JPS5828847B2 - Resistant leafhopper control agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 0-ethyl-
It is characterized by containing a mixture of 0-0-di(2,4-dichlorophenyl) phosphate (hereinafter referred to as "phosdaifen") and 3,5-xylyl N-methyl carbamate (hereinafter referred to as rXMcJ) as an active ingredient. This invention relates to a leafhopper control agent that exhibits resistance to carbamate insecticides.

The leafhopper is an important pest in rice cultivation that not only parasitizes rice plants and directly absorbs them, but also transmits viral diseases such as rice wilt.

Various N-methyl carbamate insecticides are frequently used because they exhibit outstanding control effects against these pests.

However, in recent years, N
- Due to the continuous use of methyl carbamate insecticides, leafhoppers that are resistant to solid agents have appeared, making it difficult to control them.

The present inventors have conducted extensive research in view of the current situation.

As a result, it was discovered that a mixture of phosdaifen and MMC exhibits a higher control effect on resistant leafhopper than expected with each agent alone.

Phosdaifen, a component of the mixture of the present invention, is
It is a known agricultural and horticultural fungicide as disclosed in Japanese Patent No. 20514, and it shows an excellent control effect particularly against blast disease, but it has almost no insecticidal activity at normal concentrations.

On the other hand, MMC is an insecticide known from pages 79 to 80 of the "Pesticide Handbook 1976 Edition" (published by the Japan Plant Protection Association), and is highly effective against susceptible leafhoppers, but not sufficiently effective against resistant leafhoppers. No pest control effect can be obtained.

By mixing these two types of chemicals, the pesticidal agent according to the present invention exhibits a high effect against resistant leafhoppers, and at the same time becomes an effective agent against the same insect pests, it is also effective against pests such as brown-bottomed planthoppers, brown planthoppers, and stink bugs, as well as against blast disease. It also has the advantage of being effective and having a wide range of applications.

Similar to widely used agricultural chemicals, the pesticidal agent according to the present invention is prepared by adding various auxiliary agents such as surfactants, dispersants, and wetting agents to a solid or liquid carrier to form powders or wettable powders. It can be used in formulations such as emulsions, granules, etc.

Next, some examples of the present invention will be shown, but the types of adjuvants, amounts added, and mixing ratios of active ingredients are not limited to the examples.

Note that all figures in the middle part of the examples indicate parts by weight.

Example 1 (Emulsion) 25 parts of phosdaifen, 25 parts of XMC, 35 parts of xylene, and 15 parts of Tulpol (emulsifier manufactured by Toho Chemical Industries, Ltd.) are mixed to prepare an emulsion.

Example 2 (Powder) 2 parts of phosdaifen, 2 parts of MMC, 1 part of white carbon
1 part, 20 parts of talc, and 75 parts of clay are uniformly mixed and pulverized to obtain a powder.

Test Example 1 Resistant black leafhopper control effect test A diluted solution of a predetermined concentration of the emulsion prepared according to Example 1 was applied to potted rice plants at the 4th to 5th leaf stage at a rate of 1001 per 10 ares on a turnchill using a spray gun. did.

After air-drying, cut the rice stem leaves to a diameter of 2 CrrL and a length of 2
Put 1 leafhopper in a test tube with a size of 0 CrrL.
The number of suppressed insects was determined 24 hours after the disappearance of 0 insects.

The test was conducted using a 1-concentration, 3-area system, and the average insect suppression rate (%) was determined.

The leafhoppers tested were collected from Amakusa, Kumamoto Prefecture and reared for generations, and are highly resistant to carbamate insecticides.

The results are shown in Table 1.

Note that the expected value was determined using the Bliss formula.

Based on the cages in Table 1, Carpenter
LC5o (50%
The expected value (lethal drug concentration) was calculated, and the synergistic effect of the insecticidal effect by mixing the active ingredients was calculated from the comparison with the actual value.

In this case, synergistic dust 1 shows an additive effect, if it is smaller than 1, it shows an antagonistic effect, and if it is larger than ■, it shows a synergistic effect.

When the number of synergistic particles is 2 or more, it indicates that the synergistic effect is significant.

The results are shown in Table 2.

7 trials, 1 test example 2 Changes in susceptibility of black leafhopper population due to continuous selection of drugs (produced in Okayama Prefecture) The black leafhopper used in the test was collected from a rice field in Kojima District, Okayama Prefecture, and then incubated at a constant temperature of 25°C for 16 hours. , sprouted rice plants were reared for generations under dark conditions for 8 hours, and then subjected to selection and rearing, and drug assays were conducted at any time.

Test 1 As a test method, first, 10 ml of a drug concentration diluted solution with a selection rate of around 50% of the test drug prepared according to Example 1 was sown in a 23 cm x 30 CTL x 21 (17) plastic box, and the seedlings were raised to sprout. Rice was sprayed.

This sprouted rice is placed in a cage for breeding black leafhoppers, and approximately 1,000 adult black leafhoppers, which have been reared for generations, are released.
After 24 hours, the surviving insects were collected with a fluke tube and released into newly prepared sprouted rice plants that were not treated with chemicals to obtain the next generation population.

Selection was repeated in the same manner, once per generation.

In the drug test, the live and dead weight of adult female leafhoppers 3 to 4 days after emergence was investigated using a local application method after 24 hours, and the LD and o values (μm/g) were determined.

The results are shown in Table 3.

(Note 1) (Note 2) L of MMC against black leafhopper from Okayama Prefecture before culling
D.

The value was 49.3μ2/g. Unselected LD.

The value column shows the LD5o of the parent adult leafhopper, the 10th generation, and the 20th generation, which have been reared for generations without chemical selection.
The values (columns before culling, after 10 times, and after 20 times in order) are shown.

Claims (1)

[Claims] 10-ethyl 0-0-di(2,4-dichlorophenyl)
A leafhopper control agent resistant to carbamate insecticides, characterized by containing a mixture of phosphate and 3,5-xylyl N-methyl carbamate as an active ingredient.