IL38888A - An antimicrobial agent containing thiourea derivatives for use in agriculture and horticulture - Google Patents

Description

AN ANTIMICROBIAL AOrF.NT CONTAINING TBIOUK&A DERIVATIVES FOR USB IN AGRICULTURE AND HORTICULTURE maan rni pna ma^ ? SPECIFICATION Title of the Invention: An Antimicrobial Agent for Use in Agriculture and Horticulture, Detailed Explanation of the Invention; The present invention relates to an antimicrobial agent for use in agriculture and horticulture. As effective components of the agent, it contains compounds represented by the general formula S < A - NH - C - NH2 (1) S II wherein A represents a H2-C-NHNHCH2-NH group or a R-0-C=N R' group (wherein R represents an alkyl group, while R' represents a hydrogen atom or a methyl group. ) The inventors of this invention made a series of various studies in order to obtain a novel antimicrobial agent for use in agriculture and horticulture. As a result, we came to find that the compounds represented by the said general formula (l) above had the excellent control effect on agricultural plant diseases and also that the said compounds are possessed of a specific property of not phytotoxic to the agricultural products. Thus, such findings have led the inventors to successful achievement of the present invention.

In the following are enumerated the specific compounds containing the effective components to be used in this invention.

Compound No. Compound Name Appearance (1) Methyl N-thioureidoformimidate White pillar-like cryst (2) Ethyl N-thioureidoformimidate White pillar-like cryst (3) n-Propyl N-thioureidoformimidate White leaf-like crystal 1 (4) n-Butyl N-thioureidoformimidate White leaf-like crystal (5) Isoamyl N-thioureidoformimidate White crystalline powde I (6) Ethyl N-thioureidoacetoimidate White crystalline powde I (7) Methylene-bis-(l-thiosemicarbazide) White crystalline In the said general formula (1), the compound wherein A is represented by a R-0-C=N group can be synthesized by heat-reacting thiose- R' micarbazide with orthocarboxylic acid ester in a liquid bath in the presence or absence of alcohols.

Also in the said general formula (1), the compound wherein A is represented by a H2~jjj~NHNHCH2-NH group can be synthesized by reacting 2 mols of thiosemicarbazide with 1 mol of formaldehyde under reflux.

The following will illustrate one embodiment of the above-referred synthesis. 137 parts of thiosemicarbazide (1 mol) and 1500 parts of acetoni-trile were subjected to intimate agitation to obtain a mixture. Vith the agitation 121 parts of 35 formalin (twice the theoretical amount) were added to the mixture in drips to effect reaction thereof for two hours, under reflux. Thereafter, the resulted reaction product was cooled down to 50°C to filter the precipitated crystals formed in the course of effecting said reaction. The crystals were washed three times with acetonitrile, and were dried, to obtain 88.7 parts (91.5$) of white crystals. The decomposition point was 169°C, the ultraviolet absorption being H2O max. 230 mu.

In the next place, the superior effect of the antimicrobial agent for use in agriculture and horticulture according to the present invention will be further illustrated by way of Experimental Examples as noted below.

Experimental Example 1 The minimum inhivitory concentration of microbial growth of the compounds containing effective components according to this invention was tested by means of an agar plate dilution method. > The results are as shown in Table 1.

Table 1 * m.c.g. stands for microgram As is clear from Table 1 above, the effective components contain¬ ed in the compounds according to the present invention have a wide range of antimicrobial spectrum, the fact of which assures a great possibility of preventing various agricultural and horticultural plants from any disease (s) derived therefrom.

The mentioned effective components are capable of exhibiting a remarkably excellent effect particularly on bacterial leaf blight and canker.

I.

Experimental Example 2 Experimental Example 2 deals with an experiment in an attempt to successfully exterminate bacterial leaf blight. This was conducted in application to water surface.

