WO1997021349A1

WO1997021349A1 - Method for destroying termitaria

Info

Publication number: WO1997021349A1
Application number: PCT/FR1996/001954
Authority: WO
Inventors: Jean-Luc Clement; Blandine Vauchot; Marie-Madeleine Serment
Original assignee: Centre National De La Recherche Scientifique (Cnrs); Centre Technique Du Bois Et De L'ameublement
Priority date: 1995-12-08
Filing date: 1996-12-06
Publication date: 1997-06-19
Also published as: AU1101197A; FR2742024A1; FR2742024B1

Abstract

A method for destroying termitaria, wherein a bait consisting of a carrier containing FlufenoxuronTM or active derivatives thereof is placed adjacent to a termitarium to destroy workers, nymphs, larvae and soldiers, whether or not they have come into direct contact with the bait. Said carrier comprises a termite-ingestible material and the FlufenoxuronTM is at a concentration of 10-1000 ppm on the carrier.

Description

METHOD OF DESTRUCTION OF DUMMY

The present invention relates to a process for destroying termite mounds as well as to products more particularly suitable for the implementation of this process. Although termites are essentially tropical insects well known by their construction of often complex and spectacular buildings (the termite mound), there are also some more discreet species, due to their construction always underground, in our more temperate regions. In France, in particular, 6 species of termites have been identified and, if the first damage caused by termites is reported to

Bordeaux in 1850, 54 French departments are currently affected, notably Charente-Maritime, Gironde, Landes and departments of the Mediterranean arc, more than 2,000 municipalities are infested and, for information, 13 districts out of 20 in Paris are in the process of colonization by these insects.

Of course, this progression is largely favored by human activity, trade, transport of materials, removals, district heating, which allows the survival of these insects in regions where the climate is, in natural conditions, too harsh for them.

In the United States, it is estimated that the annual cost of treatment, control and prevention of termites is almost $ 2 trillion. This shows the considerable economic impact of these insects.

If it is necessary to provide preventive treatments, in particular by treating soil and timber, it is equally important to provide curative treatments, given the already very significant development of these insects worldwide. The "key" problem, when the insects are already installed, is being able to remove the termite nest itself.

Indeed, the termite is a discreet, lucifuge insect, only detectable by tunnels, called "cords", which it builds to protect itself from light when it moves on materials too hard to be dug. Swarms in spring can also detect their presence. But, most often, the detection of termites is late and the damage caused is already very significant. In addition, in this case, it is often very difficult to gain access to the termite hill and to be certain of having destroyed it. Also, for the protection of constructions, the most commonly used method at present consists in creating at the base of constructions an insecticide chemical barrier in order to prevent the access of these insects to the superstructures.

For the establishment of these barriers, among the chemicals currently most used as an insecticide, mention should be made of organochlorines, organophosphorus compounds and synthetic pyrethroids. These products have a shock effect.

These products having varying degrees of toxic effects on the environment, a new method is being implemented: the so-called "bait" method. This method consists in using delay-effect products which, through the usual trophallaxis food exchanges in termites, are communicated to all the individuals in the colony with the aim of thus leading to its elimination.

Until now, it has never been possible to demonstrate the advantage of this route of administration.

In the context of the present invention, it has been possible to highlight the fact that by using a particular toxicant, having a significant "delay" effect, this could ensure the progressive poisoning of the whole termite hill by diffusion toxin inside the termite nest to individuals who have had no direct contact with the bait and its destruction.

The present invention relates to the use of a pesticide called Flufenoxuron as a toxic agent allowing the destruction of termite mounds. More particularly, the present invention relates to a termite nest destruction process, characterized in that baits containing Flufenoxuron or its derivatives are placed close to it.

Flufenoxuron is described, in particular, in patent EP 161,019 and its derivatives. Flufenoxuron, already used in arboriculture and viticulture, is one of the third generation insecticides. It is an insecticide that inhibits the formation of chitin during moulting in insects. However, it has proved particularly interesting on termites in which workers, in particular, molt until their death. Given its type of activity, its effect is slow and makes it possible to use it in bait technique.

