqueous extract is separated from the orange peel parts; regarding the details of the pressing processes, see the description above for the other process, which are also applicable mutatis mutandis to this process variant. Preferably, in step cc), 5 - 15 wt. / vol.% NaCl, preferably 8 - 12 w / v% NaCl, is added to obtain the orange peel extract. Particularly preferably, approximately 10 w / v% NaCl is added in step cc). In a further development of this process variant, in order to increase the attractant effect or the insecticidal effect, the process can also comprise a step dd) following step cc) or a step dd) taking place simultaneously with step cc), wherein in step dd) 1-10 vol / vol% vinegar, e.g. 1 - 5 vol / vol% vinegar, and / or 1-5 vol / vol% red wine and / or 5-10 vol / vol% EtOH are added to the orange peel extract obtained in step cc). Vinegar, ethanol and red wine increase the attractant effect, and the addition of ethanol additionally increases the insecticidal and preservative effect.

[0031] The invention further relates to an insecticide for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), containing or consisting of an orange peel extract produced by a process according to the invention and as described in this disclosure. The insecticide according to the invention contains the orange peel extract according to the invention as the insecticidally active ingredient, preferably as the sole insecticidally active ingredient. The insecticide may contain further additives that do not impair the effect of the orange peel extract, such as preservatives (e.g., ethanol, benzoic acid, citric acid) to increase storage stability, liquid attractants or baits for fruit flies, fragrances, etc., whereby, in accordance with the fundamental inventive concept, these additives are advantageously largely harmless to humans and the environment, biodegradable, sustainable, and economical. A person skilled in this field is familiar with such additives and, based on their specialist knowledge and simple routine tests, is readily able to select suitable additives and add them in the appropriate amount to the orange peel extract according to the invention.

[0032] In a further embodiment, the insecticide may contain, as an additional component, a carrier material onto which the orange peel extract is applied or embedded. The carrier material is preferably a semi-liquid carrier material, such as, in particular, hydrogel or agarose, onto which the orange peel extract is dripped or added to the carrier material. This embodiment can be realized, for example, in the form of flat, open containers into which the carrier material with the orange peel extract is filled and which can be interchangeably placed in a fruit fly trap; in this example, this embodiment is therefore used as an interchangeable replacement container in combination with a fruit fly trap.

[0033] Another object of the invention relates to a trap for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), comprising:

[0034] • a closed housing with at least one opening and a

[0035] Interior area, wherein the at least one passage opening is designed and dimensioned so that fruit flies, in particular spotted wing drosophila (Drosophila suzukii), can pass from the outside through the at least one passage opening into the interior area of ​​the closed housing, whereas larger non-target organisms cannot pass through the at least one passage opening, and

[0036] • a predetermined amount of an orange peel extract according to the invention as disclosed herein or an insecticide according to the invention as disclosed herein arranged in the interior of the closed housing.

[0037] The "predetermined amount" of orange peel extract is selected to ensure effective attraction and killing of fruit flies, especially spotted wing drosophila. The predetermined amount can depend on various factors such as the size of the trap, the severity of the infestation, the location of the infestation, the size of the infested plant, the ambient temperature, etc. A person skilled in the art is readily able to determine the predetermined amount of orange peel extract based on the present disclosure, their specialist knowledge, and simple routine tests, and to adapt it to the respective requirements or situation. In an advantageous embodiment of the trap according to the invention for attracting and killing fruit flies, the predetermined amount of orange peel extract is applied to or embedded in a carrier material to prevent the orange peel extract or the insecticide from drying out too quickly.The carrier material is preferably a semi-liquid carrier material such as in particular hydrogel (herein also referred to as water gel) or agarose, preferably hydrogel, onto which the orange peel extract is dropped or added to the carrier material.

[0038] It may also be necessary to moisten the carrier material with orange peel extract at regular intervals, e.g., once a week (e.g., by dripping orange peel extract onto the carrier material) to prevent a decline in the attractant and insecticidal effect. Replacing the carrier material in the trap would thus be unnecessary.

