Technical field

The technology proposed herein relates generally to the field of deterrent compositions and methods for deterring pests. More particularly the technology proposed herein concerns deterrent compositions comprising aldehydes, in particular, (Z)-4-undecenal, for deterring flies, in particular Drosophila suzukii, the spotted wing Drosophila.

Background

Damage caused by pests, such as flies, can have significant economic consequences for farmers growing inter alia fruits and berries. Such pests may inter alia feed on parts of the fruits or berries, or deposit eggs that develop into larvae that feed on or in the fruits or berries. In both cases the affected fruits and berries become damaged, and therefore decrease in attractiveness and value from a consumer perspective. The damage brought upon the berries or fruits by the pests may additionally allow or promote further damage, such as from other pests, microorganisms, or diseases, thus leading to further economic loss for the farmers. Conversely, some pests, including flies, only affect, e.g. feed on and lay eggs on and in, already damaged or overripe fruits. One such pest is the drosophilid fly Drosophila melanogaster.

Another Drosophila fly, Drosophila suzukii (also known as spotted wing drosophila), originating from Asia, has since the year 2008 invaded the Americas, Europe and Africa, thereby causing devastating economic cost for farmers each year. Unlike most drosophilid flies, like the above-mentioned Drosophila melanogaster which infest overripe and damaged fruit, female Drosophila suzukii puncture the fruit skin, using a serrated ovipositor, to insert eggs (oviposit) into, and damage, fresh ripening fruits. Larvae develop in the pulp before harvest. The developing larvae consume the fruit flesh resulting in collapse of the fruits. Secondary infestations by fungi and bacteria, as well as other insects is common. This makes Drosophila suzukii more difficult to control, and this initial damaging of undamaged, ripening fruits further, as discussed above, facilitates and increases the risk of other pests attacking the fruit or berry. Moreover, Drosophila suzukii also infests stored fruit post-harvest. Irrelevant if infested pre- or post-harvest, developing larvae make fruit non-marketable. Fruits affected include strawberries, cherries, blueberries, raspberries, blackberries, peaches, nectarines, apricots, kiwi, grapes, and other soft fruits. Measures for prevention and suppression of damage include harvest before ripeness, use of insect nets and strict sanitary measures such as destruction of infested fruits. However, these control methods for example can only be applied for certain fruits, are costly and not always practical.

Pesticides have also been used for controlling Drosophila suzukii. EP3488695A1 thus discloses pesticide compositions comprising one or more pesticide volatile organic compounds made up from branched or cyclic alkanes or alkenes. As shown in Fig. 1B of this document, various compounds were effective in killing Drosophila suzukii flies Pesticides are however generally, due to their toxicity, less desirable to use close to, or on, fruits intended for human consumption. It is further difficult to target larvae inside the fruit with a pesticide. There is also a risk of pesticides killing or affecting (non-target) species other than the target species to be controlled by the pesticide. Further, in order to get an effect, i.e. a killing of the pests, an effective amount of the pesticide has to be provided to the species to be controlled by the pesticide.

There is accordingly a need for further methods, uses, and compositions that can be used to protect fruit from infestation by Drosophila suzukii.

Object of the Technology

It is accordingly a first object of the technology proposed herein to provide methods and uses for deterring Drosophila suzukii, in particular for deterring Drosophila suzukii from ovipositioning.

It is a further object of the technology proposed herein to provide a deterrent composition for deterring Drosophila suzukii.

It is yet a further object of the technology proposed herein to provide a device for deterring Drosophila suzukii.

Summary

At least one of the abovementioned objects, or at least one of the further objects which will become evident from the below description, is according to corresponding first and second aspects of the technology proposed herein obtained by a method of deterring Drosophila suzukii, comprising providing an effective dose of c/s-4- undecenal, or a precursor yielding c/s-4-undecenal through autoxidation, at a location from which Drosophila suzukii should be deterred, and the use of c/s-4-undecenal, or a precursor yielding c/s-4-undecenal through autoxidation, for deterring Drosophila suzukii.

Accordingly, the technology proposed herein is based on the discovery, as validated in Example 1 , that c/s-4-undecenal significantly decreases the oviposition of Drosophila suzukii. In other words, fewer eggs are laid in fruits in locations provided with c/s-4- undecenal. This decrease in oviposition is significant, both in comparison with ethanol (controls) and in comparison, with the general aldehyde trans- 2-undecenal.