As will be demonstrated in what follows, Flufenoxuron is effectively taken from the bait, then transmitted by trophallaxis, licking and / or contact to soldiers, larvae and neotenics and even to nymphs which are not fed by themselves.

It has thus been demonstrated that the baits spread near the termite hill, preferably within a radius of less than 200 m, more particularly less than 50 m, were taken by the workers and contaminated the whole termite hill leading to term, its destruction or, at the very least, a drastic reduction of it. This process is particularly interesting for contaminating nymphs.

The baits consist of a support for materials capable of being ingested by termites, that is to say in particular products based on cellulose or cellulose derivatives such as paper, wood or by-products. of the agricultural industry like corn cobs.

It is possible, in particular, to constitute baits of agglomerated wood with sawdust for example, which makes it possible to obtain any shapes. It is also possible to poison pieces of wood by deep impregnation, but it is less easy to control the concentration of the product.

These supports are preferably impregnated with Flufenoxuron, either from an aqueous phase, or from an organic phase containing in particular N-methylpyrolidone.

These supports impregnated with Flufenoxuron can be in different forms, in particular they can be agglomerated with products which are preferably non-toxic for the environment and inexpensive, in particular solid hydrophobic products such as paraffins for example. Elements are thus obtained in which the termites can dig and thus ingest the Flufenoxuron, the latter being also protected from the weather. It is also possible to provide other systems, in particular bait boxes, whose technology is well known, and which will not be recalled in detail.

This control mode is applicable to European termites of the genus Reticulitermes (santonensis, (lucifugus) grassei, (lucifugus) banyulensis, (lucifugus) corsicus, (lucifugus) lucifugus ...) as well as to American and Japanese termites of the genus Reticulitermes ( flavipes, virginicus, malletei, hageni, speratus ...), Heterotermes sp., Coptotermes including C. formosanus and Zootermopsis spp. As regards the concentrations of the impregnated supports, it is preferable to use concentrations of between

10 and 1000 ppm, preferably less than 500 ppm, preferably between 50 and 250 ppm, in general of the order of 80 to 150 ppm. Indeed, under these conditions the product has no repellent effect and nevertheless has the toxic properties which are sought.

Other characteristics and advantages of the present invention will appear on reading the examples below. EXAMPLE 1

Preliminary tests have determined the LD50 and LC50 of Flufenoxuron on termites.

The LD50 is the dose of product applied topically to an individual which results in a mortality equal to 50% among the individuals thus treated. LC50 is the concentration of the product on a support which causes

50% mortality among individuals ingesting this medium or in contact with this medium.

Different treatments have been tested: topical application, soil treatment, ingestion for different concentrations of the product and on two species of termite: Reticulitermes (1.) grassei and Reticulitermes santonensis. The determination of the LD50 and the LC50 made it possible to show that the mortalities obtained are always less than 50% for a period of soil treatment or by ingestion less than 9 days and for a period less than 10 days following a topical application of the product. No concentration below 500 ppm or dose below 500 ppm causes 50% mortality in individuals tested before 15 days. For lower doses, 10 to 30 ppm, mortalities of 50% are reached after 25 days. Flufenoxuron therefore has the characteristics required for the destruction of termite mounds, namely that termite workers, instead of dying immediately after ingestion of Flufenoxuron, will have time to contaminate the rest of the termite hill through trophallactic exchanges with others castes when this product is used as a soil treatment.

The products tested were either paper or corn cobs, which were impregnated with Flufenoxuron formulated either in aqueous base or in solvent base. The aqueous base formulation contains the active ingredient

Flufenoxuron, water and agents for improving the wetting of Flufenoxuron and its dispersion as well as dyes: alkoxylated alkylphenol, antifoam based on mineral oil, dipropylene glycol + water, heteropolysaccharide, propylene glycol, salt 1,2-benzisothiazoline-3-one sodium, the formulation of the solvent base is composed of Flufenoxuron and 3% of N-methylpyrolidone.