[0039] To create the trap according to the invention, any type of fruit fly trap that meets the above requirements with regard to passageways for fruit flies can be used as the closed housing. The traps are advantageously at least partially colored red, for example, they have at least one red cover to further increase the attractant effect on fruit flies. For example, at least parts of the trap housing are made of a red-colored material (e.g., red-colored plastic), or the housing is at least partially painted red or provided with a red-colored coating. The orange peel extract is placed in the trap either in liquid form or in combination with the described carrier material, where it exerts its attractant and insecticidal effect on fruit flies, particularly spotted wing drosophila.The trap may also have additional small openings or pores in the housing, in a manner known per se, through which fruit flies cannot enter the trap, but through which volatile compounds of the orange peel extract can escape from the housing to the outside in order to attract the fruit flies.

[0040] Fig. 8 shows a simplified schematic representation of a trap 1 according to the invention, wherein the design of the trap 1 shown in Fig. 8 is merely exemplary and not restrictive. It will be clear to a person skilled in the art that any type of fruit fly trap that meets the aforementioned requirements regarding fruit fly passage openings can be used to implement a trap according to the invention as a closed housing.

[0041] The exemplary trap 1 shown in Fig. 8 comprises a closed housing 2, which in this example is composed of a round container 2a and a matching round lid 2b in the manner of a raised Petri dish. However, a person skilled in the art will appreciate that the container 2a and the lid 2b of the trap 1 may be shaped other than round and may, for example, be square or octagonal. The container 2a and the lid 2b define an interior region 4 of the closed housing 2. The container 2a and the lid 2b are preferably detachably connected to one another, for example by means of a twist, snap, or bayonet closure.The container 2a is provided with passage openings 3, wherein the passage openings 3 are designed and dimensioned such that fruit flies, in particular spotted wing drosophila (Drosophila suzukii), can pass from the outside through the passage openings 3 into the interior 4 of the closed housing 2, whereas larger non-target organisms cannot pass through the passage openings 3. In the interior 4 of the closed housing 2 there is a predetermined amount of an orange peel extract 5 according to the invention and a semi-liquid carrier material 6, in this specific case a hydrogel 6. In this example, the orange peel extract 5 was dripped onto the carrier material 6. The lid 2b of the trap 1 is made of a red-colored plastic material to further increase the attraction to the fruit flies. The housing 2 of the trap 1 preferably comprises a suspension device, e.g.in the form of a loop, hook or clip arranged on the cover 2b in order to attach the trap to its place of use, e.g. to a branch of a fruit tree or vine.

[0042] In a further aspect, the present invention relates to the use of an orange peel extract produced by the process according to the invention as an insecticide.

[0043] In a further aspect, the present invention relates to the use of an orange peel extract produced by the process according to the invention as an agent for attracting and killing fruit flies. In particular, the invention relates to the use of the orange peel extract according to the invention as an insecticide against spotted wing drosophila (Drosophila suzukii) or as an agent for attracting and killing spotted wing drosophila (Drosophila suzukii).

[0044] The orange peel extract produced by the process according to the invention is advantageously used in undiluted form.

[0045] In order to prevent the orange peel extract from drying out too quickly, it is advantageous, as already described in detail above, if the orange peel extract is applied to a carrier material or embedded in it.

[0046] The invention is preferably used by means of a trap according to the invention for attracting and killing fruit flies as disclosed and described herein.

[0047] In a further aspect, the present invention relates to a method for attracting and killing fruit flies, in particular for attracting and killing spotted wing drosophila (Drosophila suzukii), wherein one or more of the traps according to the invention and disclosed herein are arranged at locations located within or near plants infested with fruit flies, in particular plants infested with spotted wing drosophila (Drosophila suzukii), or located within or near plants threatened by fruit fly infestation, in particular by spotted wing drosophila (Drosophila suzukii). Regarding the term "plants" and suitable application locations, see the detailed explanations above.

[0048] The orange peel extract produced by the process according to the invention is advantageously used in the process for attracting and killing fruit flies, in particular for attracting and killing spotted wing drosophila (Drosophila suzukii), in undiluted form.

[0049] The invention and its advantages are explained in more detail in the accompanying experimental data and examples, but are not limited thereto. Examples, tests, and experimental data

[0050] The experiments and experimental data presented below in the examples and attached figures impressively demonstrate that the orange peel extract developed at the University of Graz acts very quickly and effectively against spotted wing drosophila within a short period of time. The orange peel extract attracts spotted wing drosophila and exerts an insecticidal effect on them. Among other things, various selection experiments were conducted with Drosophila suzukii in large terrariums, demonstrating that the orange peel extract according to the invention successfully attracts and kills spotted wing drosophila, thus keeping them away from grapes.

