EP4040966A1

EP4040966A1 - Method for reducing or obviating caterpillar plagues, such as caterpillars from the subfamily of thaumetopoeinae, such as thaumetopoea processionea or thaumetopoea pityocampa and kit-of-parts and aqueous composition for the method

Info

Publication number: EP4040966A1
Application number: EP20772449.3A
Authority: EP
Inventors: Jozef Wilhelmus Maria VANEKER
Original assignee: Onderwijs Van Hychem
Current assignee: Onderwijs Van Hychem
Priority date: 2019-09-12
Filing date: 2020-09-14
Publication date: 2022-08-17
Also published as: NL2023819B1; WO2021049943A1

Abstract

The invention relates to a method for reducing or obviating caterpillar plagues, comprising the step of applying an aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside to an area located on a tree. The invention further relates to a kit-of-parts and an aqueous composition for the method.

Description

Method for reducing or obviating caterpillar plagues, such as caterpillars from the subfamily of Thaumetopoeinae , such as Thaumetopoea processionea or Thaumetopoea pityocampa and kit-of-parts and aqueous composition for the method.

FIELD OF THE INVENTION

The invention relates to a method for reducing or obviating caterpillar plagues, such as caterpillars from the subfamily of Thaumetopoeinae, such as Thaumetopoea processionea or Thaumetopoea pityocampa. The invention further relates to a kit-of-parts and an aqueous composition for the method.

BACKGROUND OF THE INVENTION

Caterpillars from the Thaumetopoeinae subfamily, such as the Thaumetopoea processionea (or oak processionary) or Thaumetopoea pityocampa (or pine processionary) are caterpillars which reside on the exterior of trees (mainly on trees from the family of Fagaceae and Pinaceae, respectively), on which they build nests. The caterpillars are becoming more and more of a problem. From the third instar and onwards, the bodies of these caterpillars are covered with hairs, which are irritant to e.g. humans. Such hairs are also known as defensive bristles. Each caterpillar has huge numbers of hairs, for instance in the order of 10,000 to 50,000, with typical lengths of 0.1-0.3 mm. The caterpillar will actively release these hairs in case of stress. Even when the caterpillar has turned into a moth, the nest will remain on the tree, in which case the hairs may be released, e.g. due to wind.

The most common current approach to solve this, is the use of suction devices (somewhat similar to vacuum cleaners) to remove the nests. These devices are noisy in use, which increases the chance of hair release by the caterpillar, thereby making it necessary for users of these devices to wear protective clothing. This makes the removal a very lengthy and costly process. Furthermore, the waste from this process is hard to process because of the possibility of hair dispersion within waste processing companies.

Other methods comprise the use of the biological control agent Bacillus thuringiensis, i.a. sold under the trade name Xentari. This agent is detrimental to all micro-organic life around the tree. Therefore, the surroundings require a large amount of time to recover from such a treatment.

Another control method comprises the use of nematodes, which are believed to damage the gastrointestinal tract of the caterpillar, thereby causing the caterpillar to die before the third instar. This method is however very laborious and expensive. SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a more effective method for reducing or obviating caterpillar plagues (by e.g. removal of the caterpillar) than the methods currently employed and/or kit-of-parts or aqueous composition for this method. The method employed and/or kit-of-parts or aqueous composition for this method is preferably able to reduce or obviate the inconveniences caused by said caterpillars, in particular from plagues of these caterpillars and/or the effects of (excessive) hair release from these caterpillars.

This object is achieved with a method comprising the step of applying an aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside to an area located on a tree.