As an object of the experiment, one kind of rice called, "Kinmaze" was employed. 20 seeds of "Kinmaze" were sowed in each tin-made pots, respectively having the dimensions of 15 cm x 5 cm x 5 cm. The thus sowed seeds were left as they were for 25 days. After that, the young leaves of the seedlings were inoculated with a needle which had previously been dipped into xanthomonas oryzae in a liquid form. The inoculated seedlings were permitted to stand for 24 hours in a green house at a temperature of 28°C. Thereafter, 75 ml of a liquid containing a 20% wettable powder diluted with water prepared by the process according to Example 1 was infused into each one of the seedling-grown pots, which were continuously kept in the green house for the subsequent 10 days to observe the possibility of an attack of a disease. The results are as shown in Table 2.

Table 2 (Note 1) The Effect Index referred to in the preceding Table 2 was obtained on the following calculation basis. That is, Disease Index in the treated plats Effect Index = 11 / x 100 Disease Index in the non-treated plots But; b x 3 + c x 5 Disease Index whereinj ji Number of healthy leaves b Number of slightly diseased leaves having a length of the diseased portion thereof being less than 3 cm and Number of seriously diseased leaves having length of the= diseased portion thereof being more than 3 cm (Note 2) Represents a chloramphenicol-containing agent As observed in the experimental results given in Table 3, it was proved that the antimicrobial agent for use in agriculture and horticulture claimed according to this invention does not show the phytotoxicity to rice plants and also that this antimicrobial agent is capable of exhibiting an excellent effect on them as an effective agent to be applied to water surface for use against the bacterial leaf blight to successfully exterminate the said plant disease.

In contrast, the chemical agent employed as a control proved being inferior to any one of the compounds used in respect of the practical concentration thereof.

Experimental Example 3 deals with an experiment in an attempt to successfully exterminate bacterial leaf blight. This was conducted in application to water surface.

As an object of the experiment, one kind of rice called, "Kinmaze" was employed. The rice seeds were sowed in a 1/5000 a Wagner pot and were left as they were for 30 days. Thereafter, each pot was replanted with two (2) young seedlings. The thus replanted seedlings were permitted to stand as they were for another 30 days, at which time, the growth of young head, namely, the ear of rice came to be observed. In this stage, each one of. the young leaves which just began to form the mentioned ear of rice were inoculated in one place with a needle which had previously been dipped into xanthomonas oryzae in a liquid form. The thus inoculated young leaves were permitted to stand for 24 hours in a greenhouse at a temperature of 28°C. Thereafter, 1.2 g of the 5 # granular agent prepared in a process illustrated in Example 3 was subjected to a per-pot treatment. The thus treated pots were continuously kept in the greenhouse and 20 days after the inoculation, length of the diseased portion was observed.

Table 3 - Note 1: Represents a chloramphenicol-containing agent As observed in the experimental results given in Table 3, it was proved that the antimicrobial agent for use in agriculture and horticulture claimed according to this invention is capable of exhibiting an excellent effect also on the bacterial leaf blight observed with rice in a fairly progressed stage of- growth.

Experimental Example 4 Experimental Example 4 deals with an experiment in an attempt to successfully exterminate canker. This experiment was conducted through spraying.

The leaves from two (2) summer orange (larger in. size and bitter compared with ordinary tangerines available in Japan usually during cold season through spring) in the fourth year of their growth were prepared in each one of the several unglazed pots, having the diameter of being 20 cm, respectively.

Each pot was sprayed with 50 ml of a liquid containing therein the hydrating agent diluted with water, as prepared according to the process referred to in Example 1.

After 24 hours, each one of the mentioned leaves was inoculated in one place with a needle which had previously been dipped into xanthomonas citri. 20 infusions were performed per pot. The thus inoculated leaves were continuously kept in a moist chamber for a day or two. After that, they were kept in a greenhouse to observe the inoculation effect 15 days from the removal thereof. The results are shown in Table 4.