[0051] The figures show the following:

[0052] Fig. 1A and Fig. 1B show the results of a choice experiment in which the orange peel extract according to the invention was applied to water gel and compared with water gel without orange peel extract. The graph in Fig. 1A shows the number of flies per 10 grapes, and the graph in Fig. 1B shows the number of dead spotted wing drosophila.

[0053] Fig. 2A, Fig. 2B, and Fig. 2C show the insecticidal effect of different formulations of the orange peel extract according to the invention on spotted wing drosophila; diagram in Fig. 2A: comparison of formulations with and without 10% EtOH; diagram in Fig. 2B: comparison of differently diluted orange peel extracts (undiluted, 1:2 diluted, 1:5 diluted); diagram in Fig. 2C: comparison of different NaCl concentrations in the orange peel extract (10% NaCl, 5% NaCl, 1% NaCl).

[0054] Fig. 3 shows the result of a comparative experiment in which the insecticidal activity of orange peel extracts prepared using different preparation methods (addition of NaCl before the extraction step; addition of NaCl after the extraction step) was compared.

[0055] Fig. 4A and Fig. 4B show the results of a choice experiment comparing the orange peel extract according to the invention on water gel and water gel without orange peel extract. Fig. 4A shows a photo of the Petri dish filled with water gel, and Fig. 4B shows a photo of the Petri dish filled with water gel and orange peel extract (the killed D. suzukii flies are marked by circles).

[0056] Fig. 5A and Fig. 5B show the results of 10 repetitions of a choice experiment comparing the orange peel extract on water gel according to the invention and water gel without orange peel extract. The graph in Fig. 5A shows the number of dead spotted wing drosophila, and the graph in Fig. 5B shows the mean number of dead spotted wing drosophila over the course of the experiment (after 24 hours, 48 ​​hours, 72 hours, and 96 hours).

[0057] Figure 6 shows the results of a choice experiment comparing the orange peel extract on water gel according to the invention and water gel without orange peel extract. The number of larvae per 10 grapes suspended above the two Petri dishes is shown.

[0058] Fig. 7 shows the results of a random experiment in which the effect of a freshly prepared orange peel extract according to the invention was compared with the effect of a 3-day-old and a 6-day-old orange peel extract according to the invention. The graph in Fig. 7 shows the number of dead spotted wing drosophila as a function of the orange peel extract used (fresh, 3-day-old, 6-day-old).

[0059] Fig. 8 shows a simplified schematic representation of a fruit fly trap according to the invention.

[0060] Fig. 9 shows the result of a field trial in which the effect of an orange juice extract according to the invention was tested in the field and compared with the effect of DrosaLure™, a commercially available attractant.

[0061] EXAMPLE 1 - First series of experiments

[0062] 1.1. Production of orange peel extracts according to the invention

[0063] Orange Peel Extract OE-NaCl110: The previous day, orange peels were soaked in an aqueous 10 w / v% NaCl extraction solution. The next day, the orange peels were removed from the NaCl extraction solution and, after removing excess NaCl extraction solution, pressed through a garlic press in a first pressing step. The juice obtained in the first pressing step was then pressed through a fine mesh into a container in a second pressing step to remove any remaining orange peel particles. The resulting liquid is an orange peel extract (OE-NaCl110) according to the invention.

[0064] Orange peel extract OE-NaClO-EtOHlO: In a further formulation according to the invention, the orange peels were placed in a 10 wt. / vol.% NaCl solution, which additionally contained 10 vol. / vol.% ethanol, and prepared analogously according to the manufacturing process described above.

[0065] Orange peel extract OE-NaC110-vinegar-red wine: In a further formulation of the orange peel extract according to the invention (prepared with a 10 wt. / vol.% NaCl extraction solution according to the above protocol), 3% vinegar and 3% red wine were additionally added to the orange peel extract to increase the attractant effect.

[0066] In further formulations of the orange peel extract according to the invention, instead of an aqueous 10 w / v% NaCl extraction solution, aqueous NaCl extraction solutions with 5 w / v% (orange peel extract OE-NaC15) or 1 w / v% NaCl (orange peel extract OE-NaC11) were prepared analogously to the preparation process described above.