For the use of Flufenoxuron in bait technique, we also tested sticks of corn cobs but impregnated which were agglomerated with paraffin. EXAMPLE 2

SPREAD OF IIC MARKED FLUFENOXURON WHEN PART OF THE GROUP ONLY IS CONTAMINATED

As indicated above, in order to be able to destroy a termite hill it is important to highlight the fact that trophallaxic exchanges are going well, that is to say in particular that the larvae and nymphs can be contaminated, so that these cannot come directly into contact with the baits. Although this phenomenon has been suspected on numerous occasions, it has never been able to be highlighted. In the present case, a marked Flufenoxuron was used to demonstrate this phenomenon, it is l- (2,6-difluorobenzoyl) - 3- (2- f 1 uor o-4 - (2- chl or o-4-trif 1 uor ometh yl ph en oxy) [ring -U - ¹⁴ Cj phenyljurea.

This test consists in determining the propagation of the product within a group of termites, part of which has previously ingested Flufenoxuron labeled with i ^ C. 50 termites are first marked with a metal wire. This marking technique using metal belts has already been described: on Leptothorax ants, a metal wire is knotted at the joints of the petiole of the furnace. It is the first time that this technique has been applied to termites. Termites are very soft insects, so be careful not to crush them when handling. They do not have a petiole, which is why the metal wire (3/100 mm) is tied around the neck of individuals. To facilitate its installation, the termites are slightly asleep with carbon dioxide. 50 termites are thus marked with metal collars, visible to the naked eye, which do not hinder their movements or their movements.

From the 1st day, the 10 termites taken from the 500 termites without a collar are already contaminated: 220 cpm, or 2.4 ng, of Flufenoxuron marked by termite. In the first 10 days, values between 220 and 655 ± 207 cpm are obtained, ie between 1 and 2.8 ng of product per individual, with significant interindividual variations (confidence interval). After 10 days, the radioactivity per individual decreases, at the same time as the interindividual variations, and the quantities of Flufenoxuron per termite reach approximately 1 ng after 34 days. Note that the amounts of Flufenoxuron per individual have a sinusoidal curve, the amplitude of which decreases over time. At the same time, in the 50 individuals who had previously ingested iK-labeled Flufenoxuron, a progressive decrease in the amounts of Flufenoxuron per individual is observed. Flufenoxuron marked with ι ⁴ C passes very quickly from individuals already contaminated by the product to other individuals not contaminated to lethal doses during their moult, if the number of infected individuals is sufficient. EXAMPLE 3 CONTAMINATION OF THE DIFFERENT CATEGORIES OF TERMITES ACCORDING TO THE DOSES OF FLUFENOXURON USED

Workers represent the only category of termites to feed themselves. They must feed the other castes by trophallactic exchanges. We wanted to check whether the product propagated well throughout the termite mound, that is to say across all categories: nymphs, larvae, soldiers and neotenics. Three groups of 1,000 workers, 600 nymphs, 100 larvae, 50 soldiers and 20 neotenics, from the same colony, are each installed in a "Lab" box (18 x 24 x 4.5 cm). This contains, in one half, Fontainebleau sand regularly moistened to about 1 cm thick so that they can dig galleries, in the other half, a piece of filter paper impregnated with Flufenoxuron marked with 14C at 100 ppm for the first group, 250 ppm for the second group and 500 ppm for the third. This filter paper is the only food available to termites. The experience lasts 25 days. Radioactivity is counted on 10 workers at intervals of 1, 2 or 3 days. 5 nymphs, 5 larvae, 5 soldiers and 5 neotenics are also extracted and passed individually to the β counter, after 10 days, 17 days and 21 days. We could not carry out as many counts on these 4 categories as on the workers because we did not have enough of them in each of the groups. This is done for the 3 groups (100, 250 and 500 ppm).

