US2046961A

US2046961A - Insecticide

Info

Publication number: US2046961A
Authority: US
Publication date: 1936-07-07
Anticipated expiration: 1953-07-07

Description

Patented July 7, 1936 UNITED STATES 2,040,061 msEc'rIcmn I Lindley E. Mme, Midland, Micln, assig'nor to T!- Dow Chemical Company, Midland, Mick corporation of Michigan Y No Drawing. Application January 23, 1934,

- Serial No. 107,947

4 Claims. (01. 101-4 The invention relates to improvements in insecticidal compositions; and particularly to oil emulsions for use against insects, such as aphids, red spider, mealy bug, codling moth, thrips, etc.

It is among the objects of the invention to provide an effective, inexpensive composition comprising a petroleum fraction and a second ingredient, having a greater toxic value than the oil emulsion compositions heretofore known in the art at concentrations non-injurious to foliage.

To the accomplishment of the foregoing and related ends, the invention then consists of the composition of ingredientshereinafter fully described and particularly pointed out in the claims.

It is an established fact thatinsecticidal emulsions containing slightly more than 2 per cent of a petroleum oil having a sulphonation value below 35 will burn foliage sprayed therewith. Certain foliage, such as that of the pear, apple, and other fruit trees in humid weather, will not safely tolerate even this low concentration of oil. A satisfactory killing effect can not be ob:-

V tained with an oil having a sulphonation value above 85, at concentration below 2 per cent. Trichlorobenzene used alone in an emulsion will produce severe burning at concentrations above 2.0

per cent and will not kill effectively even at this;

' cent of the weight of the petroleum fraction used.

The quantity of the petroleum fraction used will depend in general upon the sulphonation value thereof, the'higher this value, the more of the fraction required to obtain the same toxicity. I

can use petroleum fractions having a sulphonation value at, any point above 50, preferably between about and about 85. Ordinarily, the per cent by weight of petroleum fraction in the finished emulsion ready for spraying will not exceed about 1.2 percent, and'the quantity of trichlorobenzene therein will not exceed about 0.4 per cent.

In the composition. prepared according-to the present invention, the oil concentration is ordinarily below 1.2" per cent and preferably below 1.0 per cent. The concentration of trichlorobenzene is preferably below about 0.4. per cent and ordinarily about 0.2 per cent. Thus the concentration of both oil and trichlorobenzene as sprayed on foliage is far below that at which any burning effect will be encountered. Now, at such low concentrations of oil andjtrichlorobenzene it would be expected that the-toxicity of theemul- 6 sion would be very low. However, we have found that the toxicity of a mixture of a petroleum fraction and trichlorobenzene is far greater than that of the sum ofthe toxicities of the individual components, as shown in the following table. 10

The table shows the comparative mortality obtained by the use of varying concentrations of mixtures of oil-and trichlorobenzene as against the individual ingredients. All of the figures given in the table indicate percentages, the per- 15 centage of oil and of trichlorobenzene being those by weight present in the emulsion, as sprayed on the foliage. The per cent mortality was determined in the following manner?- Wingless adult females of the Aphis rum-icis 20 been sprayed for 15 seconds, the aphids were re- '25 moved from the flannel with a camels hair brush and placed on a nasturtium leaf mounted in a. wide-mouth bottle having a small amount of water in. the bottom thereof. The number of dead and living aphids on the leavesat the end 30 of 24 hours was then determined.

TableI I Composition 5 Mor- Moron tan 001100]:

W on 0 11301, $2;

1.00 00 1.00 00 0.15 55 0.25- 5 0.75 0.25 91 40 0.50 40 0 5 2 g 3% .5g g3 0.2 17 0.

The foregoing table shows that the incorporation of 0.25 per cent of trichlorobenzene with 0.75 per cent of oil having a sulphonation value of between 80 and 85, in an emulsion produces a toxic value of 97 as against the additive values ofthe substances, which is 55+5 or 60. Again, at 0.50 50 per cent of each ingredient, the toxic value of the mixture is 76 contrasted with 40+12 or 52, the additive value of the separate ingredients.

As an example of my improved insecticide, I

may prepare a concentrate, in which form the 55 emulsion is usually marketed, consisting of the following:

Ingredients 4 fifigf f Petroleum fraction (suiphonation value 80) -l Trichlorobenzene 20 Sodium mseinnte 2. 0 Water. 18. 0

Petroleum fraction 0.6

Trichlorobenzene 0.2 Sodium caseinate 0.02 Water I 99.18

Sodium caseinate is employed as an emsulsifying agent, but other salts of casein, such as the potassium, calcium, or ammonium salts can also be used, as well as other known emulsifiers, such as linoleates, oleates, etc. An emulsifying agent which will give an emulsion having a particle size of 6 to 8 microns in diameter is desirable, and the caseinates produce approximately this size of particle. If the emulsions have a much smaller particle size, they do not break rapidly enough to have the best killing effect.

The optimum percentage ranges of ingredients in my finished emulsion are as follows:

Percent by weight Petroleum fraction 1.2 0.3 Trichlorobenzene 0.4 0.1 Emulsifying agent 0.04- 0.01 Water 98.36- 99.59

Among the advantages of my improved insecticidal emulsion are: '(1) it has a very high toxic value with an extremely low concentration of active ingredients; (2) it does not burn foliage at concentrations giving a high toxicity, even in very humid weather; and, (3) better colored fruit is obtained because the low concentration of oil in the finished emulsion does not cause the formation of thick oil films on fruit sprayed therewith, which may interfere with the natural coloration of the fruit by the sun's rays.

2. A composition of matter suitable for use as 25 a plant and tree spray comprising a petroleum fraction having a sulphonation value above 50, trichlorobenzene, a water soluble salt of casein, and water.

3. A composition of matter suitable foruse as a plant and tree spray comprising by weight Percent A petroleum fraction having a sulphonation value above 50 1.2 0.3 Trichlorobenzene 0.4 0.1 An emulsifying agent 004- 0.01 Water 98.36- 99.59

4. A composition of matter suitable for use as a plant and tree spray containing from 0.5 to 1.0 per cent by weight of a petroleum fraction having a sulphonation value between about and about 85, from 0.2 to 0.5 per cent of trichlorobenzene, an emulsifying agent, and water.

LINDLEY E. mm.