[0067] Orange peel extract OE-NaC110post: In a further formulation of the orange peel extract according to the invention, the orange peels were soaked overnight in water only (without salt). The aqueous extract was obtained by pressing as described above, and NaCl was added to the resulting aqueous extract only after the extraction process (= orange peel extract OE-NaC110post). The extraction and pressing process was carried out analogously as described above. The electrical conductivity of the resulting aqueous extract (without NaCl) was then compared with the orange peel extract OE-NaClO. As expected, the aqueous extract without NaCl showed a lower conductivity and thus a higher electrical resistance.NaCl was then added to the aqueous extract obtained from the orange peels without NaCl until the conductivities and thus the salt concentrations of the orange peel extract OE-NaCl110post and the orange peel extract OE-NaCl10 corresponded to each other. Control extract: An orange peel extract prepared with only water and without the addition of NaCl according to the above extraction and pressing steps was used as a non-inventive control.

[0068] 1.2 Choice test: Effect of the orange peel extract according to the invention in choice tests

[0069] Fruit flies D. suzukii (swimmer drosophila) were placed in a large terrarium. A Petri dish (15 cm diameter) and a bunch of grapes containing 10 grapes were placed on opposite sides of the terrarium. A layer of water gel was spread on the bottom of the Petri dishes. 15 ml of the inventive orange peel extract (OE) - (OE-NaCl110; see section 1.1) was then added to one of the Petri dishes, and 15 ml of water was added to the other Petri dish. After 6 days, the larvae in the respective grapes (placed in 10% NaCl solution) were counted. There were 9 larvae in the grapes above the water gel, whereas only 2 larvae were added to the grapes above the orange peel extract.

[0070] The results of the choice experiment are shown in the graphs in Fig. 1A and Fig. 1B. The graph in Fig. 1A shows the number of larvae per 10 grapes in comparison of grapes over the orange peel extract with water gel and grapes over the water gel (control); the graph in Fig. 1B shows the number of dead spotted wing drosophila in the Petri dishes with the water gel with and without the orange peel extract.

[0071] The results of this trial show that the orange peel extract attracted the spotted wing drosophila, thereby reducing the infestation on the grapes. Fifty-one dead flies were counted in the Petri dish containing the orange peel extract, while no dead flies were present in the water gel.

[0072] 1.3 Choice test: Effect of different formulations of the orange peel extract according to the invention

[0073] In this trial, different formulations of the orange peel extract (OE) according to the invention were tested for their insecticidal activity against spotted wing drosophila (D. suzukii). The diagrams in Fig. 2A, Fig. 2B, and Fig. 2C show the insecticidal activity of different formulations of the orange peel extract according to the invention on spotted wing drosophila.

[0074] The comparison of the efficacy of formulations with and without 10% EtOH is shown in the diagram in Fig. 2A (for preparation of the formulations, see section 1.1). Control extract = "orange peels in water"; OE-NaClO = "orange peels in 10% NaCl"; OE-NaClO-EtOHO = "orange peels in 10% NaCl + 10% EtOH." The efficacy of the orange peel extract, whose peels were soaked in a 10 w / v% NaCl + 10 v / v% EtOH solution, showed only a slightly higher insecticidal activity compared to the extract whose peels were soaked only in a 10 w / v% NaCl solution.

[0075] The comparison of the effects of different diluted formulations, namely OE-NaClO undiluted, OE-NaClO diluted 1:2 with water, and OE-NaCl diluted 1:5 with water, is shown in the diagram in Fig. 2B. In these choice experiments, a significant decrease in the number of dead flies was observed five days after the start of the experiment (Fig. 2B).

[0076] The graph in Fig. 2C shows the comparison of the effect at different NaCl concentrations in the orange peel extract (OE-NaClO ("10% NaCl"); OE-NaClS ("5% NaCl"), OE-NaClI ("1% NaCl")). Likewise, a decrease in the number of dead flies was observed in those formulations in which the NaCl concentration was lower (5% NaCl, 1% NaCl; Fig. 2C). The highest number of dead D. suzu / cü flies was observed with OE-NaClO (extraction with a 10% saline solution), while the lowest number of dead flies was recorded with OE-NaClI (extraction with a 1% saline solution).