To be able to compare the quantities of radioactivity measured for each category, we presented these quantities in mg of individual. A worker weighs on average 2.15 mg, a larva 0.7 mg, a nymph 2.6 mg, a soldier 3.5 mg and a neotenic 7.5 mg.

The results show that regardless of the concentration of Flufenoxuron ¹⁴ C in the filter paper, workers feed on paper and become contaminated. When individuals are fed paper impregnated with product at 250 and 500 ppm, the amounts of Flufenoxuron per mg of individual increase very rapidly up to 10 days for 250 ppm and up to 8 days for 500 ppm. For 250 ppm, the quantities of Flufenoxuron go from approximately 6.5 ng (1,500 ± 603 cpm) to approximately 32 ng (7,500 + 1,423 cpm) per mg of individual, in 10 days. For 500 ppm, the quantities of Flufenoxuron go from approximately 4 ng (952 ± 283 cpm) to approximately 40 ng (9,500 + 1,236 cpm) per mg of individual, in 8 days. The quantities of product per mg of individual then increase more slowly and pass, for 250 ppm, from approximately 32 ng (at 10 days) to 36 ng (8,400 + 1,642 cpm) (at 22 days). For 500 ppm, these quantities go from 40 ng (at 8 days) to 65 ng (. 1,470 + 2,366 cpm) (at 17 days), and drop suddenly after 17 days, to reach around 40 ng (9,353 ± 854 cpm) after 22 days. When individuals are fed with filter paper impregnated with the product at 100 ppm, the amounts of Flufenoxuron per mg termites increase much more regularly and more slowly; they go from around 2 ng (544 ± 166 cpm) after 1 day to around 14 ng (3320 ± 392 cpm) after 22 days.

We also note that whatever the concentration used, the other categories (nymphs, larvae, soldiers and neotenics) which do not feed alone are also contaminated, and more particularly nymphs. In the batch where the termites are fed with filter paper impregnated with product at 100 ppm, a nymph contains at 8 days approximately 6 ng (1,349 ± 789 cpm) of Flufenoxuron per mg, or 75% of the quantity contained in a worker per mg for the same period, and almost 8 ng (1 83 1 ± 732 cpm) at 19 days, or 53% of the quantity present in a worker. For the batch fed with paper impregnated with Flufenoxuron labeled with 14C at 250 ppm, a nymph contains 13 ng (2,944 ± 1,404 cpm) of product per mg after 8 days, or 75% of what a worker contains per mg, and 19 ng (4,426 ± 2,202) after 19 days, or 55% of what a worker contains after this same period. For the 500 ppm concentration, a nymph contains, after 8 days, 18 ng (4,191 ± 2,030 cpm) of Flufenoxuron per mg, or 44% of what a worker has per mg, and approximately 33 ng (7,564 ± 1 188 cpm), after 19 days, i.e. 65% of the quantity present in a worker per mg. For the batch where the paper is treated at 100 ppm, the quantities of product contained in the 3 categories, soldiers, larvae and neotenics, follow roughly the same curve and go respectively from 13%, 13% and 7.76% of the quantities present in a worker per mg after 10 days, at 12%, 28.5% and 24.5% after 19 days. This corresponds in nanograms to 1 ng, 1 ng and 0.5 ng per mg at 8 days and 1 ng, 4 ng and 3 ng after 1 9 days.

For the batch where the termites have paper treated at 250 ppm, the 3 categories, soldiers, larvae and neotenics, respectively represent 1 1, 7%, 55.7% and 43% of the quantities of Flufenoxuron contained in a worker per mg after 8 days, and 12%, 0.8% and 0.55% of the amounts present in a worker per mg after 19 days. This corresponds in nanograms to 2 ng, 9 ng and 7 ng per mg after 8 days, and 3 ng of Flufenoxuron per mg for soldiers, and almost zero amounts for larvae and neotenics after 19 days.

