JPS5828849B2 - Resistant leafhopper control agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides O-ethyl-
〇-O-di(2,4-dichlorophenyl)phosphate (hereinafter referred to as "phosdaifen") and 1-naphthyl N-
The present invention relates to a leafhopper control agent that is resistant to carbamate insecticides and is characterized by containing a mixture with methyl carbamate (hereinafter referred to as "NAC") as an active ingredient.

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 NAC exhibited a higher control effect on resistant leafminer flint than expected with each agent alone.

Phosdaifen, a component of the mixture of the present invention, is
This is an agricultural and horticultural fungicide described in Japanese Patent Publication No. 20514, which shows particularly excellent control effects against rice blast, but does not have any insecticidal activity at normal concentrations.

On the other hand, NAC publishes the "Pesticide Handbook 1976 Edition" (
A known insecticide for paddy rice is described in pages 69 to 72 of Japanese Plant Protection Association (Published by the Japanese Plant Protection Association), and although it is highly effective against susceptible leafhoppers, it does not have a sufficient control effect on resistant leafhoppers.

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

Similar to widely used agricultural chemicals, the pesticidal agent according to the present invention is prepared by adding various Q) auxiliary agents such as surfactants, dispersants, and wetting agents to a solid or liquid carrier to form a powder or hydrate. agents, emulsions,
It can be formulated into granules and used.

Although some examples of the present invention are shown below, the types and amounts of adjuvants added and the 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 NAC, 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 NAC, 1 part of white carbon
1 part, 20 parts of talc, and 75 parts of clay were uniformly mixed and pulverized to obtain a powder.

Test Example 1 Resistant leafhopper control effect test A diluted solution of a predetermined concentration of an emulsion prepared according to Example 1 was sprayed on potted paddy rice at the 4th to 5th leaf stage at a rate of 1001 per 10 ares using a spray can on a turntable. .

After air-drying, the rice stem leaves were cut and placed in a test tube with a diameter of 2 Cr1'L and a length of 20 Cr Il, and 110 black leafhoppers were killed. 24 hours later, the number of inhibitions was determined.

The test was conducted using a three-area system with one concentration, and the average insect inhibition 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.

In addition, The expected value was determined using the Bliss equation.

Based on the data in Table 1, Carpenter
LC6° (5
0% lethal drug concentration) Find the expected value and compare it with the actual value.
The synergistic effect of insecticidal effect by mixing the active ingredients was calculated.

In this case, a synergistic value of 1 indicates an additive effect, a value less than 1 indicates an antagonistic effect, and a value greater than 2 indicates 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.

Changes in the susceptibility of the black leafhopper population due to continuous selection of drugs (from Okayama Prefecture) The black leafhoppers used in the test were collected from rice fields in Kojima District, Okayama Prefecture, and then kept at a constant temperature of 25°C under conditions of 16 hours of light and 8 hours of darkness. This is a product that has been bred for generations using sprouted rice.
These animals were then subjected to selection and rearing, and drug tests were conducted from time to 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 plastic box with a size of 23C1rlX 30C1rLX 2cm, and the sprouted rice seedlings were grown. Sprayed.

The sprouted rice was placed in a cage for raising leafhoppers, and about 1,000 adult leafhoppers were released. After 24 hours, surviving insects were collected with a fluke tube and released into newly prepared sprouted rice plants that were not treated with chemicals. , the next generation population was obtained.

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

For the drug assay, the number of live and dead spots after 24 hours was investigated using a topical application method to adult female leafhoppers 3 to 4 days after emergence, and the LD5o value (μm/?) was determined.

The results are shown in Table 3.

(Note 1) (Note 2) Before culling, the LD and o values of NAC for leafhoppers from Okayama Prefecture were 30.2 μP/P.

The LD5o value column for the unselected system shows the parent adults of leafhoppers reared for generations without chemical selection, 10th generation later, and 2nd generation.
The LD and o values after 0 generations (columns before culling, after 10 times, and after 20 times in order) are shown.

Claims (1)

[Claims] A leafhopper resistant to a carbamate insecticide characterized by containing a mixture of 10-ethyl 0-0-di(2,4-dichlorophenyl) phosphate and 1-naphthyl N-methyl carbamate as an active ingredient. Pesticide.