[0077] 1.4 Investigation of the effect of orange peel extracts when NaCl was added before and after the extraction process

[0078] To investigate the effectiveness of orange peel extract against spotted wing drosophila when NaCl was added before or after the extraction process, selective trials were conducted with spotted wing drosophila. The insecticidal effects of the orange peel extracts OE-NaClO and OE-NaClOpost (for preparation, see section 1.1) on spotted wing drosophila were investigated.

[0079] 15 ml of the two extracts OE-NaClO and OE-NaClO post were added dropwise to two Petri dishes filled with water gel. The spotted wing drosophila was allowed to freely choose between the two prepared Petri dishes and a small dish of sugar solution (as a control) in a large terrarium. After 4 days, it was observed that more dead flies were present on the Petri dish containing the OE-NaClO extract than in the dish containing the OE-NaClO post extract (see Fig. 3). This result demonstrates that adding salt prior to the extraction process, i.e., using a NaCl-containing extraction solution, increases the attractant and insecticidal effect compared to an extract where the salt was added subsequently. Overall, more than 90% of the spotted wing drosophila died in this experiment.

[0080] EXAMPLE 2 - Second series of experiments

[0081] 2.1 Materials and methods

[0082] 2.1.1 Insect breeding.

[0083] The D. suzukii individuals used in this study were reared in small, foam-sealed plastic bottles (Carolina® Biological Supply Company, Burlington, North Carolina, USA) at the Institute of Zoology in Graz, Austria. Instant Drosophila Medium (Carolina® Biological Supply Company, Burlington, North Carolina, USA) was mixed with tap water and dried yeast (Carolina Dried Yeast C19010) to feed the flies. Individuals were provided with fresh food every 3 days. The light-dark cycle was 12:12 h, and the average room temperature was 25.5 ± 1 °C (mean ± SD). The relative humidity ranged from 45–50%.

[0084] 2.1.2 Production of the orange peel extract according to the invention

[0085] Orange Peel Extract OE-NaClO': Organic oranges grown in southern Italy were purchased and their peels removed for the production of the orange peel extracts according to the invention. First, the peels were cut into small pieces and immersed in an aqueous solution containing 10 w / v% NaCl for two hours. The excess of this solution was then removed using a kitchen towel, and the orange peels were shredded using a kitchen slicer. The resulting mass was placed in a fine-mesh nylon net to manually squeeze out the orange peels. The resulting liquid is an orange peel extract (OE-NaClO') according to the invention.For the experiments in this series, 10 to 15 ml of the resulting orange peel extract OE-NaCl110' was poured onto a Petri dish (13 cm in diameter) containing 90 ml of water gel (also called hydrogel), which was prepared by adding 90 ml of water to 1.05 g of Terrabest Aqua-Water granules (Feeders & more GmbH, Germany). The water gel delays the drying of the orange peel extract and promotes the release of volatile substances attractive to fruit flies. The Petri dishes were used either fresh or 3 to 6 days later in two-choice experiments. In the meantime, the orange peel extract was stored at room temperature.

[0086] 2.1.3 Conducting the election experiments and counting the larvae.

[0087] 40 D. suzu / cn-ln ivi uen (spotted cherry vinegar flies) of both sexes were released into a terrarium equidistant from two Petri dishes. They were given the choice between grape berries and two Petri dishes containing either OE-NaCl110' on water gel or just the water gel (control). Two bunches of grapes, each containing 10 grape berries, were placed next to each other in the terrarium at a distance of 75 centimeters. The distance between the grape berries and the Petri dishes below was 60 cm, and the distance between the two Petri dishes was 70 cm. During the experiments, the number of dead flies found in both Petri dishes was counted daily, and the number of fly larvae in the grape berries was counted after 4 days. Grapes from organic red wine grapes (Frutura Obst & Gemüse Kompetenzzentrum GmbH, Hartl b.Kaindorf, Austria) were used as target fruits for the choice trials after the grapes were carefully washed with tap water before each trial. The Petri dishes were covered with a red lid of the same color (diameter 22 cm, height 4 cm) with four large holes on the side (10 cm x 2 cm) to prevent the flies from choosing between the Petri dishes based on color. All choice trials were conducted in a glass terrarium subjected to a 14:10 h light / dark cycle (Juwel Aquarium LED Natural 6500 K plus LED Day 9000 K 11-watt). During the choice trials, the temperature was 25.5 ± 1 °C (mean ± SD) and the relative humidity was 42 ± 11% (mean ± SD). At the end of the choice trials, the grapes were cut into pieces and immersed in 250 mL of aqueous salt solution (10 wt / vol% NaCl) to facilitate larval counting. This saltwater treatment caused the larvae to float on the water surface.All statistical tests were performed in R Studio (version 23.12.1, Posit Software, PBC).

