JPH01233201A - Method for strengthening miticidal activity of 2-(acetyloxy)-3-dodecyl-1,4-nephalenedione - Google Patents

Abstract

PURPOSE:To remarkably improve residual activity of the above compound and consequently improve the miticidal activity, by using the subject substance in the form of an aqueous suspension. CONSTITUTION:4 pts.wt. of polyoxyethylene phenylphenol phosphate is dissolved as a dispersing agent in a mixture of 61 pts.wt. of water and 5 pts.wt. of propylene glycol. 20 pts.wt. of the subject substance is added to the solution, thoroughly mixed and crushed with a sand mill for 35min in wet state. 10 pts.wt. of a thickener suspended in water is added to the product and crushed by mixing for 5min to obtain the objective aqueous suspension. Although the subject substance has too short residual activity to be used for practical used in the form of emulsion, wettable powder, powder, etc., the above aqueous suspension exhibits excellent residual activity in respect of miticidal activity and is sufficiently usable for practical purposes.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to 2-(acetyloxy)-3-dodecyl-1,
A method for enhancing the acaricidal activity of 4-naphthalenedione (hereinafter referred to as the present compound), which is characterized by preparing the compound into an aqueous suspension preparation, and further application of an acaricide with enhanced activity and the acaricide. The present invention relates to a method for killing mites, which is characterized by:

BACKGROUND OF THE INVENTION The present compound is a known compound described in JP-A-52-48648, and is highly effective against various spider mites, and is also highly effective against drug-resistant spider mites. However, formulations of this compound such as emulsions, wettable powders, and powders have been unable to be put to practical use to date because their efficacy rapidly decreases after application in field tests and they lack residual efficacy.

Problems to be Solved by the Invention In order to effectively control spider mites, which have a high rate of reproduction, it is necessary to maintain residual efficacy for a relatively long period of time, and the improvement in the residual efficacy of this compound is significant. It was wanted.

Means for Solving the Problems With the aim of using this compound more effectively as an acaricide, the present inventors conducted intensive research on improving the residual effect, and as a result, we developed an emulsion of this compound, a hydrated Although agents, powders, etc. have short residual effects and are not practical, an aqueous suspension preparation of this compound surprisingly has an excellent residual effect in terms of acaricidal activity and can be put to practical use. I found out that
The present invention has now been completed. In other words, the present invention makes it possible to significantly improve the residual efficacy to an extent previously unforeseeable even by those skilled in the art by making the present compound into an aqueous suspension preparation, thereby enhancing the acaricidal activity of the present compound. I am also very happy that we were able to successfully do this.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to these examples.

Formulation Example Aqueous Suspension Formulation 4 parts of polyoxyethylene phenylphenol phosphate as a dispersant may be dissolved in a mixture of 61 parts (by weight, same hereinafter) of water and 5 parts of propylene glycol, and 20 parts of the present compound may be added thereto. The mixture was mixed and pulverized for 35 minutes using a sand mill. Next, the mixture was suspended in water, 10 parts of a thickener was added thereto, and the mixture was further mixed and ground for 5 minutes to obtain an aqueous suspension preparation.

The emulsions and wettable powders used in the following test examples were prepared as follows.

Emulsion 20 parts of the present compound was dissolved in 75 parts of xylene, and 3 parts of polyoxyethylene alkyl allyl ether was added as an emulsifier.
Two parts of L-alkylbenzene sulfonate were added and the whole was thoroughly mixed and dissolved to obtain an emulsion.

Wettable powder 75 parts of clay, sodium lignin sulfonate 3B and 2 parts of higher alcohol sodium sulfate as dispersants were added to the present compound 20, and the whole was thoroughly mixed and pulverized to obtain a wettable powder.

Test Example 1 Residual Effect Test A sufficient amount of a chemical solution at a predetermined concentration was sprayed on the first leaves of potted green beans, and after air-drying, the leaves were left indoors. 1, 3, and 11 days after spraying, the primary leaves were excised and inoculated with 10 female Kanzawa spider mites per leaf piece according to the leaf disc method. Adult females were removed 48 hours after inoculation with spider mites, and 6 days later, the number of live and dead larvae was examined (repeat twice).

For each drug and each elapsed number of days, the obtained mortality rate was plotted on lognormal probability paper, and the LCss value was calculated.

Table 1 0 Take the LCss value on the vertical axis and the elapsed days on the horizontal axis as logarithmic values, calculate the relational expression between the two using the least squares method, and calculate the number of days after which the LCss value becomes 200 ppm.
I asked for As shown in Table 1, the aqueous suspension formulation of the present compound clearly showed a longer residual effect than the emulsion and wettable powder.

Test Example 2 Outdoor Field Test A field test of efficacy against citrus spider mites was conducted in Minamiashigara City, Kanagawa Prefecture. A sufficient amount of a chemical solution of a predetermined concentration was sprayed with a power sprayer on a 15-year-old early Satsuma tree infested with orange spider mites. The scale of the test plot was one tree per plot, and two consecutive plots were used. The survey was conducted before spraying, 3 days, 13 days, 22 days, and 30 days after spraying (the number of adult female citrus spider mites inhabiting 50 leaves per tree was counted. The numbers indicate the number of female adult citrus spider mites in 90 leaves of 100 leaves). shows.

As shown in Table 2, this compound is available at 50p in an aqueous suspension formulation.
Even in terms of pm, the emulsion and wettable powder showed a superior effect to 200 ppm and the comparative drug amitraz emulsion 2001)I)m.

Effects of the Invention The usefulness of the present invention lies in the fact that in the present compound, which is a known compound, an aqueous suspension preparation was found to be effective in significantly improving the residual efficacy, and the effect was enhanced to the extent that the present compound could be put to practical use. be.

Claims (3)

[Claims] (1) 2-(acetyloxy)-3-dodecyl-1,4
- A method for enhancing the acaricidal activity of naphthalene dione, which comprises preparing the compound into an aqueous suspension. (2) 2-(acetyloxy)-3-dodecyl-1,4
- An acaricide characterized in that naphthalene dione is formed into an aqueous suspension preparation. (3) 2-(acetyloxy)-3-dodecyl-1,4
- Naphthalenedione is made into an aqueous suspension and the compound is
A method for killing mites, characterized in that it is applied to plant-parasitic mites at a concentration of 0 to 2,000 ppm.