DE1139691B - Method for combating animal pests - Google Patents

Description

Methods for controlling animal pests The invention relates to a method for controlling animal pests, preferably insects, under Use of organic tin compounds.

It has been found that in the control of animal pests im Compared to the known pesticides, even better results Can be achieved using organic tin compounds of the general formula R, SnHal, in which R is a methyl or ethyl group and Hal is chlorine or bromine means, according to the invention, one or more of these active ingredients at room temperature can act in the gas phase on the pests.

The use of organic tin compounds as pesticides is known. However, it has always been used in liquid or solid form so far Shape, d. H. by impregnating, painting, spraying, spraying, etc. The tin compound essentially acted as a contact poison.

The disadvantage of this previous application is, among other things, that the agent has a permanent effect. This permanent effect is in individual cases, z. B. in moth control by impregnation, desirable, but in general undesirable, because the effectiveness decreases in the course of time, for example according to an exponential function, after. From a certain point in time, there is only such toxicity which is no longer sufficient to kill pests, but experience has shown that it is sufficient to To cause resistance phenomena.

On the other hand, for the rapid killing of pests, e.g. B. insects, already proposed organic tin compounds, but also in liquid form, be it together with a solvent or even with a breath poison.

Certain organic tin compounds have also become general ones Formula R4 Sn, however with four organic radicals on the tin atom, proposed, which - representing oily liquids at ordinary temperature - again im essential to act as contact poisons. But these were also called breath poisons investigated, but their effect compared to comparable substances is quite considerable was lower, even if the pests were in close proximity to the substances found.

It has now been found that it is among the organic tin compounds there are also those that have a high vapor pressure even at room temperature and therefore they are so volatile that they are in the gas phase under normal conditions can be applied. They gas within a limited period of time, e.g. B. one hour, completely. Any aftereffects can be gassed by ventilating the Completely eliminate space. In addition, the gassing can have a long-range effect Achieve, as a result of which hidden pests are destroyed. not Finally, the gasification involves much smaller amounts of the pesticide than in the known applications in liquid form.

Surprisingly, it has been shown that the organic Tin compounds in the gas phase have an extremely strong poisonous effect, which is one of the most effective gaseous pesticides known, like methyl bromide and hydrocyanic acid, by several powers of ten.

With a normal duration of the fumigation process, i.e. a maximum of 24 to 48 Hours, so great a gas concentration is generated that all of them controlled pests can be destroyed. The concentration required of the gas depends in each individual case on the toxicity (effectiveness) of the used Connection off. It turned out that among the substances with the above specified general formula such exist that have both a great volatility as well have a great toxicity, so that the fumigation process in a relatively short time and / or performed with relatively small amounts of the pesticide with the effect of the well-known "knock down" effect. Possibly According to the invention, methyl bromide can be added as a further insecticide. Methyl bromide is a good solvent, does not burn and disappears without a trace. Trimethyltin bromide and chloride, their vapor pressure values and Effectiveness values they appear particularly suitable for the present method permit.

The substances according to the invention do not need to be used purely come. For example, you can also work with other alkyl tin halides and others be mixed with volatile solvents.

Another option is to use a mixture, which essentially consists of one or more substances of the general formula (component 1) and one or more substances with such a vapor pressure (component 1I), that the total vapor pressure of the mixture is its application in the gas phase at room temperature permitted. According to this, if necessary, the compositions, inter alia according to the prevailing working conditions (temperature, air pressure, Humidity, etc.). In particular, component II can have a higher partial vapor pressure have as component I, thereby increasing the volatility of the mixture can. The above-mentioned insecticide methyl bromide is preferably used as component II in question. It is particularly advantageous if a substance is used as component II that was used to manufacture component 1. One can in this case in the production of component 1, the substance according to component 1I in excess add and then immediately receive the pesticide ready to use, without having to intervene further work steps beforehand.