[0088] 2.2 Results

[0089] In the choice experiments conducted in this study, 40 D. suzukii individuals were presented with two red wine grapes (each grape containing 10 grapes) in a terrarium. One grape was placed over a Petri dish containing water gel with the orange peel extract OE-NaClO' according to the invention, while the other grape was placed over a Petri dish containing only water gel (control). To ensure unbiased choice based on odor impressions, both Petri dishes were permanently covered with red lids of the same color and large holes on the side to allow access to the Petri dish. After a period of four days, the number of dead D. suzukii flies was significantly higher on the OE-NaClO' orange peel extract side than on the hydrogel control side, as shown in Fig. 4A and Fig. 4B. Fig. 4A shows a photo of the Petri dish filled with water gel and Fig.4B shows a photograph of the Petri dish filled with water gel and orange peel extract (the killed D. suzukü flies are marked by circles).

[0090] In ten selection trials conducted, a significantly higher average number of dead flies was consistently observed after four days in the Petri dishes containing OE-NaClO' orange peel extract compared to the hydrogel control side (paired t-test, p < 0.0001, N = 10; see Fig. 5A); the graph in Fig. 5A shows the number of dead spotted wing drosophila. The application of the inventive orange peel extract OE-NaClO' led to a significant reduction in the number of larvae in the grape berries positioned above the Petri dish containing OE-NaClO' orange peel extract compared to the grape berries above the hydrogel (paired t-test, p < 0.05, N = 10; see Fig. 6); the graph shows the number of larvae per 10 grape berries. To analyze the time-dependent insecticidal effect of OE-NaClO' orange peel extract, the daily number of dead fruit flies was recorded throughout the experiment.The average number of dead fruit flies in both Petri dishes for each day is shown in Fig. 5B (after 24 h, 48 h, 72 h, and 96 h). Approximately 50% of the D. suzukii flies died within the first 48 hours after exposure to the orange peel extract (Fig. 6B, N = 10). There was no significant increase in the number of dead flies more than three days after the start of the experiment.

[0091] In further choice trials, the insecticidal effect of freshly prepared OE-NaClO' orange peel extract was compared with OE-NaClO' orange peel extract prepared a few days previously. Fig. 7 shows the results of this choice trial, in which the effect of the freshly prepared orange peel extract according to the invention was compared with the effect of a 3-day-old and a 6-day-old orange peel extract according to the invention. The graph in Fig. 7 shows the number of dead spotted wing drosophila as a function of the orange peel extract used (fresh, 3-day-old, 6-day-old). As shown in Fig. 7, a slight decrease in the number of dead flies was observed when using the orange peel extract prepared 6 days before the start of the choice trial, in contrast to freshly prepared orange peel extract.

[0092] EXAMPLE 3 - Field trial

[0093] In this experiment, the attractant and insecticidal effects of an orange juice extract according to the invention were tested in the field.

[0094] 3.1 Materials and methods

[0095] 3.1.1 Production of the orange peel extract according to the invention

[0096] Orange peel extract OE-NaClO-EtOHlO': The peels of 4 oranges (180 g orange peels) were cut into small pieces and placed in 500 ml of an extraction solution consisting of double-distilled water with 10 w / v% NaCl and 10 v / v% ethanol for 24 hours at room temperature in a dark place. The orange peels were then removed from the NaCl-EtOH extraction solution and, after removing excess NaCl extraction solution, pressed through a garlic press in a first pressing step. The juice obtained in the first pressing step was then pressed through a fine-mesh cloth into a container in a second pressing step to remove any remaining orange peel particles. The resulting liquid is an orange peel extract (OE-NaClO-EtOHlO') according to the invention.

[0097] 3.1.2 Conducting the field trial

[0098] DrosalPro fruit fly traps (purchased from Andermatt Biogarten) were filled with different types of food:

[0099] • Trap A) 10 mL DrosaLure™ (positive control). DrosaLure™ is a commercially available fruit fly attractant.

