WO1992002138A1

WO1992002138A1 - Oviposition-preventing pheromone containing at least one fatty acid alkyl ester, and uses thereof for controlling crop-destroying insects

Info

Publication number: WO1992002138A1
Application number: PCT/FR1991/000641
Authority: WO
Inventors: Denis Thiery
Original assignee: Centre National De La Recherche Scientifique (Cnrs); Institut National De La Recherche Agronomique (Inra)
Priority date: 1990-08-10
Filing date: 1991-08-02
Publication date: 1992-02-20
Also published as: EP0495955A1; FR2665610A1; CA2066589A1; JPH05502045A; IL99105A0; FR2665610B1

Abstract

An oviposition-preventing pheremone preparation obtainable from a methanol extract of European corn borer eggs, and including a mixture of methyl esters of palmitoleic acid, palmitic acid, linoleic acid, oleic acid and stearic acid, an oviposition-preventing composition, designed particularly for countering the European corn borer, and including, as the active principle, at least one C1-3 alkyl ester of a C14-20 fatty acid, and use in controlling crop-destroying insects are described.

Description

ANTI-OVIPOSITION PHEROMONE COMPRISING AT LEAST ONE FATTY ACID ALKYL ESTER, AND ITS APPLICATION TO THE CONTROL OF PEST INSECTS.

The invention relates to the purification and characterization of an anti-oviposition pheromone, as well as to a chemical composition having the anti-oviposition properties of said pheromone, and to the application of said pheromone and said compound. ¬ the fight against insect pests. Anti-oviposition pheromones are intra-specific chemical signals deposited by certain female insects on and / or in the vicinity of their eggs after laying. The locations thus marked are then rejected by the other females of the same species as nesting sites.

It has therefore been proposed to use the deterrent effect of these pheromones in the fight against insect pests.

However, although the existence of such pheromones has been described in many insects for review, see the publication by ROITBERG and PROKOPY, 1

[Bioscience, 2 _L L, 400-406 (1987)], very few have been able to be effectively purified, and their chemical nature remains most often undetermined. Currently, only two compounds of this type have been able to be chemically characterized; it is the kairo one of the lepidoptera Ephestia kuelmiella, which consists of a mixture of 16 triketones [MUDD, J. chem. plowshare Perkin trans., 1 2357-2362 (1983)], which is moreover not strictly speaking an anti-oviposition pheromone, but a kairomone present in the mandibular glands of the larva of this lepidopteran, and which exerts an effect attractive on its parasite, V-turia canescens. The other is the anti-oviposition pheromone of the dipteran Rhagoletis cerasi, which is a derivative of palmityl glucopyranoside; the synthesis of the four possible stereoisomers of this derivative has been carried out [ERNST and WAGNER, Helv. Chim. Acta, 22, 165-171, (1989)], in order to determine

REPLACEMENT SHEET ner which corresponded to the active natural form of the pheromone.

Previously, it had been shown that a partially purified preparation of this pheromone obtained from the secretions collected at the laying sites, reduced by 90% the infestation of the plants by R. cerasi [KATSOYAIflNOS and BOLLER, Z. Angex. Entomol., £ 2, 278-281 (1980)].

The existence and efficacy of anti-oviposition pheromones has also been demonstrated in other insects, but their chemical composition has not been determined. For example, KLIJNSTRA [Entomol. exp.appl., &, 139-146, (1986)] showed that an ethanolic solution obtained by washing Pieris brassicae eggs significantly reduced the laying of females of this species on plants treated with said solution.

It clearly appears that, whatever the potential interest of anti-oviposition pheromones in the fight against insect pests, their effective application can only be envisaged if it is possible to synthesize them chemically, in order to obtain them. in sufficient quantity.

Among the insect pests, one of those which is currently causing significant damage, resulting in significant economic losses, is the European corn borer, (Ostrinia nu ilalis). It is a noc¬ turne butterfly, which sticks its eggs in the form of plates (ooplaques) on the surface of leaves of different plants, then covers them with mucus. This lepidoptera is a pest of maize in which it causes significant decreases in harvests, which can reach 40% in some particularly susceptible hybrids [KLENKE et al., Crop science, 2, P-. 859 (1986)]. In addition, the damage caused by this insect is now spreading to other crops, such as vegetables and the cotton.