It has surprisingly been found that the combination of a strongly basic environment (e.g. from a pH of 11.0 or higher, preferably from a pH of 12.0 or higher) in combination with an alkyl polyglycoside is an effective remedy against various inconveniences caused by different types of caterpillars. Without restricting the scope of protection, it is conceived that the alkaline character of the composition causes protein coagulation and/or fat saponification. This reduces the inconveniences caused by the caterpillar by weakening the caterpillar. As a consequence, the caterpillars may die and/or may adhere, preferably including or comprising - where applicable - any hairs on or originating from these caterpillars. Alkyl polyglycosides improve the wetting properties of the alkaline aqueous composition and are more suitable than other surfactants, since these are able to tolerate an alkaline environment. Without restricting the scope of protection, it is conceived that the alkyl polyglycosides contribute to an increase in the viscosity of the solution in use, thereby increasing the contact time of the solution to an area treated. This increase may also decrease the rate absorption of the composition by a dense substrate (such as the trunk of a tree) in comparison to the caterpillar treated. Furthermore, the alkyl polyglycosides include structural elements - glycosides - that are corresponding to structural elements of the caterpillars in their skin and hairs. As a consequence, the alkyl polyglycoside appears to act as an adhesive, once that it gets into contact with the caterpillar.

The effect of an aqueous composition which is just strongly alkaline without the presence of the alkyl polyglycoside has been shown to be much less effective. If one would nonetheless use larger volumes of a merely strongly alkaline medium, a higher volume would be required. Such higher volume would increase the time necessary to treat a nest rather exponentially. In addition, the required amount would be so large that it would cause an increased chance of damage to the substrate on which the caterpillar is located, e.g. a tree. Moreover, the caterpillars or at least some of a plurality of caterpillars on a single tree might have a chance to escape, due to the larger time needed for the treatment with merely alkaline medium. The use of an aqueous composition with just an alkyl polyglycoside in a neutral environment has been shown to have no significant effect on caterpillars.

Alkyl polyglycosides are surfactants with a hydrophilic end, comprising a hydrophilic carbohydrate head group (e.g. a monoglycoside or a diglycoside, with the glycoside being selected from e.g. glucose, galactose, maltose, xylose or a-cyclodextrin or a mixture thereof) and a hydrophobic hydrocarbon tail, which is usually a primary saturated or unsaturated alcohol. When derived from glucose, these alkyl polyglycosides are also referred to as alkyl polyglucosides. Alkyl polyglycosides may contain more than one carbohydrate group at the hydrophilic end and/or may be composed of a mixture of alkyl homologues, oligomers, anomers and/or isomers. Alkyl monoglycosides are thus also be considered to be alkyl polyglycosides with just one glycoside unit.

The amount of alkyl polyglycoside is chosen between 0.1-5 percent by weight of the composition. Below this range, the amount of alkyl polyglycoside is too low to be effective. Above this range, the alkyl polyglycoside will cause excessive foaming of the composition.

The composition is an aqueous composition, i.e. a composition which, in addition to the ingredients specified according to the claims, mainly consists of water. The composition may be supplemented by the typical ingredients for these kinds of compositions, but in most typical cases the composition consists, except for the ingredients specified according to the claims, of more than 80 percent by weight, preferably more than 90 percent by weight, more preferably more than 95 percent by weight and most preferably more than 99 percent by weight of water. Water will typically be selected from waters with a salinity of fresh water, e.g. drinking water, or less.

For as far as relevant, it is observed that the method according to the invention should not be considered a method for treatment of an animal body by therapy practiced on the animal body. The method is not such a treatment, since it does not have a therapeutic effect on the animal concerned. The effect of the method may be even considered antitherapeutic (i.e. bringing a body into a less healthy state than before the application of the method).

In a preferred embodiment, the one or more caterpillars are from the subfamily of Thaumetopoeinae, such as Thaumetopoea processionea or Thaumetopoea pityocampa.

While the invention is currently not restricted to the use on caterpillars from this subfamily - use in order to destruct caterpillars from the subfamily of Cydalima perspectalis (or box tree caterpillar), which are notorious for its ability to virtually clear-cut plants of the family of Buxaceae in ample time, may also be successful - it has been in particularly found effective for the use on caterpillars from the subfamily of Thaumetopoeinae, such as Thaumetopoea processionea or Thaumetopoea pityocampa, e.g. because of the interaction between the composition and the hairs of the caterpillars from this subfamily.