[0100] • Case B) Hydrogel (carrier) + 2 ml orange peel extract OE-NaClO-EtOEIlO' (according to the invention)

[0101] • Case C) hydrogel only (negative control)

[0102] The hydrogel (herein also referred to as water gel) was prepared with 0.5 g of Aqua-Water granules Terrabest (Feeders & more GmbH, Germany) and 43 mL of double distilled water.

[0103] Traps A), B), and C were hung outdoors in a cherry tree (wild bird cherry) next to Leechgasse 42, 8010 Graz, Austria. The traps were removed after 7 days, and the dead flies in traps A), B), and C were counted. Weather data (temperature, precipitation, sunshine duration) for these 7 days were recorded for documentation purposes (measuring station of the University of Graz).

[0104] 3.2 Results

[0105] The result of the field trial is shown in Fig. 9. After a period of seven days in the field, the number of dead D. suzukii flies in trap B) containing the orange peel extract OE-NaClO-EtOEIlO' (Fig. 9: "Orange peel extract") was significantly higher than in trap C) filled with pure hydrogel (negative control) and in trap A) filled with the commercially available product DrosaLure™ (positive control). 4. Summary

[0106] As the experimental results of Examples 1, 2, and 3 demonstrate, the efficacy of orange peel extracts according to the invention depends primarily on two key properties: attraction (attractive effect) and toxicity. Both properties are evidently high for D. suzukii, as clearly demonstrated by the high number of fly deaths upon contact with the orange peel extracts according to the invention, in contrast to the low number of flies killed upon contact with the water gel control (cf. Example 1 / Fig. 1A, 1B; Example 2 / Fig. 4A, 4B, 5A, 5B).

[0107] In an attract-and-kill approach, orange peel extracts according to the invention can reduce the number of eggs laid in grapes in the field. This can be concluded from the significant reduction in larvae in grapes located near the orange peel extract Petri dish (see Fig. 6).

[0108] The results of the experiments show that the combination of substances in orange peels together with a high salt concentration (NaCl) has a lethal effect on D. suzukii. This is evident in the reduction in the number of dead fly individuals after 5 days, as shown in Example 1 / Figs. 2B and 2C, after the orange peel extract was diluted and the salt concentration was reduced. When the orange peel extract according to the invention was prepared 6 days before the start of the experiment, only a slight decrease in the number of dead fly individuals was observed compared to freshly prepared orange peel extract (cf. Example 2 / Fig. 7). This indicates that an orange peel extract according to the invention remains attractive to flies over a longer period of time, which is important for field application.The field trial according to Example 3 confirms the attractant and insecticidal activity of the orange peel extract according to the invention outside the laboratory environment and its usefulness in applications for the treatment of spotted wing drosophila infestation.

[0109] The invention is not limited to the described embodiments, but is defined by the entire scope of the claims. Individual aspects of the invention or the embodiments may also be adopted and combined with one another.

Claims

PATENT CLAIMS 1. A process for the preparation of an orange peel extract suitable for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), the process comprising the following steps: Step a) subjecting orange peels to extraction by placing the orange peels in an aqueous extraction solution containing at least 5 w / v% NaCl, and preferably up to 15 w / v% NaCl, for a predetermined period of time; and Step b) Separating the orange peel extract obtained by extraction from the orange peels.

2. Process according to claim 1, characterized in that the extraction according to step a) is carried out over a period of at least 2 hours.

3. The method according to claim 1 or 2, characterized in that in the separation process according to step b) the orange peels are removed from the aqueous extraction solution and then the removed orange peels are subjected to at least one pressing process in order to separate the orange peel extract from the removed orange peels.

4. A method according to claim 3, characterized in that in the separation process according to step b), the orange peels taken from the aqueous extraction solution are subjected to a first pressing process and a second pressing process following the first pressing process, wherein: in the first pressing process, the taken orange peels are pressed by a first pressing device, whereby a pressed product comprising orange peel extract and orange peel parts is obtained, and In the second pressing process, the pressed product obtained in the first pressing process is pressed through a second pressing device, whereby the orange peel extract is separated from the orange peel parts.

5. Process according to one of claims 1 to 4, characterized in that the aqueous extraction solution contains 5 - 15 w / v% NaCl, preferably 8 - 12 w / v% NaCl.

6. Process according to one of claims 1 to 5, characterized in that the aqueous extraction solution contains approximately 10 wt / vol% NaCl.