The 3 categories, soldiers, larvae and neotenics, of the batch having paper impregnated with product at 500 ppm present quantities not exceeding 8.5 ng per mg: 10.4%, 0.22% and 0.15% of the quantities of Flufenoxuron contained in one worker per mg after 8 days and 17%, 5.5% and 0.61% of that in one worker per mg after 19 days. The amount of paper ingested during the experiment in the batch where the concentration tested is 100 ppm is 1,220 mg, i.e. 0.12 μg of Flufenoxuron labeled with t ⁴ C. 800 mg of paper were ingested by the individuals in the batch with paper treated at 250 ppm, i.e. 0.2 μg of labeled Flufenoxuron. 700 mg of paper impregnated with Flufenoxuron at 500 ppm were ingested by individuals, ie 0.35 μg of labeled Flufenoxuron. We therefore notice that the more the paper is impregnated in high concentration, the less the workers ingest it, but the more they are contaminated. The worker termites ingest the Flufenoxuron whatever the concentration and transmit it to the other categories, soldiers, larvae, nymphs and neotenics, who do not feed by themselves. We note however that the category of nymphs is the most contaminated. EXAMPLE 4

In these experiments we wanted to highlight the importance of the concentration of Flufenoxuron on the impregnated paper, in particular when the insects are in the position of choice, that is to say when they have a non-control paper. treaty.

The results show that, in a situation of choice, workers are contaminated about 2.5 times less than when they only have treated paper. Thus, in the batch where the concentration used is 100 ppm, individuals contain a maximum of 14 ng per mg of product after 22 days in a situation of non-choice and a maximum of 13 ng per individual at 19 days in a situation of choice. For the batch where the concentration used is 250 ppm, the individuals contain a maximum of 36 ng per mg after 22 days in a situation of no choice and a maximum of 30 ng per individual after 9 days in a situation of choice.

In batches with paper treated at 500 ppm, individuals avoid contaminated paper, so at this concentration there is already a repellent effect. Tests carried out in comparison with termites fed on paper treated with Flufenoxuron and on cobs of corn treated with Flufenoxuron have shown that consumption is comparable.

Similarly, additional tests have shown that the quantities of Flufenoxuron measured on an entire individual correspond, for more than 90%, to internal Flufenoxuron absorbed by ingestion. EXAMPLE 5

LAND TREATMENT IN BAIT TECHNIQUE

The selected site was an old landfill filled in for 5 years located in an area deemed to be unterminated. The presence of termites was recently detected there. These insects, most certainly present for several years, were brought there, either by infested waste before the landfill closed, or by infested embankments when it was closed.

The application of toxic chemicals on the surface of the land, the only method that has been used until now, in addition to the risks to the environment, would have only allowed the temporary reduction in the number of termites.

This infested area appears at first sight limited and the owner of the premises wanting a total elimination of these undesirable, it seemed interesting to set up the "bait" method. termites are identified as Reticulitermes san ton en sis. This land is a playground which has the advantage of having no construction and little source of wood for termites, termites must therefore feed on the waste from the old landfill contained in the ground.

At the start of the experiment, 49 fir wooden stakes which had not undergone any chemical treatment were placed every 6 meters around the experimental site in order to locate the various sources of infestation and in order to attract termites in precise places towards the stakes which constitute as many sources of food. Indeed, we know that termites build galleries to their food and that they always borrow the same. The termites must therefore return to where the stakes were planted when they are replaced.

The first survey of the stakes and the implementation of the treatment takes place on October 7, 1994, only the attacked stakes are replaced by bait boxes (12 x 8 x 4.5 cm) with 20 small holes (2 mm in diameter on 4 vertical sides) and containing corn cob impregnated with paraffin and Flufenoxuron at 125 ppm. Termites recovered from the attacked stakes are placed in each box so that they begin to dig galleries and recruit the others. During this first survey, it was found that 27 of the 49 stakes were very heavily attacked. We were thus able to establish, from the weighing of the stakes, the quantity of wood consumed per week and per month by the termites on all the stakes planted, it is this consumption of wood which will be monitored on each survey and which will provide information on termite activity and therefore their presence.