In another preferred embodiment, the aqueous composition comprises from 0.3 to 0.7, preferably 0.4 to 0.6 moles per liter of sodium hydroxide. Sodium hydroxide is preferably selected as the (main) agent for obtaining the alkaline character of the aqueous composition. Other alkaline agents such as potassium hydroxide, ammonium hydroxide, lithium hydroxide, ammonium carbonate may also be considered, but sodium hydroxide is preferred because it is cheap and readily available. It has been found that the ratio by weight between sodium hydroxide and the alkyl polyglycoside is preferably between 4 : 1 and 6 : 1, most preferably around 5 : 1, for achieving an effective composition.

In another preferred embodiment, the alkyl polyglycoside in the aqueous composition has an alkyl chain with an average carbon chain length of from C₄ to Ci₄, preferably from C₆ to Ci₀, more preferably from C₇ to C₈.

It is preferred to have an alkyl polyglycoside with an average alkyl chain length of from (and including) C₄ to (and including) Ci₄. The use of alkyl polyglycosides with a lower average alkyl chain length of C₃ and lower will result in a much smaller distribution of the composition in the area treated. Alkyl polyglycosides with average alkyl chain lengths above C₄₄ are not preferred either, since these are expected to be less compatible with the aqueous character of the composition due to their relatively long alkyl chain length. Within this range, it is preferred to use alkyl polyglycosides with an average alkyl chain length from C₆ to Ci₀, since the longer chain lengths have a tendency to work as a foam inhibitor, more preferably from C₇ to C₈ since these are more readily available.

Possible examples of alkyl polyglycosides are e.g. glucopyranosides or maltopyranosides, such as n-heptyl b-D-glucopyranoside, n-octyl b-D-glucopyranoside, n-nonyl b-D- glucopyranoside, n-heptyl b-D-maltopyranoside, n-octyl b-D-maltopyranoside, n-nonyl b-D- maltopyranoside and similar, as well as combinations of at least two of these.

In another preferred embodiment, the method comprises the step of subsequently applying a further composition to said area, the further composition having a pH between 2.0 and 4.0, preferably around 3.0.

Despite its alkaline character, the aqueous composition according to the invention is expected to be accompanied by no or a limited amount of impairment to the environment, e.g. the tree on which it is applied. However, if such damage were to occur, or as a precautionary measure, it is or may preferred to apply a mild acidic composition after (e.g. within 1 minute, within 5 minutes or within 10 minutes after and, in each of these cases, preferably at least one sixth of this time after and/or at least 10 seconds after) the application of the aqueous alkaline composition, in order to neutralize the alkaline composition. The alkaline composition will work (nearly) instantly in order to treat or destruct the caterpillar. In contrast, the aqueous alkaline solution will require more time than that in order to be absorbed in the trunk of the tree. Therefore, the use of a mild acidic will be able to equalize the pH around the area sufficiently in order to avoid extensive damage to the tree, while still being able to reduce the inconveniences caused by the caterpillar. This composition may also be supplied in a more concentrated form.

Preferably, the further composition comprises a polyhydric acid. More preferably, the polyhydric acid is selected from phosphoric acid, citric acid and lactic acid. Due to the plurality of acid groups, the polyhydric acids are advantageous to quickly reduce the pH at a specific area.

Still, the polyhydric acids themselves are not highly acidic and therefore do not constitute any harm to the environment.

In another preferred embodiment, the aqueous composition further comprises a peroxide- based alkalineagent.

In the treatment of caterpillars with a relatively large thickness (i.e. their dimensions measured perpendicular to their longitudinal axis), such as a Thaumetopoea pityocampa caterpillar in comparison to a Thaumetopoea processionea caterpillar, it is conceived that a more effective treatment will be obtained when the composition comprises a peroxide-based alkaline agent.. The peroxide-based agent will penetrate the caterpillar. The application of the mild acidic composition to the caterpillar as the next step will cause effervescence by formation of carbon dioxide and/or disintegration of the caterpillar.

