JPH072611B2 - Pest repellent - Google Patents

Description

TECHNICAL FIELD The present invention relates to a repellent for the purpose of controlling pests such as sanitary pests and crop pests.

[Prior art and problems]

It goes without saying that conventional synthetic pesticides have made great contributions to the control of pests, but on the other hand, they have been accompanied by risks such as environmental pollution, food residue and chronic toxicity.

In addition, the insecticidal power is strong and non-selectively kills insects, thus destroying the balance of the ecosystem, causing abnormal occurrence of pests and causing insects that were not pests until now.

[Means for solving problems]

Although plants produce a wide variety of secondary metabolites in order to protect themselves from foreign enemies, the present inventors have found that plants that are relatively less susceptible to feeding damage by foreign enemies include substances that cause repellent action against pests. I think that they must be present, and paying attention to them, I have searched for pest repellents that have a large guarantee for safety and do not disturb the balance of the ecosystem. As a result of further research on Ginkgo biloba L, which shows extremely remarkable resistance to feeding damage, it was found that ginkgo biloba extract has repellent action against various pests. . Furthermore, it was found that 6-alkenylsalicylic acids and terpenes such as ginkgolide and bilobalide contained in the extract were the causative substances of the repellent action. That is, the present invention provides a pest repellent containing a ginkgo biloba extract as an active ingredient.

The pest repellent of the present invention not only exhibits feeding repellent action against crop insects of the order Lepidoptera, such as caterpillars and bollworms, but also sanitary pests such as cockroaches, flies, mosquitoes, flies, bed bugs and blood-feeding pests, It also has a repellent effect against clothing pests such as squid and carp, stored grain pests such as stag beetle, weevils, and ants, termites and slugs.

In order to obtain the ginkgo biloba extract used for the pest repellent of the present invention, the green leaves of ginkgo biloba may be subjected to extraction treatment with water or an organic solvent, and as the organic solvent, alcohols such as methanol, ethanol, propanol and butanol, acetone,
Ketones such as methyl ethyl ketone, esters such as ethyl acetate and butyl acetate, and fatty solvents such as petroleum ether, hexane and carbon tetrachloride can be used. In addition, the active ingredient may be concentrated by devising the extraction method depending on the target pest.

The ginkgo biloba extract of the present invention has various components, but includes 6-alkenylsalicylic acids, sesterpenes such as bilobalide and ginkgolide, and terpenes such as diterpenes. The alkenyl group of 6-alkenylsalicylic acid here has a carbon number of 13 to 17 having a double bond at the 8- to 12-positions.

For example, since 6-alkenylsalicylic acids are more effective against molluscs, when dry leaves are extracted with a fat-soluble solvent, raw leaves are extracted with a hydrophilic organic solvent and then distributed extraction is performed with a fat-soluble organic solvent. By doing so, the active ingredient may be concentrated.

Further, if necessary, it is possible to decolorize using an adsorbent such as activated carbon.

Although the pest repellent of the present invention can be applied to the place where the pest repellent is required, the extract as it is,
Generally, it is preferably prepared by using a suitable carrier or other compounding agent into various forms suitable for the application area, application method, etc., such as a liquid formulation, a solid formulation, etc. The pest repellent of the present invention as a solvent may be further blended with usual additives such as a film-forming agent, an emulsifier, a dispersant, a spreading agent, a wetting agent, a stabilizer and a spraying agent. It can be used in the form of adhesives, emulsions, dispersants, suspensions, lotions, creams, sprays, aerosols and the like.

In addition, mineral powder such as silicic acid, activated carbon and bentonite,
It can also be used as a solid formulation prepared by using plant powders such as wood flour and starch and inclusion compounds such as cyclodextrin as carriers. Further, the pest repellent of the present invention should be mixed with known pest repellents, potency enhancers, antioxidants, decomposition agents, bactericides, defensive agents, herbicides, fertilizers, flavoring agents, coloring agents and the like. You can

The pest repellents of the present invention thus prepared having various forms are used for invading areas of pests which are required to have repellent effects upon their use, such as crop cultivation fields, orchards, general households, grain warehouses, cafeteria kitchens, It can be applied to storage furniture, closets, entrances, washrooms, etc. by spreading, spraying, spraying, applying, pasting, etc., or spraying, spraying, applying, etc. on animals and plants themselves.

