DE958968C - Pest repellants - Google Patents

Description

In pest control, the destruction of so-called hygienic pests occupies a large area. The control of the house fly (Musca domestica), which is known to be the carrier of some diseases, is carried out on a very broad basis, and in the last decade contact insecticides from the range of chlorinated hydrocarbons have been preferred. However, signs of resistance forced the search for new remedies. Organic phosphoric acid esters have also been considered for so-called hygienic pest control.

Recently, neutral phosphoric acid esters are now available became known, which is relatively with a very good insecticidal effect for warm-blooded animals are non-toxic, including O, O-dimethyl-O - 4 - nitro-3 - chloro - phenylthiophosphoric acid ester with a lethal dose of 500 mg / kg rat.

It has now been found that pesticides containing a compound of the general formula

Alkyl-O,

Alkyl —O '

.Ρ — X

NO,

where X = O or S and alkyl = methyl, ethyl, propyl or butyl means significant advances over the previously known phosphoric acid esters

bring. So is z. B. the O, O-dimethyl-O ^ -nitro-s-trifluoromethyl-phenylthiophosphate with the same toxicity for warm-blooded animals the corresponding 3-chloro-phenylthiophosphoric acid ester about six to ten times superior in effectiveness on flies, as shown in the following Examples. Of particular importance here is the fact that it is with the new products, also in aerosol form, succeed in achieving a long-term effectiveness, as is the case with the comparison substances cannot be observed.

The compounds of the above formula can be obtained by using the corresponding O, O-dialkylthiophosphoric acid chlorides Reacts in a known manner with 4-nitro-3-trifluoromethylphenol.

The compounds can also be used for general pest control, e.g. B. as Spray, dust, grit or solution, possibly in combination with other pesticides or synergists.

example 1

If one wishes to achieve in the Petri dish test with 1 cc of acetone solution per half-shell, that within 30 minutes of exposure time at 21 ⁰ all fly (Musca domestica) in constant supine position are so this is sufficient for O, O-dimethyl-O-trifluormethyM-nitrophenyl-thiophosphoric and O, O-diethyl-O-3-trinuomethyl-4-nitro-phenylthiophosphoric acid ester has a concentration of 0.005% in the solution .05% required, i.e. ten times the concentration.

Example 2

By dissolving o, i ° / ₀ , O-dimethyl-O-3-trifluoromethyl-4-nitro-phenylthiophosphoric acid ester or O, O-diethyl-Os-trmuormethyl ^ -nitro-phenylthiophosphoric acid ester in petroleum, sprays are obtained which are applied in one application rate of 2 cm ³ / m ³ space

z. B. Musca domestica immobilized in 15 to 30 minutes Move state.

If one compares this effect with that of O, O-dimethyl - O-4-nitro - 3 - chloro - phenylthiophosphate under the same conditions, it is found that of the latter a more than fivefold concentration is required.

The percentage of flies in the supine position at the age of 4 days at 27 ^{0 is} shown in the following table:

O, O-dimethyl-O-3-trinuomethyl-4-nitro-phenylthio-

phosphoric acid ester 0.1%

O, O-diethyl-O-3-trifluoromethyl-4-nitro-phenylthio-

phosphoric acid ^esters °> 10 / o

O, O-Dimethyl-O-4-nitro-3-chlorophenylthiophosphoric acid ester 0.5%

95 97 73

96

99

97

97

99

97 A comparison at 23 ⁰ between O, O-dimethyl-O -3 - trifluoro-methyl-4-nitro-phenylthiophosphoric acid ester and O, O-diethyl-Os-trifluoro-methyl ^ -nitro-phenylthiophosphoric acid ester on the one hand and the same and double concentration of O, O-dimethyl-O ^ -nitro-s-chloro-phenylthiophosphoric acid ester, on the other hand, can be seen from the following table:

O, O-dimethyl-O-3-trinuomethyl-4-nitro-phenylthio-

phosphoric acid ester 0.1%

O, O-diethyl-O-3-trinuomethyl-4-nitro-phenylthio-

phosphoric acid ester 0.1%

O, O-dimethyl-O-4-nitro-3-chlorophenylthiophosphorus

acid ester 0.2%

O, O-Dimethyl-O-4-nitro-3-chloro-phenylthiophosphoric ^{acid ester - 10} / o

To

15 I 30 I 45 Minutes

37

23

93 99 77 58

99

100

88

82

Similar, in some cases even greater, differences emerge when the substances are mixed with water Sprayed emulsion.

Example 3

An aerosol for combating flies and other insects can be prepared by mixing 5 parts by weight of O, O-dimethyl-Os-trifluoromethyl ^ -nitrophenylthiophosphoric acid ester with 6.5 parts of petroleum and 3.5 parts of dipentene and with this solution and 85 parts by weight of dichlorodifluoromethane as a propellant fills low-pressure aerosol cans in the cold. If you discharge from these doses z. B. in a closed space 0.3 g aerosol per m ^{3 of} air space, it is achieved that z. B. at a room temperature of 22 ° half of the flies (Musca domestica) after 15 minutes, about 90% after 25 minutes and the remainder are immobile on the ground by an hour at the latest and die quickly without any particular excitement. It is particularly valuable that these small amounts of aerosol make the space uninhabitable for a long time for vermin such as flies. Even after several hours of ventilation, flies that enter a room treated in this way on the following days perish within a few hours in the same inconspicuous manner.

A corresponding aerosol with O, O-dimethyl-O - 4-nitro-3-chloro-phenylthiophosphoric acid ester as an active substance acts under the same circumstances already at the beginning much slower, so that after iao Half an hour there was still no noticeable relief and after an hour no freedom from flies is reached. If one is occupied with O, O-dimethyl-O ^ -nitro-s-chlorophenylthiophosphoric acid ester Room treated in the specified manner after 3 days with flies and keeps windows and doors closed,

so the flies hardly decrease even after a further 24 hours.

Claims (1)

Claim: Pesticides, characterized by their content of a compound of general formula Alkyl-O NO, Alkyl-O ' where X = O or S and alkyl = methyl, ethyl, propyl or butyl. © 609 616/467 8.56 (609 809 2.57)