Preferably, the peroxide-based foaming agent is selected from perborate or percarbonate. Preferred examples are sodium percarbonate or potassium percarbonate.

In another preferred embodiment, the method further comprises the prior step of diluting the composition with water to its applied concentration with water. The composition used in the method according to the invention is preferably offered in a more concentrated (less diluted) form, preferably 5 to 10 times more concentrated than the concentrations in which these are to be applied to the area. The provision of the composition in such a more concentrated form allows the composition to be distributed more efficiently. Typically, the composition will be provided with instructions to dilute the composition to a suitable concentration before application. Therefore, the concentration of alkyl polyglycosides and the molarity of the alkaline component are, in the composition as provided, e.g. to users of the composition, typically higher than the concentrations according to the claims.

In another preferred embodiment, the composition is applied by nebulization.

While it is also possible to apply the composition by other means, it is preferred to apply the composition by nebulization, e.g. with an atomizer. Nebulization allows the composition to reach a relatively large area in a small amount of time, thereby increasing the efficacy of the composition. Thereby, nebulization decreases the probability of an unwanted escape by the caterpillar. In another preferred embodiment, the area comprises one or more caterpillars, such as caterpillars from the subfamily of Thaumetopoeinae, such as Thaumetopoea processionea or Thaumetopoea pityocampa, preferably including residual hairs thereof.

The composition is preferably applied onto the caterpillar, for its ability to treat and/or destruct the one or more caterpillars by protein coagulation and fat saponification. The caterpillars are preferably grouped as a nest in order to achieve a larger efficacy. Preferably, the definition of the caterpillars in this and depending embodiments also includes or alternatively comprises residual hairs, located in the remains from the caterpillar, e.g. after having pupated to a moth, as it has been shown that the composition is also able to bind the hairs, which thereby adhere to each other.

In another preferred embodiment, the area is located on a tree from the family of Fagaceae or Pinaceae, preferably the trunk of the tree.

The caterpillars from the subfamily primarily reside on trees ( Thaumetopoea processionea prefers trees from the family of Fagaceae, while Thaumetopoea pityocampa prefers trees from the family of Pinaceae). The inconveniences caused by these caterpillars are the most severe in these preferred areas, so it preferred to apply the composition onto these respective preferred areas. The composition is preferably applied to the trunk of the tree, since this is the area where the caterpillars mainly reside and the place on which they cause most inconvenience to other species.

The method may be carried out either by so-called drop treatment or by stick treatment (described hereafter). Drop treatment comprises the application of such an amount to the area which will cause harm and/or agglutination to such an extent that the caterpillar or nest of caterpillars will drop or detach from the tree. A person skilled in the art (the end-user) will, depending on the size of the area populated by the one or more caterpillars, and visual feedback when applying the composition, readily be able determine the amount of composition necessary in order to achieve a drop treatment.

In another preferred embodiment, the method further comprises the step of removing the caterpillar from the area by vacuum suction after the application of the aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside.

Stick treatment, which requires a smaller amount of composition than for drop treatment, also causes harm and/or agglutination to such an extent that the caterpillars will stick together, making it easier to remove the caterpillar from the tree with the known suction devices. Stick treatment may be preferred over drop treatment, especially in cases where it is preferred to use a limited amount of composition, or when detachment of the caterpillars from the tree into the wild is undesirable. In another preferred embodiment, the area onto which the composition is applied is an area which does not comprises one or more caterpillars and which is located on a tree from the family of Fagaceae or Pinaceae, preferably the trunk of the tree, more preferably close to the bottom of the trunk of the tree.

Apart from its ability to treat and/or destruct caterpillars, it has surprisingly been found that the application of the composition onto an area also serves as an effective preventive measure, thereby creating a barrier which the caterpillar is less likely to cross. Therefore, application of the composition on the trunk of the tree will significantly reduce the amount of caterpillars beyond this barrier, especially when the composition is applied around the full circumference of the trunk. The bottom of the trunk of the tree, which is close to the ground, therefore is the most effective for applying the composition in order to fulfill its barrier function.

