JPS5828851B2 - Resistant leafhopper control agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 0-ethyl-
〇-O-di(2,4-dichlorophenyl) phosphate (hereinafter referred to as "phosdaifen") and S-Cα-(ethoxycarbonyl)benzylcodimethylphosphorothiorothionate (hereinafter referred to as "PAP") as active ingredients. The present invention relates to a leafhopper control agent that is resistant to organophosphorus insecticides and carbamate insecticides, and is characterized by containing the following:

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 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, it was discovered that a mixture of phosdaifen and PAP exhibited a higher control effect on resistant leafhopper than expected from each agent alone.

Phosdaifen, which is one of the components of the pest control agent according to the present invention, is a known agricultural and horticultural fungicide as disclosed in Japanese Patent Publication No. 46-20514, and shows an excellent control effect against rice blast, but at a conventional concentration. It has no insecticidal activity.

On the other hand, PAP is an insecticide known from Japanese Patent Publication No. 35-8250, 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, as well as pests such as brown-bottomed planthoppers, brown-bottomed planthoppers, snail bugs, and stink bugs, as well as rice blast disease. It has the advantage of being effective against a wide range of applications.

The pesticidal agent according to the present invention is solid, similar to general agricultural chemicals.
It can be used by adding various auxiliary agents such as surfactants, dispersants, and wetting agents to a carrier such as a liquid to formulate powders, wettable powders, single emulsion tablets, and the like.

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 PAP, 35 parts of xylene, and 1 part of Tulpol (emulsifier manufactured by Toho Chemical Industry Co., Ltd.)
Mix 5 parts to form an emulsion.

Example 2 (Powder) * * 2 parts of phosdaifen, 2 parts of PAP, 1 part of white carbon, 20 parts of talc and 5 parts of flakes are uniformly mixed and ground 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 out the leaves of the rice stalks to a size of 2 cm in diameter.
Ten black leafhoppers were dispersed in a test tube with a length of 20 shots, and the suppressed weight was determined 24 hours later.

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

This test was conducted in three sections with 10 animals per section, and the average suppression 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
LC50(5
The expected value (0% lethal drug concentration) was determined, and the degree of synergy of the insecticidal effect by mixing the active ingredients was calculated from the comparison with the actual value.

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

When the degree of synergy 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 (from Okayama) The black leafhoppers used in the test were collected from a rice field in Kojima District, Okayama Prefecture, and then exposed to light for 16 hours at a constant temperature of 25°C for 8 hours. The sprouted rice plants were bred for generations under dark conditions, and were subsequently subjected to selection and breeding, and drug assays were conducted as needed.

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 plastic boxes measuring 23 CTL x 30 Crn x 2 cm, and sprouted rice plants were treated with the spray.

The sprouted rice was placed in a breeding cage for black leafhoppers, and approximately 1,000 black leafhopper fR insects were released, and 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. The next generation population was obtained.

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

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

Claims (1)

[Claims] 10-ethyl 0-0-di(2,4-dichlorophenyl)
A leafhopper control agent resistant to organophosphorus insecticides and carbamate insecticides, characterized by containing phosphate and s'-cα-(ethoxycarbonyl)benzyl codimethyl phosphorothiolothionate as active ingredients.