The means of control currently recommended against this insect use pesticides, essentially synthetic pyrethroids. However, these pyrethrinoids are increasingly suspected of promoting the spread of aphid populations, and of diseases, in particular viral, inoculated by sucking biting insects.

The existence of anti-oviposition substances in extracts of droppings of European corn borer larvae has been shown [DITTRICK et al., J. Insect. Physiol., 29. p 119 (1983)] but their chemical composition has not been determined; it was simply suggested that they were polar substances. In addition, the real biological role played by these substances can be questioned, insofar as the .., excrement of larvae are rarely present on the nesting sites of the corn borer. As it had previously been shown that substances of plant origin originating from injuries to plants, had anti-oviposition activity, DITTRICK et al. hypothesized that the anti-oviposition activity observed could be due to a substance originating from the plant, released into the excrement of the larvae. Up to now, the existence of an anti-oviposition pheromone associated with the laying of the European corn borer had not been demonstrated.

The Inventor is the first to extract such a substance from the eggs of the corn borer. Analysis of the extract thus obtained revealed that it was a complex mixture, as shown by the chromatographies of Figures 1 and 2.

The inventor has also managed to select and identify in this mixture, constituents which, surprisingly, have a anti-oviposition activity comparable to that of the total extract.

The present invention relates to a prepa¬ ration of anti-oviposition pheromone, which preparation is characterized in that it is suscep¬ tible to be obtained from a methanolic extract of the eggs of the corn borer, and in what it includes a mixture of the methyl esters of palmitoleic, palmitic, linoleic, oleic and stearic acids. According to a preferred embodiment of the present invention, said preparation comprises: between 10 and 20 parts of methyl palmitoleate, between 10 and 20 parts of methyl palmitate, between 10 and 20 parts of methyl linoleate, between 10 and 20 parts methyl oleate, for 1 to 2 parts of methyl stearate.

The identification of active components has enabled the formulation of simple compositions reproducing the effect, on the reduction of the laying of the corn borer, of the preparation of anti-oviposition pheromone in accordance with the invention.

The present invention further relates to an anti-oviposition composition, active in particular on the corn borer, and characterized in that it comprises as active ingredient, at least one alkyl ester in

and C-j_4_20 fatty acid *

According to a preferred embodiment of an anti-oviposition composition in accordance with the invention, it comprises, as active principle, at least one methyl ester of a fatty acid with a straight chain C- _j ^^ g-

According to a particularly advantageous arrangement of this embodiment, said methyl ester of fatty acid with a straight chain is chosen from the group which comprises: methyl palmitoleate, methyl palmitate, methyl linoleate, oleate of methyl, methyl stearate, and mixtures thereof. According to a preferred form of this arrangement, an anti-oviposition composition in accordance with the invention comprises: between 10 and 20 parts of methyl palmitoleate, between 10 and 20 parts of methyl palmitate, between 10 and 20 parts of methyl linoleate, between 10 and 20 parts of methyl oleate, for 1 to 2 parts of methyl stearate.

According to another preferred form of this arrangement, said composition comprises at least 0.08 g / l of methyl palmitoleate, 0.1 g / l of π-methyl palmitate, 0.08 g / l of methyl linoleate, 0 , lg / l of methyl oleate, 0.008 g / 1 of methyl stearate

These values represent the concentrations of active principles from which anti-oviposition activity has been observed. Of course, the methyl ester concentrations of fatty acids can be higher; the ir imale concentrations which can be used are only limited by the solubility of the active ingredients in the solvent used. Optimal concentrations vary depending on the treatment conditions in the field, number and frequency of applications, treatment of all plants or part of them, etc.

Advantageously, a composition in accordance with the invention comprises: between 0.3 and 2 g / 1 of methyl palmitoleate, between 0.3 and 2 g / 1 of methyl palmitate, between 0.3 and 2 g / 1 of methyl linoleate, between 0.3 and 2 g / 1 of methyl oleate and between 0.03 and 0.2 g / 1 of methyl stearate. As an example, an anti-oviposition composition comprising 1.1 g / l of methyl palmitoleate, 1.45 g / l of methyl palmitate, 1.1 g / l of methyl linoleate, 1.3 g / 1 methyl oleate and 0.1 g / 1 methyl stearate, dissolved in a mixture comprising 1 volume of methanol for 9 volumes of water, can be used for the treatment of corn plants under the following conditions: - single application - spraying of the composition on one row of corn on two.

