EA040826B1 - METHOD OF FIGHTING DROSOPHILA SUZUKII - Google Patents

Description

Field of invention

The present invention provides a method for controlling Drosophila suzukii, comprising the step of spraying or applying 9-tricosene to a crop or part of the crop, wherein the 9-tricosene inhibits mating. The 9-tricosene compound can be used alone or in combination with 7-tricosene for more effective control of Drosophila suzukii. In addition, the present invention provides for the use of specific methods of spraying using 9-tricosene.

State of the art invention

Drosophila suzukii (Matsumura) (Insecta: Diptera: Drosophilidae), trivially named Spotted Drosophila, is a highly invasive insect pest native to Southeast Asia. This species is classified as a pest due to its rapid reproduction and ability to harm ripening soft fruits such as cherries, blueberries and strawberries. Females are able to cut through the skin of the soft fruit with a sharp ovipositor, and then lay eggs inside. This can lead to losses of up to 80% of the crop, leading to potential economic shocks.

Although Drosophila suzukii has been reported throughout the Americas and Western Europe since 2008, no clear species-specific integrated pest management (IPM) strategy has been described. Many potential IPM strategies, such as attract and kill, mass trapping, and mating disruption, involve the use of pheromones. However, relatively little is known about pheromones in D. suzukii, and results obtained with the well-studied model organism Drosophila melanogaster are often different or even opposite to those obtained with D. suzukii. The most predominant pheromone among all Drosophila species is cis-11-octadepenyl acetate (cVA), a short-acting volatile sex pheromone. In Drosophila melanogaster, cVA is produced by males and transferred to females during mating. This causes courtship suppression by other Drosophila males. However, it has been found that Drosophila suzukii does not actually produce cVA.

Therefore, there is a continuing need to identify new products such as pheromones for pest control targeting Drosophila suzukii. As described in more detail hereinafter, the mating-inhibiting effect of 9-tricosene on Drosophila suzukii has never been disclosed or suggested in the art, making it a useful compound with particular advantages over currently used compounds that are attractants or deterrents to control this species.

Brief description of the invention

Surprisingly, it has been found that 9-tricosene can be used as a pest control agent and inhibits mating of D. suzukii. Therefore, in a first aspect, the present invention provides a method for controlling Drosophila suzukii, comprising the step of spraying or applying 9-tricosene to a crop or part of a crop. This finding is particularly surprising since 9-tricosene has recently been found to perform a completely different function in D. melanogaster. Indeed, male Drosophila melanogaster release the 9-tricosene pheromone when stimulated with food-scented apple cider vinegar. This pheromone acts as a powerful aggregating pheromone and as a signal for females to start laying eggs. It is also known that 9-tricosene acts as an aggregating pheromone and oviposition signal for some other insects such as mites and flies. Or to put it another way, in relation to Drosophila suzukii, 9-tricosene acts in a completely opposite way to what is currently known in the prior art.

Moreover, the compound 9-tricosene can be used alone or in admixture with 7-tricosene to control Drosophila suzukii in an even more effective manner. In addition, the present invention provides for the use of 9-tricosene spray methods that are useful in controlling Drosophila suzukii in a variety of cultures and environmental conditions.

Brief description of graphic materials

By specific reference to the figures, it is emphasized that the details shown are by way of example only and for the purpose of illustrative discussion of various embodiments of the present invention. They are included for the purpose of presenting what is considered the most applicable and readily available description of the ideas and conceptual aspects of the present invention. Therefore, no attempt is made to show the structural details of the present invention in more detail than is necessary for a fundamental understanding of the present invention. The description, taken in conjunction with the drawings, explains to those skilled in the art how several forms of the present invention may be practiced.

Fig. 1. Effect of 6 compounds on mating behavior (%) - influencing SNS courtship

Shows the effect of 6 compounds on the manifestation of mating behavior using 4-day-old wild-type males. (a) Shows the effect of the 6 cuticular hydrocarbons (CH) tested on courtship performance in 4 day old males of scented 1 day old females. (b) Shows the effect of the 6 tested SNs on the display of mating behavior in 4-day-old males after fragrance-treated 1-day-old males. (c) Shows the effect of 6 tested CHs

- 1 040826 on the manifestation of mating behavior in 4-day-old males for 4-day-old females treated with an aromatic agent. (d) Shows the effect of the 6 tested SNs on the display of mating behavior in 4 day old males after fragrance treated 4 day old males.

Fig. 2. Effect of 6 compounds on mating behavior (#) - influencing mating behavior SNS

In FIG. 2 shows the effect of 6 compounds on the average number of courtship attempts in 4 day old wild type males. (a) Shows the effect of the 6 tested SNs on the average number of courtship attempts in 4 day old males with fragrance treated 1 day old females. (b) Shows the effect of the 6 tested SNs on the average number of courtship attempts in 4 day old males for fragrance treated 1 day old males. (c) The effect of the 6 tested SNs on the average number of courtship attempts in 4-day-old males for fragrance-treated 4-day-old females is shown. (d) The effect of the 6 tested SNs on the average number of courtship attempts in 4-day-old males for fragrance-treated 4-day-old females is shown.

Fig. 3. Effect of 6 compounds on mating - influencing SNS mating

In FIG. 3 shows the effect of 6 compounds on copulation frequency between wild type 4 day old males and 4 day old females scented.

Detailed description of the invention

As described above, the present invention provides a method for controlling Drosophila suzukii, comprising the step of spraying or applying 9-tricosene to a crop or part of a crop. In a further embodiment, the present invention provides for the use of 9-tricosene to reduce reproduction, in particular by suppressing D. suzukii mating.