The method and use according to the corresponding first and second aspects of the technology proposed herein provides for deterring Drosophila suzukii, thereby providing a way of reducing and/or preventing the problem of Drosophila suzukii infestations.

Below, features applicable to both the first and second aspects of the technology proposed herein will be discussed.

Deterring Drosophila suzukii encompasses one or more of at least partially keeping Drosophila suzukii away from the location, reducing the attractiveness of the location to Drosophila suzukii, reducing the number of Drosophila suzukii in the location, and reducing the tendency of Drosophila suzukii to oviposit in the location.

Preferably, deterring Drosophila suzukii comprises or consists of deterring Drosophila suzukii from ovipositioning, such as reducing the tendency of Drosophila suzukii to oviposit, at or in, the location.

The c/s-4-undecenal, or a precursor as described further below, may be provided in solid phase, liquid phase or in gas phase in the location.

An effective dose of c/s-4-undecenal is a dose sufficient to deter Drosophila suzukii in or from the location. The effective dose will depend on the size of the location and the manner in which the c/s-4-undecenal is provided at the location. One of ordinary skill in the art will be able of determining an effective dose on the basis of the examples and the embodiments discussed further below, and on the basis of observing whether Drosophila suzukii is deterred from the location.

Where the c/s-4-undecenal is provided as a precursor as described further below, then an effective dose of the precursor is a dose sufficient to provide, through autoxidation of the precursor, an effective dose of c/s-4-undecenal as described above. C/s-4-undecenal is also known as (Z)-4-undecenal, c/s-Undec-4-enal, (Z)-undec-4-enal, or Z4-11AI. It has the CAS number 68820-32-6, the molecular formula C11H20O and a molecular weight of 168.28 g/mol. The structural formula is given as formula I below:

The location may comprise any location in which fruits are grown, handled, transported, or stored. The location may for example comprise an individual fruit, a fruit bearing plant or bush, a fruit tree, a garden, an orchard, a greenhouse, all or a portion of a processing plant for handling, processing and/or packing the fruits, etc.

Additionally, the location may comprise a bag, box, or other container into which harvested fruit is to be placed, or has been placed, for example for transporting and/or storing the fruit. This includes freight containers carried by road vehicle, ship or plane, as well as holds on ships in which fruit has been, or will be, placed.

The c/s-4-undecenal may be provided at the location by providing c/s-4-undecenal perse at the location, or by providing a precursor yielding c/s-4-undecenal through autoxidation at the location.

The precursor can be any linear aliphatic compound with at least 13 carbon atoms and comprising Z double bonds at carbon atoms N and N+4 that is capable of yielding c/s-4- undecenal through autoxidation. One example is (Z,Z)- 7,11 tridecadiene.

The precursor is preferably a (Z,Z,Z)-7,11,15-triene, such as (Z,Z,Z)- 7,11,15- docosatriene, or a (Z,Z)-7, 11 diene such as (Z,Z)-7, 11 -octadecadiene or (Z,Z)-7, 11 - heptacosadiene.

The precursor preferably yields c/s-4-undecenal in one reaction step of autoxidation.

The rate at which the precursor autoxidizes depends on the temperature and partial pressure of oxygen in the location. Preferred precursors are those that autoxidizes at a rate sufficient so that that at least 1% of the precursor has autoxidized yielding c/s-4- undecenal after 2 hours in the location, alternatively at least 1% of the precursor has autoxidized yielding c/s-4-undecenal after 1 hours in the location.

Preferably the method and corresponding use comprises deterring Drosophila suzukii from fruits provided at the location. The fruits are preferably ripening or ripe fruits. Preferably the fruits are selected from the group consisting of strawberries, cherries, blueberries, raspberries, blackberries, peaches, nectarines, apricots, kiwi, and grapes.

Preferably the method and corresponding use comprises deterring Drosophila suzukii from ovipositioning on the fruits.

Preferably the c/s-4-undecenal is provided at a dose of at least 0.1 ng c/s-4-undecenal per g fruits, preferably at least 0.5 ng c/s-4-undecenal per g fruits, more preferably at least 1 ng c/s-4-undecenal per g fruits.

In example 1 and 2, the dose used was 1.18 or 1.23 ng c/s-4-undecenal per g fruits, which provided a clear deterring effect of Drosophila suzukii, as noted in the decreased oviposition on the berries. These dosages thus provide examples of an effective dose of c/s-4- undecenal. Depending on the weight amount of fruit in the location, the total amount of cis- 4-undecenal provided in the location may be adjusted according to these dosages.