The following measurements of the so-called gram-hour value (gst), which were carried out on various pests on the one hand with methyl bromide and hydrogen cyanide and on the other hand with the substances to be used according to the invention, provide information about the greater effects of the new method in controlling pests. The investigations were carried out in a glass case with a capacity of 2 m3. In this, the respective test animals were in permeable Plexiglas cells. The pesticide was put on filter paper in the chamber and gasified from there. The gases or vapors created in this way were circulated by means of a fan installed in the chamber. The animals were checked 24 hours after the plexiglass cells had been removed from the chamber. As usual, the product of the concentration in g / m 3 and the time in hours at which a 100% death is effected within 24 hours after the end of the fumigation is designated as the gst value. The test temperature was 20 ° C. in each case: depending on the type of pest, between 20 and 50 test animals were placed in each cell. Pesticide pest gst value concentration g / ma 1. Trimethyltin bromide grain beetle imagines 0.01 0.5 American Rice flour beetle 0.5 2. Trimethyl tin chloride a) Imagines 0.04 b) larvae 0.04 Wheat beetle adults 0.01 0.5 Wheat beetle adults 0.06 American 3. Triethyltin bromide flour beetle a) adults 0.12 b) larvae 0.2 Wheat beetle adults 0.03 0.5 American 4. Triethyltin chloride rice flour beetle a) adults 0.04 b) larvae 0.25 5. Mixture of methyl tin bromides and methyl grain beetle imagines 5 5 bromide made from 24 parts by weight methyl American bromide, 6 parts by weight of methanol and 1 weight of rice flour beetle, part tin adults 7.5 5 Wheat beetle adults 1 5 American 6. Mixture of methyl tin bromides and methyl flour beetle, bromide, made from 20 parts by weight of methyl imagines 2 5 bromide, 5 parts by weight of methanol and 1 weight of grain weevil imagines 0.5 0.5 part tin American Flour beetle, Adults 1 0.5 (Continuation) Pesticide pest gst value concentration glms Wheat beetle adults 0.17 1 7. Mixture of methyl tin bromides, made as American in experiment 6, where the excess methyl flour beetle, bromide was evaporated. Adults 0.35 Flour moth, caterpillars 0.35 For comparison Wheat beetle adults 60 10 B. Methyl bromide American Flour beetle, Adults 85 9. Hydrocyanic acid grain beetle adults 110 5 In experiments 5 to 7, mixtures were used which can be obtained by simply mixing methyl bromide, methanol and tin, the reaction being completed within a few weeks under normal temperature and normal pressure, while it is completed within a few weeks with an increase in pressure and a slightly increased temperature 2 days can be finished.

Similar implementations can be carried out in an analogous way with others Produce starting materials, especially using other alkyl halides and alcohols, especially primary alcohols, as starting materials.

In a test with mites, the test arrangement (Glyciphagus destructor) identical to the one described above.

The mites developed in a heavily populated grain beetle culture. Some dust with all stages of development of the mites was brought into the plug-in cells. The observation took place later in vessels, the bottom of which formed a glass frit and which were tightly closed with a glass lid. The killing of the mites (no movement in the vessel) could be observed well under the binocular. The following gst values were determined: trimethyltin chloride (concentration 0.5 g / m3). .. 0.5 trimethyltin bromide (concentration 0.5 g / m3) ... 1.0 In a test with snails (garden slugs), the experimental setup was again the same as for the tests with grain beetles and mites.

The snails collected in the Frankfurt city forest of various kinds Development were tested in plug-in cells. The observation took place later in Petri dishes (with the addition of salad).

Determined gst values: Trimethyltin bromide (0.5 g / m3) ....... 0.5 Triethyltin chloride (0.5 g / m3) ....... 0.5 For an experiment with ants, im Laboratory 38.5 cm 'filter paper impregnated at 20 ° C with various poison concentrations; to do this, the poisons were dissolved in acetone. In each test series there were 50 test animals directly on the poisoned paper, another 50 animals each on a copper wire gauze at a distance of 4 cm above and below the filter paper. The duration of the experiment was 24 hours.

To determine the effectiveness of the compounds, the LDSO and LDloo values were determined, with LD.o indicating the amount of poison which is necessary to cause half of the test animals to die in a certain time, while for LD ... all Animals are killed. Test results (Numerical values in -y units) With Lasius niger (black-gray garden ant) Contact ± breath poison- breath poison- Respiratory poison effect effect above below a) (CH3) 3SnC1 LDSO per 100 cm2 3.9 11.7 20.8 LD100 per 100 cm 2 20.8 52 156 b) (CH3) 3SnBr LD5o per 100 cm2 5.2 23.4 78.0 LD ... per 100 cm 2 26.0 104.0 260.0 c) (C, H5) 3SnC1 LD, per 100 cm2 52 78 104 LD ... per 100 cm2 156 156 208 d) (C2 H.) 3 Sn Br LDS0 per 100 cm2 104 156 195 LD ... per 100 cm 2 156 208 1300

Claims (2)

PATENT CLAIMS: 1. Method for controlling animal pests, preferably insects, using organic tin compounds of general Formula R, SnHal, where R is a methyl and / or ethyl group and Hal is chlorine or bromine means, characterized in that one or more of these active ingredients are used Allow room temperature in the gas phase to act on the pests. 2. The method according to claim 1, characterized by the use of methyl bromide. Considered publications: German Patent Specifications Nos. 485 646, 950 970; German Auslegeschriften M 26 296 / IVa / 451 (published e.g. on 1956), No. 1025 198; Dutch Patent No. 68,578; French patent specification No. 1 102 418.