7. Process according to one of claims 1 to 6, characterized in that the aqueous extraction solution additionally contains 5-10 vol. / vol.% ethanol.

8. Process according to one of claims 1 to 7, characterized by a step c) following step b) in which 1-10 vol. / vol.% vinegar and / or 1-5 vol. / vol.% red wine are added to the orange peel extract obtained in step b).

9. A process for the preparation of an orange peel extract suitable for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), the process comprising the following steps: Step aa) subjecting orange peels to extraction by soaking the orange peels in water for a predetermined period of time; Step bb) separating an aqueous extract obtained in step a) by means of extraction from the orange peels, and Step cc) Adding NaCl to the aqueous extract separated in step bb) in a concentration of at least 5 w / v% NaCl, and preferably up to 15 w / v% NaCl, to obtain the orange peel extract.

10. The method according to claim 9, characterized in that the extraction according to step aa) is carried out over a period of at least 2 hours.

11. The method according to claim 9 or 10, characterized in that in the separation process according to step bb) the orange peels are removed from the water and then the removed orange peels are subjected to at least one pressing process in order to separate the aqueous extract from the removed orange peels.

12. The method according to any one of claims 9 to 11, characterized in that in step cc) 5 - 15 wt. / vol.% NaCl, preferably 8 - 12 wt. / vol.% NaCl, are added.

13. Process according to one of claims 9 to 12, characterized in that in step cc) approximately 10 wt / vol% NaCl is added.

14. The method according to any one of claims 9 to 13, characterized by a step dd) following step cc) or a step dd) taking place simultaneously with step cc), wherein in step dd) 1-10 vol. / vol.% vinegar and / or 1-5 vol. / vol.% red wine and / or 5-10 vol. / vol.% EtOH are added to the orange peel extract obtained in step cc) in step dd).

15. Orange peel extract for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), prepared by a process according to any one of claims 1 to 14.

16. An insecticide for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), containing or consisting of an orange peel extract prepared by a process according to any one of claims 1 to 14.

17. Trap (1) for attracting and killing fruit flies, in particular spotted wing drosophila (Drosophila suzukii), comprising: • a closed housing (2) with at least one through-opening (3) and an inner region (4), wherein the at least one through-opening (3) is designed and dimensioned so that fruit flies, in particular spotted wing drosophila (Drosophila suzukii), can pass from the outside through the at least one through-opening (3) into the inner region (4) of the closed housing (2), whereas larger non-target organisms cannot pass through at least one passage opening (3), and • a predetermined amount of an orange peel extract (5) according to claim 15 or an insecticide according to claim 16 arranged in the interior region (4) of the closed housing (2).

18. Trap for attracting and killing fruit flies according to claim 17, characterized in that the predetermined amount of orange peel extract (5) is applied to or embedded in a carrier material (6).

19. Trap for attracting and killing fruit flies according to claim 17 or 18, characterized in that it is at least partially colored red.

20. Use of an orange peel extract prepared by a process according to any one of claims 1 to 14 as an insecticide.

21. Use according to claim 20, as an insecticide against spotted wing drosophila (Drosophila suzukii).

22. Use of an orange peel extract prepared by a process according to any one of claims 1 to 14 as an agent for attracting and killing fruit flies.

23. Use according to claim 22, as an agent for attracting and killing spotted wing drosophila (Drosophila suzukii).

24. Use according to any one of claims 19 to 23, characterized in that the orange peel extract is applied in undiluted form.

25. Use according to any one of claims 19 to 24, characterized in that the orange peel extract is applied to or embedded in a carrier material.

26. Use according to any one of claims 19 to 25, wherein a trap for attracting and killing fruit flies according to any one of claims 17 to 19 is used. A method for attracting and killing fruit flies, in particular for attracting and killing spotted wing drosophila (Drosophila suzukii), wherein one or more of the traps according to claim 17 or 18 are arranged at locations which are located within or near plants infested with fruit flies, in particular plants infested with spotted wing drosophila (Drosophila suzukii), or which are located within or near plants which are at risk of being infested with fruit flies, in particular with spotted wing drosophila (Drosophila suzukii).

28. A method for attracting and killing fruit flies according to claim 27, wherein the fruit flies are spotted wing drosophila (Drosophila suzukii).

29. Method according to claim 27 or 28, characterized in that the orange peel extract is applied in undiluted form.

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