Under these conditions, one liter of this solution is used to treat about 50 irr of crops. Anti-oviposition compositions in accordance with

1'Invention can be obtained in a simple and inexpensive, from alkyl esters of fatty acids which are readily available commercially. They can therefore be used on a large scale in the treatment of crops.

The present invention therefore also relates to the application of a composition, or a purified preparation of an anti-oviposition pheromone, as defined above, to the protection of plants against insect pests, particularly European moth. But.

In particular, the subject of the present invention is a process for protecting plants against insect pests, particularly the European corn borer, which process is characterized in that the plants to be treated are brought into contact with a composition or a preparation of pheromone. anti-oviposition according to the invention.

The present invention will be better understood with the aid of the additional description which follows, which refers to examples of preparation and use of the compositions in accordance with the invention. It goes without saying, however, that these examples are given solely by way of illustration of the subject of the invention of which they do not in any way constitute a limitation. EXAMPLE 1 OBTAINING A PHEROMONE PREPARATION

ANTI-OVIPOSITION FROM BRIDGES OF PYRALE DU MAIS

Females of Ostrinia nubilalis are induced to lay on a chemically inert substrate (glass plates rinsed with methanol). 1,580 plates were obtained in this way. The blades carrying the ooplaques were soaked for 12 hours in 200 ml of cold methanol (purity>^'99.9%). The extract obtained was then concentrated by evaporation, on a Dufton column, to a volume of 20 ml.

The different concentrations used subsequently are obtained by diluting the extract thus concentrated. EXAMPLE 2 - CHEMICAL CHARACTERIZATION OF THE PREPARATION

PURIFYING ANTI-OVIPOSITION PHEROMONE CONFORMING TO THE INVENTION

10 μl of the extract obtained in Example 1 are used for each analysis. 1 / gas chromatography

The characteristics of the apparatus used are as follows: injector on column, capillary column, phases DB5 id 0.53 (equiv. SE52) and CPWAX58 id 0.32 (equiv. Carbowax) (id = internal diameter). - The initial temperature is increased linearly from 70 ^* C to 240 ^* C.

The chromatography profiles obtained under these conditions are shown in Figures 1 and 2.

FIG. 1 represents the profile obtained on a CPWAX58 column. FIG. 2 represents the profile obtained on a DB5 column.

The compounds thus identified by each of these methods were compared, on the basis of their retention time, to standards. The dosage of the constituents was obtained by gas chromatography. The selected components were identified by infrared spectrometry, coupled with FOURIER transform analysis

Table I below gives the list of these components as well as the quantities dosed and the chemical characteristics.

TABLE I.

* Measured in μg / ooplate equivalent (average obtained from 1580 ooplates)

EXAMPLE 3 - PREPARATION OF A COMPOSITION

ANTI-OVIPOSITION IN ACCORDANCE WITH THE INVENTION

Methyl palmitoleate, methyl palmitate, methyl linoleate, methyl oleate, and methyl stearate (SIGMA) are mixed in the proportions indicated in Table I above. The mixture is dissolved in methanol EXAMPLE 4 - COMPARISON OF THE EFFICIENCY OF THE COMPOSITIONS

AflTl-QVlPQgmQN AND S fcft PfigPARAτiQN OF ANTI-OVIPOSITION HORMONE, IN ACCORDANCE WITH THE INVENTION, ON THE REDUCTION OF THE PYRALE OF THE MAIZE

The study of the laying behavior was carried out in altuglass cages in which an oviposition substrate allowing the laying was deposited, constituted by a plastic grid on which a sheet of waxed paper is deposited.

Each oviposition substrate has been divided into two zones: one is impregnated with the test solution (egg extract prepared according to the procedure described in Example 1, composition prepared according to the procedure described in Example 3, or solvent alone) at the desired concentration, the other is not impregnated.

For each solution tested, the deposit is made using a precision syringe. 90 drops of 2.5 μl each are deposited on the test area.