The amount of the active ingredient of the pest repellent of the present invention and the amount of the repellent applied may be appropriately determined depending on the dosage form, application method, application site, etc. 1 to 100% by weight, preferably 5 to 50% by weight of the effective extract, in the case of solid agents such as powders 1
-50% by weight, preferably 2-20% by weight, and the application amount is, for example, in the case of coating use, the area to be coated is 1
The active ingredient is preferably about 0.01 mg / cm ² or more, preferably 0.01 to 1 mg, and when used in a solid formulation or other form, it is suitable that 10 mg or more of the active ingredient is present per 1 m ^{2 of} the application space.

〔Example〕

 The effect will be described by way of examples.

Example 1 5 g of fresh ginkgo biloba was heated and refluxed in 20 liters of methanol for 4 hours, and the methanol solution obtained by filtering off the leaves was concentrated to obtain 270 g of an extract.

Example 2 30 kg of dried ginkgo biloba was heated and refluxed in 220 l of methanol for 4 hours, and the methanol solution obtained by filtering off the foliage was concentrated to dryness to obtain 4.8 kg of an extract.

Example 3 An acetone solution containing 1.5% of the extract obtained in Example 2 was applied to a filter paper having a diameter of 15 cm, the acetone was volatilized, the mixture was moistened with a sucrose solution and placed in a petri dish, and slugs were placed on it.
I placed 20 of them. After 2 hours, the number of slugs on the filter paper was counted and compared with a control treated with an acetone solution containing no Ginkgo biloba extract. The repellent rate [100-100 × (number of slugs on the filter paper containing the sample) / (number of slugs on the control filter paper)] was 98%.

Example 4 On a moistened filter paper in a petri dish having a diameter of 10 cm, a rubber lattice in which 12 holes having a diameter of 1 cm were circularly formed was placed, and a leaf disk of cabbage (a portion having a small vein of cabbage leaf was selected in the hole). The one with the cork borer punched in) was prepared for the repellent test. 1 of the extract obtained in Example 1
A% acetone solution and an acetone solution containing no extract were alternately applied on a leaf disk to volatilize the acetone, and then two caterpillars were put in to observe feeding behavior. After 16 hours, the caterpillar was removed and the feeding repellency rate [100-100 × (weight of sample disk eaten) / (weight of control disk eaten)] was examined. As a result, the repellency rate was 87%.
Met.

Example 5 The extract obtained in Example 1 was partitioned with hexane and methanol, and the hexane solution was concentrated to give an oil of 0.3%.
% Ethanol solution was prepared. After applying this to the upper arm of a healthy adult male, insert it for 1 minute into a cage in which about 50 female adults 5 to 7 days after emergence were released and apply it with the number of blood-sucking traces of the arm to which the repellent was applied. As a result of comparing the number of blood-sucking traces of unarmed arm, the repellency rate [100-100 × (number of blood-sucking traces of applied arm)
/ (Number of blood-sucking traces of arm not applied)] was 83%.
No abnormalities such as dermatitis, which could be a concern when the repellent was applied directly to the skin, were observed.

Example 6 Half of a petri dish having a diameter of 20 cm was coated with the same repellent as that used in Example 5, the solvent was sufficiently evaporated, and 50 human fleas were released into the petri dish. After standing for 5 minutes, anesthesia was performed with chloroform vapor, and the number of human fleas (Ns) in the area where the repellent was applied was compared with the number of human fleas (Nc) in the area that was not applied. 100 x Ns / N
c) was 87%.

Claims (2)

[Claims] 1. A pest repellent comprising a ginkgo biloba extract as an active ingredient. 2. The pest repellent according to claim 1, wherein the ginkgo biloba extract contains 6-alkenylsalicylic acid or sesquiterpenes such as bilobalide and ginkgolide and diterpenes.