In a preferred embodiment, 9-tricosene, as used herein, refers to (Z)-9-tricosene, also known as cis-9-tricosene.

Moreover, the present invention provides a composition containing 9-tricosene, which can be used to control D. suzukii. In a further embodiment, the composition further comprises one or more other pest control agents such as insecticides, in particular other pest control agents directed against D. suzukii. This makes it possible to control Drosophila suzukii more effectively on different crops in different ways. Other suitable pest control agents to be used in the combined composition include, without limitation: a) insecticides (such as cyantraniliprole, spinosad, λ-cyhalothrin, acetamiprid) b) attractants used for tracking or mass trapping (e.g. mixtures apple cider and vinegar), or c) insect repellants. In a particular embodiment, the present invention contemplates a combination of 9-tricosene and 7-tricosene (particularly (Z)-7-tricosene), especially for the uses described herein.

The composition may contain additional ingredients such as one or more solvents and/or stabilizers. In a specific embodiment, the composition contains an anhydrous solvent, in particular selected from the group consisting of hydrocarbons, alcohols, ketones, ethers and esters. In a particular embodiment, the solvent is selected from the group consisting of n-hexane, n-pentane, acetone and paraffin oil.

In a particular embodiment, the composition containing 9-tricosene is used as a liquid formulation. In another embodiment, the present invention provides a 9-tricosene impregnated solid substrate for the uses described herein. In yet another embodiment, a dispenser containing 9-tricosene is used. For example, 9-tricosene can be sprayed with a dispenser that sprays 9-tricosene in a continuous manner or in a time-controlled manner, depending on the burden of Drosophila suzukii in the field or in the greenhouse. Alternatively, 9-tricosene is formulated so that it can be easily applied using standard sprays. Therefore, in a particular embodiment, the present invention provides a method for controlling D. suzukii comprising spraying a formulation containing 9-tricosene onto a culture or part of a culture. For example, a 9-tricosene formulation can be applied to fruit trees or plants to protect against D. suzukii. Alternatively, 9tricosene can be applied directly to maturing or ripe fruits. Preferred applications are agricultural fields and greenhouses, although the present invention can also be effectively applied to fruit storage areas.

Examples

Example 1

Drosophila suzukii adults were caught in the wild (Sint-Truiden, Limburg, Belgium). The flies were bred in quarantine rooms at 21°C on a medium of cornmeal, sucrose, yeast and agar.

All flies were collected within 12 hours of hatching, after which they were used to obtain specimens one day old or kept up to four days old. Four-day-old socially inexperienced flies were kept separately from the other sex, in contrast to the socially experienced flies, which

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Claims (5)

kept together with the other sex. Example 2 n-hexane (95%), n-geneicosane (98%), n-tricosane (98%), (Z)-7-tricosene (98%) and (Z)-9-tricosene (97%) were purchased from Thermo -Fischer and Sigma Aldrich. (Z)-5-Tricosene (99%) and 2-methyloctacosane (95%) were synthesized by the hired company Ecosynth (Ghent, Belgium). These compounds were dissolved in n-hexane (95%) and applied to the abdomen of Drosophila suzukii flies using brushes No. 2. Four day old flies were treated with an aromatic agent 24 hours before the test, one day old flies 1 hour before the test. Example 3 Behavioral analyzes were performed in a temperature controlled room (21° C.) and always at the same time (10 h 30 min). Fragrance-treated Drosophila suzukii flies were housed separately with a 4-day-old wild-type male Drosophila suzukii on a round plate (3 cm diameter). Each pair was filmed for 2 h due to the low activity rate of the species using Sony Handycams CX240. These videos were then analyzed for mating behavior and mating based on Mazzoni et al. 2013 (Plos One 8(11): e80708). Behavioral data were analyzed using a factor table followed by calculation of t-tests, as well as one-way ANOVAs for continuous data. Example 4 Behavioral experiments were carried out as follows. The flies were scented based on four different conditions: day old females, day old males, four day old females, and four day old males. These scented flies were paired with 4 day old wild type males. Subjects were assessed for both courtship and copulation modules. A fragrance solvent (n-hexane) was used as a control. In both courtship and mating, n-hexane showed no effect under any of the above conditions. Six different cuticular hydrocarbons were tested: n-geneicosane, n-tricosane, (Z)-5tricosene, (Z)-7-tricosene, (Z)-9-tricosene and 2-methyloctacosane. When considering the effect of these selected compounds on courtship performance, no significant differences were found under any of the 4 conditions tested (FIG. 1). This means that none of the connections seem to affect whether courtship is initiated or not. Even when courtship performance was not altered by any of the tested SNs, it was still possible that the number of courtship attempts was being modified. However, the results of the analysis demonstrated that the number of courtship attempts that occurred did not change for any of the tested SNs under any of the four conditions tested (FIG. 2). Moreover, this did not rule out possible effects on copulation frequency. Because copulation can only occur between fully mature males and females, aromatic-treated 4-day-old females were paired with wild-type 4-day-old males. Both 7-tricosene and 9-tricosene significantly reduced the frequency of copulations (Fig. 3). Thus, 9tricosene acts as a mating suppressant and is useful against D. suzukii. CLAIM 1. A method for controlling Drosophila suzukii, comprising the step of spraying or applying 9-tricosene to a crop or part of a crop. 2. The method of claim 1 wherein the 9-tricosene inhibits mating. 3. The method of claim 1 wherein the 9-tricosene is sprayed or applied in combination with 7-tricosene. 4. The method of claim 1, wherein the crop is a fruit tree or fruit plant. 5. The method according to claim 1, where the culture is a ripening or ripe fruit. -