It is furthermore observed that the composition used in the method according to the invention can also be used in an area located within a container, such as a refuse bag. Apart from the application on trees, it has also been discovered that the composition is able to bind caterpillars and/or (residual) hairs thereof in other circumstances, such as in the treatment of waste, thereby reducing uncontrolled distribution of hairs, which may cause problems in waste processing.

The object is further achieved with a kit-of-parts comprising:

- an aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside; and

- a composition having a pH between 2.0 and 4.0, preferably around 3.0.

The object is further achieved with an aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside and a peroxide- based alkaline agent. The alkyl polyglycoside in the aqueous composition preferably has an alkyl chain with an average carbon chain length of from C₄ to Ci₄, preferably from C₆ to Ci₀, more preferably from C₇ to C₈. One or more of the compositions may be offered in a more concentrated form.

The alkaline character of the composition causes protein coagulation and/or fat saponification when used against caterpillars. Alkyl polyglycosides improve the wetting properties of the alkaline aqueous composition and are more suitable than other surfactants, since these are able to tolerate an alkaline environment. This composition reduces the inconveniences caused by the caterpillar in a way as discussed in relation to the method according to the invention, and to which is referred to herewith. The following examples are provided to further illustrate the present invention and are not to be construed as limiting the invention in any manner. In the following examples, the compositions according to the invention were assessed in its efficacy in prevention and/or treatment and/or destruction, in comparison to both methods according to the prior art, and compositions lacking essential ingredients according to the invention. For sake of clarity it is observed that any of the embodiments discussed above and/or defined in the claims with respect to one aspect of the invention also apply to another aspect of the invention even if not indicated explicitly.

EXAMPLE 1

A first composition (based on tap water) of 1 L was prepared, consisting of 0.5 M sodium hydroxide, 20 grams of the composition of alkyl polyglycoside with average alkyl chain length of 7-8, and added up to 100 percent by weight with tap water. A second and third composition were prepared, equal to the first composition with the exception of sodium hydroxide or no alkyl polyglycoside in the second and third composition, respectively.

EXAMPLE 2

A number of trees from the species Quercus (oak) which were standing apart from each other were selected, populated with at least one nest of Thaumetopoea processionea with an approximately (as visually confirmed) equal coverage of the trunk of the tree. The first composition was applied to the nest on a first tree by a nebulization in an amount which caused the nest to detach from the tree. In the detached nest, the caterpillars were visually confirmed dead and adhered to each other to a large extent. This experiment was repeated with the second and third composition on a nearby second and third tree, with the application of the same amount of composition. With the second composition, the caterpillars were confirmed wetted but alive. With the third composition, dead caterpillars were observed among alive caterpillars within the nest, in an amount not sufficient to affect the integrity of the nest.

EXAMPLE 3

One of the trees selected in the previous experiment which was not treated, was treated with the first composition in an amount of 60% of the amount used in Example 2. The nest was confirmed to be wetted, and the caterpillars were partly dead, but in majority sticking to each other.

EXAMPLE 4

One of the trees selected in Example 2 which was not treated in a previous Example, was selected for treatment using suction equipment. The nest was removed from the tree by suction treatment by a person, wearing protective clothing except from around his left forearm. The removal of the nest from the tree took approximately 45 minutes. The tree from Example 3 was also cleaned by suction treatment in a similar way, 5 minutes after application of the composition, by the same person, wearing protective clothing, except from around his right forearm. The removal of the nest from this tree took approximately 5 minutes. In the days after the removal of the nests from the trees, large amounts of rash occurred concentrated on the left forearm of the person, confirming hair release in the suction treatment of the untreated tree.