Alternatively, or additionally, the c/s-4-undecenal is provided at a dose of at least 0.7 pg cis- 4-undecenal per m ² of fruit surface area, preferably at least 3.5 pg c/s-4-undecenal per m ² of fruit surface area, more preferably at least 7 pg c/s-4-undecenal per m ² of fruit surface area.

In example 1 and 2, the dose used was 7.8 or 8.1 pg c/s-4-undecenal per m ² of fruit surface area, and this provided a clear deterring effect of the Drosophila suzukii, as noted in the decreased oviposition on the berries.

These dosages thus provide examples of an effective dose of c/s-4-undecenal.

Where a precursor yielding c/s-4-undecenal is used as described above, then the dose of the precursor is preferably selected so as to provide the abovementioned dosages of c/s-4- undecenal.

The c/s-4-undecenal or the precursor is preferably applied to the vegetation canopy of the plants, bushes or trees carrying the fruits, or to a bag, box, or other container in which the fruits are placed for transport and/or storage.

The c/s-4-undecenal or the precursor may alternatively be applied, such as by spraying or dipping, in or at the location, such as by spraying or dipping the fruits.

Spraying may be used for applying the c/s-4-undecenal or the precursor to fruits still attached to plants, bushes or trees, whereas spraying or dipping may be applied to fruits that have been harvested, such as prior to the fruits being stored for later marketing and consumption. C/s-4-undecenal or the precursor may be sprayed using conventional spraying equipment, if needed dissolved in a suitable solvent, i.e. as the composition according to the third aspect of the technology proposed herein. Likewise, c/s-4- undecenal or the precursor, if needed dissolved in a suitable solvent, i.e. as the composition according to the third aspect of the technology proposed herein, may be provided in a conventional container or bath into which the fruits are dipped. The c/s-4- undecenal or the precursor may inter alia be applied to fruits being transported on a conveyor, mixed with fruits in a mixer or funnel, applied to fruits in storage or fruits being transported, etc.

In a further alternative, the c/s-4-undecenal or the precursor is provided in a dispenser arranged at the location, the dispenser being configured to release the c/s-4-undecenal or the precursor.

This provides an alternative to applying the c/s-4-undecenal or the precursor to the vegetation canopy or bag, box, or other container, and to applying the c/s-4-undecenal to the fruit itself. In line with the above, the dispenser may for example be arranged in a bag, box, or other container in which the fruits are placed for transport and/or storage. Providing the precursor or the c/s-4-undecenal in a dispenser may prolong the effect of the c/s-4- undecenal.

The dispenser may comprise a source of c/s-4-undecenal or the precursor, such as a container or absorbent body holding c/s-4-undecenal or the precursor, and dispensing device, such as a nozzle or outlet in contact with the source, for releasing the c/s-4- undecenal or the precursor. The dispensing device may further comprise a semipermeable membrane or septa for releasing the c/s-4-undecenal or the precursor.

The dispenser may additionally comprise a pump or other means, such as a source of pressure, for pumping or pressuring the c/s-4-undecenal or the precursor from the source of c/s-4-undecenal or precursor to the dispensing device. In these cases, the dispenser preferably further comprises a control device for controlling actuation of the pump or other means, and/or the dispensing device, in order to provide the effective dose. The control device may inter alia comprise a clock device for controlling actuation at regular times, and for predetermined periods, to provide the efficient dose. Alternatively, or additionally, the control device may comprise a sensor for determining conditions at the location and for controlling the actuation depending on the conditions determined. The conditions may include one or more parameters such as temperature, light level, wind, and concentration of c/s-4-undecenal in the atmosphere in the location, or information about pest abundance. The control device my further comprise an interface for receiving remote commands enabling remote actuation. Additionally or alternatively, the source of c/s-4-undecenal or the precursor and the dispensing device, i.e. the dispenser, may comprise a rigid or non-rigid container, such as a sachet, having a wall defining an interior volume for holding c/s-4-undecenal or the precursor, where at least a section of the wall is permeable to the c/s-4-undecenal or the precursor. The dispenser may therefore for example comprise a plastic bag, sachet, or tube, for example made from polyethylene or other material permeable to c/s-4-undecenal or the precursor.

