JPS5829921B2 - Resistant leafhopper control agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 〇-ethyl〇-
0-di(2,4-dichlorophenyl) phosphate (hereinafter referred to as "phosdaifen") and diethyl 2-f-sopropyl-4-methyl-6-pyrimidinyl phosphorothionate (hereinafter referred to as "diazinon") as active ingredients. The present invention relates to a leafhopper control agent that is resistant to organophosphorus insecticides and carbamate insecticides.

The leafhopper is an important pest in rice cultivation that not only parasitizes rice plants and causes direct damage by absorbing sweat, but also transmits viral diseases such as rice wilt.

Organophosphorus insecticides have been used as control agents for rice crop pests such as leafhoppers, planthoppers, and stag beetles.

However, since the emergence of the leafhopper resistant to organophosphorus insecticides in the 1960s, N-methyl carbamate insecticides have been frequently used as leafhopper control agents.

However, in recent years, a so-called compound-resistant leafhopper, which has developed resistance not only to organophosphorus insecticides but also to N-methyl carbamate insecticides, has appeared in various parts of Japan, including western Japan, and it is difficult to find an effective control agent. The current situation is that

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

As a result, they discovered that a mixture of phosdaifen and diazinon had a greater control effect on resistant leafhopper than expected with each agent alone.

Phosdaifen, which is one of the components of the pest control agent according to the present invention, is an agricultural and horticultural fungicide described in Japanese Patent Publication No. 46-20514, and shows an excellent control effect against rice blast, but it is However, it has no insecticidal activity.

On the other hand, diazinon is reported in Japanese Patent Publication No. 30-8299 and Pesticide Handbook, 1976 edition, pages 13-20 (
It is a known agricultural and horticultural insecticide (published by the Japan Plant Protection Association), and when used as an insecticide for paddy rice, it is effective against susceptible leafhoppers, but does not have a sufficient control effect against resistant leafhoppers. do not have.

By mixing these two types of chemicals, the pesticidal agent of the present invention exhibits a high insecticidal effect against resistant leafhoppers, and is an effective agent against the same insect pests. It has the advantage of being effective against diseases and having a wide range of applications.

The pesticidal agent according to the present invention is solid, similar to general agricultural chemicals.
It can be formulated into powders, wettable powders, emulsions, granules, etc. by adding various auxiliary agents such as surfactants, dispersants, and wetting agents to a carrier such as a liquid.

Next, some examples of the present invention will be shown, but the types of adjuvants and the mixing ratio 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 diazinon, 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 Diaschiff, 1 part of white carbon, 20 parts of talc and 75 parts of clay are uniformly mixed and ground to obtain a powder.

5 Test Example 1 Resistant leafhopper control effect test A diluted solution of a predetermined concentration of the emulsion prepared according to Example 1 was applied to potted paddy rice at the 4th to 5th leaf stage at a rate of 1007 per 10 ares using a spray gun on a turntable. Spread.

After air-drying, cut the rice stem leaves to a diameter of 2 cm and a length of 20 cm.
Put 10 black leafhoppers into a test tube the size of CrIL.
The number of supine insects was determined 24 hours after the heads were released.

The leafhoppers used in the experiment were collected from Amakusa, Kumamoto Prefecture, and reared for generations, and exhibited combined resistance to organophosphorus insecticides and N-methylcarbamate insecticides.

This test was conducted in three sections with 10 animals per section, and the average supine insect rate (%
) was sought.

The results are shown in Table 1.

Note that the expected value was determined using the Bliss (B115s) formula.

Based on the data in Table 1, Carpenter
LC5o(5
The expected value (0% lethal drug concentration) was determined, 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, a synergistic value of 1 indicates an additive effect, a value smaller than ■ indicates an antagonistic effect, and a value greater than ■ 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.

Test Example 2 Changes in the susceptibility of the 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 kept at a constant temperature of 25°C under light for 16 hours and darkness for 8 hours. The rice was bred for generations using sprouted rice under the following conditions, and was subsequently subjected to culling and breeding, and drug tests were conducted from time to time.

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,
The seeds were sown in a plastic box with a size of 23 CTL x 30 cfrL x 2 CTL, and the sprouted rice seedlings were then sprayed.

This sprouted rice was placed in a cage for raising black leafhoppers, and approximately 1,000 adult black leafhoppers, which were being reared for generations, were 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 number of live and dead insects was investigated after 24 hours by topical application to adult female leafhoppers 3 to 4 days after emergence, and the LD5o value (μm/1) was determined.

The results are shown in Table 3.

Claims (1)

[Claims] It is characterized by containing 10-ethyl 0.0 di(2-dichloro* *phenyl) phosphate and diethyl 2-isofuropyru-4-methyl-6-pyrimidinyl phosphorothioate as active ingredients. A leafhopper control agent that is resistant to organophosphorus insecticides and carbamate insecticides.