EXAMPLE 5

Six neighboring other (i.e. not treated nor cleaned in the previous Examples) trees selected in Example 2 were cleaned by conventional means (suction treatment), and collected in refuse bags. These trees were divided in a first and second group, alternately arranged in a row. The first composition was only applied to the total circumference of the bottom of the trunk of the trees of the first group. The second group was apart from the suction treatment, left untreated. One month later, it was visually confirmed that the three trees from the first group were still free from caterpillars while each of the three trees from the second group had nests of caterpillar on the trunk.

EXAMPLE 6

The refuse bags from Example 5 were collected, and an amount of the first composition was added to three of the bags in an amount which was sufficient to wet the caterpillars within the bag comparable to the use according to Example 3. The bags were closed, vigorously shaken and left to stand. After one hour, the caterpillars in the bag were visually confirmed to stick to each other. In the other three bags, the same amount of a composition was added, consisting of 50% of the first composition and 50% tap water. The bags were also closed and vigorously shaken and left to stand. After both 1 and 3 hours, the caterpillars in these bags were visually confirmed to be mainly separate.

Claims

1. Method for reducing or obviating caterpillar plagues, comprising the step of applying an aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside to an area located on a tree.

2. Method according to claim 1, wherein the one or more caterpillars are from the subfamily of Thaumetopoeinae, such as Thaumetopoea processionea or Thaumetopoea pityocampa.

3. Method according to claim 1 or 2, wherein the aqueous composition comprises from 0.3 to 0.7, preferably 0.4 to 0.6 moles per liter of sodium hydroxide.

4. Method according to claim 1, 2 or 3, wherein the alkyl polyglycoside in the aqueous composition has an alkyl chain with an average carbon chain length of from C₄ to Ci₄, preferably from C₆ to Ci₀, more preferably from C₇ to C₈.

5. Method according to any of the preceding claims, comprising the step of subsequently applying a further composition to said area, the further composition having a pH between 2.0 and 4.0, preferably around 3.0.

6. Method according to claim 5, wherein the further composition comprises a polyhydric acid.

7. Method according to claim 6, wherein the polyhydric acid is selected from phosphoric acid, citric acid and lactic acid.

8. Method according to claim 5, 6 or 7, wherein the aqueous composition further comprises a peroxide-based alkaline agent.

9. Method according to claim 8, wherein the peroxide-based alkaline agent is selected from perborate or percarbonate.

10. Method according to any of the preceding claims, wherein the method further comprises the prior step of diluting the composition with water to its applied concentration with water.

11. Method according to any of the preceding claims, wherein the composition is applied by nebulization.

12. Method according to any of the preceding claims, wherein the area comprises one or more caterpillars, such as caterpillars from the subfamily of Thaumetopoeinae, such as Thaumetopoea processionea or Thaumetopoea pityocampa, preferably including residual hairs thereof.

13. Method according to claim 12, wherein the area is located on a tree from the family of Fagaceae or Pinaceae, preferably the trunk of the tree.

14. Method according to any of the claims 12 or 13, wherein the method further comprises the step of removing the caterpillar from the area by vacuum suction after the application of the aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside.

15. Method according to any of the claims 1 to 11, wherein the area onto which the composition is applied is an area which does not comprises one or more caterpillars and which is located on a tree from the family of Fagaceae or Pinaceae, preferably the trunk of the tree, more preferably close to the bottom of the trunk of the tree.

16. Kit-of-parts for the method according to any of the preceding claims, comprising: an aqueous composition with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside; and a composition having a pH between 2.0 and 4.0, preferably around 3.0.

17. Aqueous composition for the method according to any the claims 1 to 15 with a pH of 11.0 or more and comprising 0.1-5 percent by weight of the composition of alkyl polyglycoside and a peroxide-based alkaline agent.

18. Aqueous composition according to claim 17, wherein the alkyl polyglycoside in the aqueous composition has an alkyl chain with an average carbon chain length of from C₄ to C_M, preferably from C₆ to Ci₀, more preferably from C₇ to C₈.