Alternatively, the c/s-4-undecenal or the precursor is provided by being synthesized by a plant or microorganism, more preferably a yeast or other microorganism, provided at the location, the genome of the plant or microorganism comprising a gene causing the plant to produce and release c/s-4-undecenal or the precursor. Suitable plants could inter alia include plants in the onion genus Allium and various herbs.

At least one of the abovementioned objects, or at least one of the further objects which will become evident from the below description, is according to the third aspect of the technology proposed herein further obtained by a deterrent composition for deterring Drosophila suzukii, the deterrent composition comprising c/s-4-undecenal or a precursor yielding c/s-4-undecenal through autoxidation, dissolved in a solvent, wherein the precursor is as described above and preferably is a (Z,Z,Z)-7, 11,15-triene, such as (Z,Z,Z)-7,11,15-docosatriene, or a (Z,Z)-7,11 diene such as (Z,Z)-7,11-octadecadiene or (Z,Z)-7, 11 -heptacosadiene.

The deterrent composition according to the third aspect of the technology proposed herein is advantageously used in the method and use according to the corresponding first and second aspects of the technology proposed herein.

The deterrent composition is preferably an ovipositional deterrent or ovipositional repellant.

The solvent is preferably selected from the group consisting of ethanol, acetone, benzene, carbon tetrachloride, diethyl ether, ethylene glycol, polyethylene glycol, glycerol, nitromethane, pyridine, and toluene.

Of these solvents, ethanol is preferred as it is readily available and generally safe.

Preferably, the composition comprises at least 0.1 mg/liter, preferably at least 0.5 mg/liter, more preferably at least 1 mg/liter of c/s-4-undecenal, or alternatively, the composition comprises an amount of the precursor that, upon autoxidation, yields at least 0.1 mg/liter, preferably at least 0.5 mg/liter, more preferably at least 1 mg/liter of c/s-4-undecenal.

1 mg/liter corresponds to the 1 ng/pL used in the examples.

The deterrent composition may preferably further comprise a viscosity-increasing compound, which when included in the deterrent composition increases the viscosity of the deterrent composition.

This is advantageous in that it increases the tendency of the deterrent composition to adhere to a surface, such as the surface of a fruit or other plant material such as the vegetation canopy, or to a surface such as the surface of a bag, box or other container in which the fruit is transported and/or stored. This eases the application of the deterrent composition and increases the longevity, as the deterrent composition is less affected by rain and winds, as well as physical contact with other fruits, leaves, and plant parts. In addition, a viscosity increasing compound would limit the release rate of the c/s-4- undecenal or the precursor, thus slowing down the release rate and thereby prolonging the effect of the deterrent composition. In particular, the addition of the viscosity- increasing compound may allow the deterrent composition to be formulated with a concentration of c/s-4-undecenal or precursor that is higher than ideally released, but which however, due to the lower release rate, is still released to provide an effective dose of c/s-4-undecenal, however, over a longer time.

Suitable viscosity-increasing compounds include polyethylene glycol, glycerol, waxes, oils, biopolymers such as polysaccharides, e.g., starch and cellulose, etc.

The solvent may alternatively comprise or consist of the viscosity-increasing compound. The c/s-4-undecenal or the precursor may thus be dissolved in the viscosity-increasing compound. One example is when the c/s-4-undecenal or the precursor is dissolved in for example polyethylene glycol or glycerol.

The deterrent composition may be formulated as a micro-emulsion, wherein the c/s-4- undecenal or the precursor is contained in polymeric micro-beads dispersed in a liquid matrix, i.e. , a solvent.

The deterrent composition may comprise one or more of a UV-stabilizer, an antioxidant and a surfactant. A UV-stabilizer is a compound which when included in the deterrent composition decreases breakdown of c/s-4-undecenal or the precursor. An antioxidant is a compound that decreases the rate of oxidation of the c/s-4-undecenal or the precursor.

The deterrent composition may be solid. This may be caused by providing a suitable viscosity-increasing compound at a suitable concentration. To render the deterrent composition solid a polyethylene glycol with a high viscosity and a high molecular weight may for example be used. Alternatively, a wax may be used to render the deterrent composition solid.

A solid deterrent composition may for example be easily provided in a dispenser or attached to a plant or scattered over or around fruits. This may be advantageous as it allows the c/s-4-undecenal or the precursor to be provided at a location while being separate from fruit at that location.