In the case of the extract, the concentrations used are expressed in opaque / drop equivalent, and are 0.7, 2, and 4. The anti-oviposition composition prepared according to the procedure described in Example 3 is used at a concentration of 1.616 g / ml of the mixture of methyl esters of fatty acids, which corresponds to 4 opaque equivalents / drop. After evaporation of the solvent, the treated oviposition supports were placed in the cages. 2-day-old borer females were left in the presence of supports, for 2 consecutive nights, at the end of which the ooplaques deposited on the treated areas, on the one hand, and on the untreated control areas, d on the other hand, were enumerated.

The results obtained which represent the average of 3 experiments are illustrated by FIGS. 3 and 4. FIG. 3 represents the results obtained with the preparation of egg extract: on the ordinate, the number of opoplates deposited on the treated area ( as a% of the total number of opoplates deposited on the support), and, on the abscissa, the concentration of the extract in ooplate equivalents / drop.

These results show that the number of opaque plates deposited on the treated area decreases very significantly when the concentration of the preparation deposited on the support increases. Figure 4 shows the comparison of the effectiveness of the preparation of egg extract of and the composition prepared as described in Example 3, on the reduction of the laying of the corn borer.

On the ordinate axis is the reduction of the% of opoids on the treated area compared to the untreated area. This clearly shows that the effectiveness of the anti-oviposition composition obtained in accordance with Example 3 is of the same order as that of the anti-oviposition pheromone preparation obtained from the eggs of borer.

As is apparent from the above, the invention is in no way limited to those of its modes of implementation, embodiment and application which have just been described more explicitly; on the contrary, it embraces all the variants which may come to mind of the technician in the matter, without departing from the scope or the scope of the present invention.

Claims

1) Preparation of anti-oviposition pheromone, which preparation is characterized in that it is capable of being obtained from a methanolic extract of the eggs of the European corn borer, and in that it comprises a mixture of the esters methyl of palmitoleic, palmitic, linoleic, oleic and stearic acids.

2) Preparation of anti-oviposition pheromone according to claim 1, which preparation is characterized in that it comprises: between 10 and 20 parts of methyl palmitoleate, between 10 and 20 parts of methyl palmitate, between 10 and 20 parts of methyl linoleate, between 10 and 20 parts of methyl oleate, for 1 to 2 parts of methyl stearate.

3) Anti-oviposition composition, active in particular on the corn borer, and characterized in that it comprises, as active principle, at least one C ^ _3 alkyl ester and C 1 fatty acid _| _ _2o- 4) Anti-oviposition composition according to claim 3, characterized in that it comprises, as active principle, at least one methyl ester of a fatty acid with a straight chain in

5) anti-oviposition composition according to claim 4, characterized in that it comprises at least one fatty acid methyl ester with a straight chain chosen from the group which comprises: methyl palmitoleate, methyl palmitate, linoleate methyl, methyl oleate, methyl stearate, and mixtures thereof.

6) Anti-oviposition composition according to Claim 5, characterized in that it comprises: between 10 and 20 parts of methyl palmitoleate, between 10 and 20 parts of methyl palmitate, between 10 and 20 parts of methyl linoleate, between 10 and 20 parts of methyl oleate, for 1 to 2 parts of methyl stearate.

7) anti-oviposition composition according to any one of claims 5 or 6, characterized in that it comprises at least 0.08 g / 1 of methyl palmitoleate, 0.1 g / 1 of methyl palmitate, 0, 08 g / 1 methyl linoleate, 0.1 g / 1 methyl oleate, 0.008 g / 1 methyl stearate 8) Anti-oviposition composition according to the

Claim 7, characterized in that it comprises: between 0.3 and 2 g / 1 of methyl palmitoleate, between 0.3 and 2 g / 1 of methyl palmitate, between 0.3 and 2 g / l of linoleate of methyl, between 0.3 and 2 g / 1 of methyl oleate and between 0.03 and 0.2 g / 1 of methyl stearate.

9) Application of an anti-oviposition pheromone composition or preparation according to any one of Claims 1 to 8 to the protection of plants against insect pests, particularly the European corn borer.

10) Process for protecting plants against insect pests, particularly the European corn borer, which process is characterized in that the plants to be treated are brought into contact with an anti-oviposition pheromone composition or preparation according to one any of Claims 1 to 8.