Table 4 (Note 1) The Effect Index referred to in the preceding Table 3 was obtained on the following calculation basis. That is, Disease Index in the treated plots Effect Index a | x 100 Disease Index in the non-treated plots ) But; b + c x 2 + d x 3 Disease Index = a + b + c + d wherein; a. Number of healthy leaves t) Number of a slightly diseased leaves _c Number of a moderately diseased leaves and _d Number of a seriously diseased leaves (Note 2) Represents streptomycin, phenyl acetate mercury and a basic copper sulfate-containing agent.

As observed in the experimental results given in Table 4, it was proved that the antimicrobial agent for use in agriculture and horticulture claimed according to this invention is capable of exhibiting an excellent effect for exterminating canker in practical use as a spraying agent for the prevention thereof.

Further, the antimicrobial agent for use in agriculture and horticulture according to this invention is capable of being used in the following mode of embodiment. That is, the effective components contained in the compounds can be mixed as they are with any proper carrier, or can be used in the form of a hydrating agent, a powder, a granular agent or, depending on the need, in the form of a suspension.

Solid carriers for use as the agents include clay, kaolin, talc, diatomaceous earth, calcium carbonate and so forth.

Furthermore, various surface active agents can be added thereto depending on the need.

Further in addition, the antimicrobial agent for use in agriculture and horticulture according to this invention is capable of being used also in mixture with other antimicrobial agents for agricultural use, insecticides, nematicides, herbicides, plant growth regulating agents, soil improving agents or fertilizers.

The following will further illustrate the present invention in greater detail by way of Examples. Incidentally, the expression, "parts" in the Examples represents "parts by weight". c 4 Example 1 (Wettable powder) parts of Compound No. 1, 52 parts of kaolin, 20 parts of diatomaceous earth, 8 parts of lignin sodium sulfonate and 5 parts of alkyl sodium sulfonate were subjected to sufficient blending altogether with agitation to obtain a hydrating agent. The resultant hydrating agent can be used as a scattering agent or as a paddy field surface applying agent in water suspension. In place of said Compound No. 1, any one of the rest of the Cpmpounds No. 2 through 7 can be used in exactly the same manner as the former.

Example 2 (Dust) parts of Compound No. 1 was blended with 95 parts of talc, followed by effectipg pulverization thereto to obtain a powder agent.

The resultant agent can be used by scattering as it is. In place of said Compound No. 1, any one of the rest of the Compounds No. 2 through 7 can be used in exactly the same manner as the former.

Example 3 (Granule) parts of Compound No. 1, 20 parts of bentonite, 78 parts of talc, 1 part of lignin sodium sulfonate and 1 part of alkyl sodium sulfonate were uniformly blended together. The thus blended product was added by 16 parts of water, followed by effecting intimate kneading thereof. Thereafter, the resultant product was passed through a granulating machine having a sieve of being 1.0 to 0.5 mm. Thereafter the product was subjected to a drying treatment to obtain a granular agent.

Said product obtainable according to the above-mentioned method can be used as it is by spraying it on the surface of a paddy field.

In place of Compound No. 1, any one of the rest of the Compounds, namely those of No. 2 through No. 7 can be put to use in exactly the same manner as the former.

Claims (4)

Vhat ve Claim is;

1. An antimicrobial agent for use in agriculture and horticulture, characterized by containing therein, as effective components, compounds represented by the general formula: S I! A - H - C - NH2 S wherein A represents a NH2- group (wherein R represents an alkyl group, while R' respresents a hydrogen atom or a methyl group.)

2. An antimicrobial agent of Claim 1, wherein said effective component is a member selected from the group consisting of methyl N-thioureidoform imidate, ethyl N-thioureidoformimidate, n-propyl N-thioureidoformimidate, n-butyl N-thioureidoformimidate, isoamyl N-thioureidoformimidate, ethyl N-thioureidoacetoimidate, and methylene-bis-(l-thiosemicarbazide) .

3. An antimicrobial agent of Claim 1, wherein said effective component is mixed with a carrier.

4. An antimicrobial agent of Claim 1, wherein there is added one or more of surface active agents to said effective component. Aviv, March 1, 1972