Alternatively, or additionally, the deterrent composition may comprise the c/s-4-undecenal or the precursor in encapsulated form. The c/s-4-undecenal or the precursor, with or without solvent, may thus be encapsulated. Possible encapsulants include inter alia starch matrices, various polymeric coatings, oil-in-water emulsions, and lipid nanoparticles.

It is further noted within the context of the technology proposed herein that (Z,Z,Z)- 7,11,15-docosatriene and (Z,Z)-7,11-octadecadiene may be especially advantageous as a precursor as it forms c/s-4-undecenal from both ends during autoxidation. Accordingly, one further aspect of the technology proposed herein thus concerns a deterrent composition comprising (Z,Z,Z)-7,11,15-docosatriene or (Z,Z)-7,11-octadecadiene.

Preferably, the deterrent composition contains at least 0.5 g, such as at least 1 g, c/s-4- undecenal or precursor. Accordingly, a dose of the deterrent composition according to the third aspect of the technology proposed herein may contain at least 0.5 g, such as at least 1 g, c/s-4-undecenal or precursor.

Although it is preferred to include a solvent in the deterrent composition, this solvent may be dispensed with. In such cases the deterrent composition comprises c/s-4-undecenal or a precursor yielding c/s-4-undecenal through autoxidation as described above, and at least one of: a) the above-described viscosity-increasing compound, or b) the above-described UV-stabilizer, antioxidant and/or surfactant.

At least one of the abovementioned objects, or at least one of the further objects which will become evident from the below description, is according to the fourth aspect of the technology proposed herein further obtained by a device for deterring Drosophila suzukii, the device comprising or releasing c/s-4-undecenal or a precursor yielding c/s-4- undecenal through autoxidation, wherein the precursor preferably is a (Z,Z,Z)-7, 11,15- triene, such as (Z,Z,Z)-7,11,15-docosatriene, or a (Z,Z)-7,11 diene such as (Z,Z)-7,11- octadecadiene or (Z,Z)-7,11-heptacosadiene. Preferably the device comprises or releases the deterrent composition according to the third aspect of the technology proposed herein.

Preferably the device comprises a dispenser configured to release the c/s-4-undecenal or the precursor as vapor or gas.

The dispenser may be configured as described above.

The dispenser may further comprise a solid carrier in which the c/s-4-undecenal or the precursor is incorporated by adsorption or absorption. The solid carrier may for example comprise a porous, elastic or rigid, material. Suitable materials include porous ceramics and porous foams, or porous fibers. The carrier may release the c/s-4-undecenal or the precursor spontaneously, or alternatively be heated or otherwise affected to release the c/s-4-undecenal or the precursor.

Preferably the device comprises a dispenser comprising a rigid or non-rigid container having a wall defining an interior volume holding c/s-4-undecenal or the precursor, where at least a section of the wall is permeable to the c/s-4-undecenal or the precursor.

The container may for example be configured as a plastic bag, sachet, or tube made from polyethylene or other material permeable to c/s-4-undecenal or the precursor.

The device may accordingly comprise a polyethylene tube, a polyethylene sachet, a polyethylene vial, a membrane dispenser, a spiral polymer dispenser, a polymer film, a rubber septum, a rubber wick, polyvinyl chloride, a hollow fiber, or an impregnated rope, wherein the c/s-4-undecenal or the precursor in each case is placed within the device and allowed to permeate, or wherein the device has absorbed the c/s-4-undecenal or the precursor.

Preferably the device is configured to release an effective dose of c/s-4-undecenal or the precursor for deterring Drosophila suzukii at a location from which Drosophila suzukii should be deterred.

More preferably the device is configured to release c/s-4-undecenal or the precursor at a dose which is not more than 10 times, preferably not more than 5 times, more preferably not more than 2 times, the effective dose of c/s-4-undecenal or the precursor for deterring Drosophila suzukii at a location from which Drosophila suzukii should be deterred. Preferably the device contains at least 0.5 g, such as at least 1 g, c/s-4-undecenal or precursor.

The dispenser may release the c/s-4-undecenal or the precursor by comprising the c/s-4- undecenal or the precursor. The dispenser may thus release and comprise the cis-4- undecenal or the precursor.

Brief description of the drawings and detailed description

A more complete understanding of the abovementioned and other features and advantages of the technology proposed herein will be apparent from the following detailed description of preferred embodiments in conjunction with the appended drawings, wherein:

Fig. 1 shows the mean number of eggs laid by mated female (n=54) of Drosophila suzukii after 24 h in a dual-choice assay on blueberries treated with either 5 ng of c/s-4-undecenal (Z4-11AI; dissolved in 5 pi ethanol) or 5 mI_ of ethanol (EtOH) as a control.