For the period from June 17 to October 7, the consumption of termite wood on all the stakes is 343 g per month; an untreated control stake is then placed approximately 1 m from each box, the stakes which are not attacked during the first survey are left in place and also serve as controls. All the stakes are checked every 1 to 2 months, those that are attacked are weighed to know the consumption of termite wood and consequently their activity over the duration of the treatment.

A second statement one month after the application of the treatment is carried out on November 8 and the third on December 7. At each operation, the inside of the boxes is checked, the dead termites found are removed, there is no need to add stalks to the boxes, these having disappeared very little. The attacked stakes are replaced by other stakes and are weighed in the laboratory after a week spent in an oven at 50 ° C.

A fourth survey was carried out on February 9, 1995. Some boxes now contain very few stalks, so it was necessary to add more.

During the second survey, we were able to highlight the fact that the termites had consumed on all the stakes only 31 g per month, that is to say about 10 times less than for the previous period. Only 4 stakes were attacked between the two surveys, including 2 weakly. The contents of each box filled with treated stalks were checked, the stalks disappeared little, no living termite was found inside the boxes. The presence of soil and galleries inside the boxes makes it possible to say that the termites circulated there.

During the third survey, the consumption of wood is 63 g per month, that is to say approximately 5 times less than before treatment and 2 times more than the previous month.

During the fourth survey, 4 months after the application of the treatment, only 4 of the stakes were attacked, 1 of which was very slightly and the consumption was 16 g per month, that is to say approximately 20 times less than before the treatment. The results of this field treatment in bait technique show that the consumption of termite wood decreases during the 4 months following the treatment in a very significant way. EXAMPLE 6 STUDY OF IA MORTALITY ON OTHER SPECIES OF TERMITES

Mortality by ingestion of filter papers impregnated with different doses of Flufenoxuron was studied under the same conditions as above. The results are as follows:

Reticulitermes speratus (Japanese species) on 100 termites

Heterotermes indicola (American species) average in percentage

There is a control with quantities of 250 ppm for the Japanese species, beyond and up to 1000 ppm there is a decrease in activity.

On the other hand, for the American species, doses of the order of 1000 ppm are necessary to observe insect control.

Claims

1) Termite nest destruction process, characterized in that it is placed near the termite nest, in order to destroy the workers, the nymphs, the larvae and the soldiers, whether or not they have had direct contact with the bait, a bait consisting of a support containing Flufenoxuron or its active derivatives, the support comprising a material ingestible by termites and Flufenoxuron being at a concentration on the support of between 10 and 1000 ppm.

2) Method according to claim 1, characterized in that destroys the nymphs.

3) Method according to claim 1, characterized in that the material ingestible by termites consists of cellulose or cellulose derivatives.

4) Method according to claim 3, characterized in that the cellulose-containing material is paper or agricultural cellulosic by-products.

5) Method according to claim 4, characterized in that it is corn cobs.

6) Method according to one of claims 1 to 5, characterized in that the baits are obtained by impregnating the support with

Flufenoxuron or its derivatives.

7) Method according to claim 6, characterized in that the impregnation is carried out from Flufenoxuron in the aqueous phase.

8) Method according to claim 6, characterized in that the baits are obtained by impregnating Flufenoxuron in solvent phase.

9) Method according to claim 8, characterized in that the solvent comprises N-methylpyrolidone.

10) Method according to claim 9, characterized in that the concentration is less than 500 ppm. 1 1) Method according to claim 9, characterized in that the concentration is between 50 and 250 ppm.

12) Method according to claim 9, characterized in that the concentration is between 80 and 150 ppm.

13) Method according to one of claims 1 to 12, characterized in that the baits are obtained by agglomeration of cellulose with a solid hydrophobic derivative. 14) Method according to claim 13, characterized in that the solid hydrophobic derivative is paraffin.

15) Method according to one of claims 1 to 12, characterized in that the baits are placed in bait boxes.