Fig. 2 shows the mean number of eggs laid by mated female (n=37) of Drosophila suzukii after 24 h in a dual-choice assay on blueberries treated with either 5 ng of c/s-4-undecenal (Z4-11 Al) or 5 ng trans- 2-undecenal (£2-11AI) as a control. The assay was conducted in a Petri-dish (1 female/Petri-dish). The number of eggs was used as a proxy for oviposition preference and was analyzed by ANOVA (F=4. 465; *p= 0.038).

Fig. 3A shows a dispenser being used to deter Drosophila suzukii from apples on an apple tree.

Fig. 3B shows the dispenser in Fig. 3A in closer detail.

Fig. 3C shows an alternative dispenser.

In the figures and the description, the same reference numeral is used to refer to the same feature. A ’ added to a reference numeral indicates that the feature so referenced has a similar function, structure or significance as the feature carrying the reference numeral without the ’, however not being identical with this feature.

Example 1: c/s-4-undecenal (Z4-11AI) decreases oviposition by Drosophila suzukii on blueberries Methods and materials

Drosophila suzukii (Italian strain) were acquired from an existing colony previously collected in Italy (Mori et al., Enhanced yeast feeding following mating facilitates control of the invasive fruit pest Drosophila suzukii. Journal of Applied Ecology, 54(1), 170-177, 2017). The colony was maintained in a quarantine lab on a standard Bloomington diet at a temperature of 25 ± 2°C and relative humidity (RH) of 50 ± 10%, under a 12:12 (L:D) photoperiod. Virgin flies were collected 4 h post-eclosion and sexed under gentle stream of CO2. Male and female flies were kept separately in new food vials until 4-6 days when they were mixed in a new food vial for mating. Mating couples were collected with a glass Pasteur pipette and relocated to an empty vial. The vials were plugged with a moisturized cotton ball. Successfully mated females were used for the experiments. Mating was considered successful when male and female were separated from each other.

To determine the effect of c/s-4-undecenal (Z4-11 Al) on oviposition preference of D. suzukii, a dual-choice assay was performed (n=54). For oviposition substrates, blueberries were purchased from a local grocery store. Prior to use, the surface area and weight for each blueberry were determined. To determine the surface area, height and diameter of the blueberries were measured using a caliper ruler. Weight was determined using a weighing balance (Precisa 4000 C, Precisa Gravimetrics AG, Switzerland). Additionally, the blueberries were graded according to ripeness and washed in deionized water and dried before use. To minimize variations due to size and weight of the blueberries, the substrates of similar phenological characters (weight, size, and ripeness) were paired in a glass Petri- dish (VWR 216-0073) (diameter = 115 mm, height = 65 mm). 5 pL of Z4-11AI (1 ng/pL, dissolved in ethanol) were applied on the surface of the blueberries. 5 pL of ethanol was added to the control blueberries. Two blueberries, i.e. a Z4-11AI-treated and a control blueberry were arranged approximately 80 mm a part in one of the glass Petri-dishes. Mated females of D. suzukii were introduced, using a Pasteur-pipette, into the Petri-dishes (1 female/Petri-dish) and covered with a perforated lid. To minimize variation due to first contact, the females were placed in the middle of the Petri-dishes at equidistance from the berries.

The number of eggs was used as a proxy for oviposition preference and was analyzed by Analysis of variance (ANOVA).

Results

The mean weight and surface area of berries were as follows:

As shown in Fig. 1 , the mean number of eggs laid by mated females (n=54) of Drosophila suzukii after 24 h was significantly lower (F = 8.539, *p = 0.012) at 2.5 ± 0.5 eggs on blueberries treated with c/s-4-undecenal (Z4-11AI) as compared to the control blueberries (5.2 ± 0.8 eggs) treated with ethanol (EtOH).

Accordingly, treatment with c/s-4-undecenal (Z4-11AI) provided a deterring effect on the Drosophila suzukii flies (females) in that the number of eggs laid on the treated berries were significantly lower than on the control berries.

The dosing in this example was about 2.5 ng Z4-11AI per each blueberry, i.e. about 1.18 ng per gram blueberry. The corresponding dosage per surface area was 2.5 ng per 320.12 mm ² = 0,0078 ng per mm ² .

Example 2: Comparison of c/s-4-undecenal (Z4-11AI) and trans- 2-undecenal (E2-11AI)

Methods and materials

To determine if Z4-11AI and trans- 2-undecenal (E2-11AI) had different effect on the oviposition of D. suzukii, a second set of dual-choice experiments were conducted similar to the first dual-choice experiments (Example 1 above), except that blueberries treated with 5 pl_ of E2-11AI (1 ng/pL) were paired with Z4-11AI treated blueberries (5 pl_,1 ng/pL as above) (n=37). In both set-ups, the females were removed after 24 h, the number of eggs laid on the berries were counted under a microscope and used as a proxy for oviposition preference. ANOVA was used for statistical analysis.

Results

The mean weight and surface area of berries were as follows:

As shown in Fig. 2, the mean number of eggs laid by mated females (n=54) of Drosophila suzukii after 24 h was significantly lower (F = 4.465; *p = 0.038) at 1.3 ± 0.4 eggs on blueberries treated with c/s-4-undecenal (Z4-11AI) as compared to 2.5 ± 0.4 eggs on the blueberries treated with trans- 2-undecenal (E2-11AI).

Accordingly, treatment with c/s-4-undecenal (Z4-11AI) provided a significantly stronger deterring effect on the Drosophila suzukii flies (females) than trans- 2-undecenal (E2-11AI). The dosing in this example was about 2.5 ng Z4-11AI per each blueberry, i.e. about 1.23 ng per gram blueberry. The corresponding dosage per surface area was 2.5 ng per 307.33 mm ² = 0,0081 ng per mm ² .

Fig. 3A shows a dispenser 10 (shown in more detail in fig. 3B) being used to deter Drosophila suzukii from ripening apples 4 on an apple tree 2.

The dispenser 10 comprises an enclosure 12 defining an interior volume 14, a source 16 of c/s-4-undecenal placed within the enclosure 12, a dispensing nozzle 18 connected to the source 16 via a pump 20, the pump 20 alternatively being replaced by a suitable tubing and/or wick to deliver the c/s-4-undecenal passively through capillary forces or evaporation. The pump 20 receives power from a battery 22, said power being routed through a relay 24 controlled by a control device 26. The control device 26 is configured to close the relay 24 at specific times, for example at specific timer intervals, to thereby selectively actuate the pump 20 in order to dispense the c/s-4-undecenal.

Fig. 3C shows an alternative dispenser 10’ comprising a semipermeable wall 12’ defining an interior volume 14 in which c/s-4-undecenal 16’ is provided. C/s-4-undecenal continuously permeates through the wall 12’ to reach the outer side 28’ thereof, from which the c/s-4-undecenal evaporates. The alternative dispenser 10’ thus dispenses the c/s-4-undecenal only passively and spontaneously, in contrast to the dispenser 10 in which dispensing may be controlled by the control device 26.

Although figs 3A-3C refers to c/s-4-undecenal as being used in the respective dispenser, a precursor yielding c/s-4-undecenal through autoxidation could be used instead.

Feasible modifications

The technology proposed herein is not limited only to the embodiments described above and shown in the drawings, which primarily have an illustrative and exemplifying purpose. This patent application is intended to cover all adjustments and variants of the preferred embodiments described herein, thus the present invention is defined by the wording of the appended claims and the equivalents thereof. Thus, the equipment may be modified in all kinds of ways within the scope of the appended claims.

For instance, it shall be pointed out that structural aspects of embodiments of the method according to the first aspect of the technology proposed herein shall be considered to be applicable to embodiments of the system according to the second aspect of the technology proposed herein, and conversely, methodical aspects of embodiments of the system according to the second aspect of the technology proposed herein shall be considered to be applicable to embodiments of the method according to the first aspect of the technology proposed herein.

It shall also be pointed out that all information about/concerning terms such as above, under, upper, lower, etc., shall be interpreted/read having the equipment oriented according to the figures, having the drawings oriented such that the references can be properly read. Thus, such terms only indicate mutual relations in the shown embodiments, which relations may be changed if the inventive equipment is provided with another structure/design.

It shall also be pointed out that even though it is not explicitly stated that features from a specific embodiment may be combined with features from another embodiment, the combination shall be considered obvious, if the combination is possible.

Throughout this specification and the claims which follows, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or steps or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.