Meloidogyne control agent

Abstract

To provide a control agent that is easily available and can control meloidogyne without adverse effects on crops and workers, and a meloidogyne control method using the same.SOLUTION: The present invention provides a meloidogyne control agent comprising at least one basic amino acid selected from the group consisting of histidine, ornithine, arginine, and lysine, or at least one antioxidant component selected from the group consisting of cysteine, ascorbic acid, glucosamine, and hydroxyphenylacetic acid.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control agent for controlling root-knot nematodes that parasitize the roots of agricultural crops. [Background technology]

[0002] Nematodes (nematodes) are a general term for animals belonging to the phylum Nematoda, and there are a great many species. Most of these nematodes are harmless to humans, but some are known to parasitize and cause damage to plants. Examples include root-knot nematodes, cyst nematodes, and root-lesion nematodes. Among these, root-knot nematodes, such as Meloidogyne niger and Meloidogyne incognita, parasitize the roots of agricultural crops such as potatoes, carrots, and strawberries, causing the roots to rot and promoting the occurrence of soil diseases such as bacterial wilt. It is said that about 5% of pest damage to agricultural products worldwide is caused by these root-knot nematodes. To deal with such damage caused by root-knot nematodes, highly toxic pesticides based on fumigants (methyl bromide) and organophosphate compounds, the use of which is prohibited in Europe and the United States, are used in Japan.

[0003] However, spraying such chemicals is undesirable from the standpoint of the safety of crops and workers. In particular, if nematode infection is observed during the cultivation of agricultural crops, such highly toxic chemicals cannot be used on the crops. For this reason, a method for eradicating root-knot nematodes while maintaining the safety of crops and workers is desired.

[0004] Patent Document 1 discloses the use of alkylbenzenes with specific substituents to eradicate nematodes such as root-knot nematodes, but the effects of such compounds on agricultural crops are unknown and not mentioned in the document.

[0005] One of the co-applicants of the present application has disclosed a root-knot nematode control agent containing an extract of Bidens pilosula and wood vinegar as active ingredients (Patent Document 2), and a root-knot nematode control agent containing a specific organic acid and dicarboxylic acids as active ingredients (Patent Document 3).

[0006] The other applicant of the present application is a cellular slime mold belonging to the genus Dictyostelium. They discovered that a substance repels root-knot nematodes and succeeded in producing a repellent from its secretions (Patent Document 4). Cellular slime molds are eukaryotic microorganisms that live universally in soil and usually grow in a single-cell state by feeding on bacteria.

[0007] The co-applicant of the present application has disclosed a formulation for controlling root-knot nematodes that contains ethyl α-D-glucoside as an agent for controlling root-knot nematodes (Patent Document 5). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 7-25707 [Patent Document 2] JP 2013-184890 A [Patent Document 3] JP 2017-1988 A [Patent Document 4] Patent No. 6172545 [Patent Document 5] Patent No. 6821158 Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, some of the conventional root-knot nematode control agents and repellents are harmful as agricultural chemicals, and those derived from specific plant varieties or organisms such as slime molds require complicated production processes such as extraction or the preparation of large amounts of the organism. Therefore, the object of the present invention is to provide a novel root-knot nematode control agent that can be easily prepared or obtained and has high control activity even in small amounts. [Means for solving the problem]

[0010] According to a first aspect of the present invention, there is provided a root-knot nematode control agent comprising at least one basic amino acid selected from the group consisting of histidine, ornithine, arginine and lysine. The histidine may be an oligomer of histidine.

[0011] According to a second aspect of the present invention, there is provided an agent for controlling root-knot nematodes, which comprises at least one antioxidant component selected from the group consisting of cysteine, ascorbic acid, glucosamine, and hydroxyphenylacetic acid.

[0012] The root-knot nematode control agent of the present invention may further contain an inorganic or organic carrier, and the basic amino acid or the antioxidant component may be supported on the inorganic or organic carrier. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 shows the arrangement of samples containing a control ingredient and root-knot nematodes in a petri dish used in Examples 1 and 2. [Diagram 2] Figure 2(a) is a composite microscopic photograph showing the behavior of Meloidogyne incognita in the absence of a sample containing histidine (Control), and Figure 2(b) is a composite microscopic photograph showing the behavior of Meloidogyne incognita in the presence of a sample containing histidine. [Diagram 3] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing histidine in regions 1 and 2 in comparison with a control in Example 1. [Figure 4] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing ornithine in regions 1 and 2 in comparison with a control in Example 2. [Diagram 5] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing arginine in regions 1 and 2 in comparison with the control in Example 3. [Figure 6] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing lysine in regions 1 and 2 in comparison with the control in Example 4. [Figure 7] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing cysteine ​​in regions 1 and 2 in comparison with the control in Example 5. [Figure 8] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing ascorbic acid in areas 1 and 2 in comparison with the control in Example 6. [Figure 9] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing glucosamine in areas 1 and 2 in comparison with the control in Example 7. [Figure 10] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing 4-hydroxyphenylacetic acid in areas 1 and 2 in comparison with the control in Example 8. [Figure 11] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing secretions (culture supernatant: CM) from cellular slime mold in regions 1 and 2 in comparison with the control in Example 1. [Figure 12] This is a conceptual diagram showing the arrangement of Lotus japonicus samples No. 2 and No. 3 placed away from Lotus japonicus sample No. 1 on a plate, close to a piece of filter paper containing a pest control ingredient, and Lotus japonicus nematodes placed below each of the Lotus japonicus samples. [Figure 13] This is a graph showing the infection rate of Meloidogyne incognita in Lotus japonicus roots of samples No. 1 to 3 when using pieces of filter paper soaked in only 40% methanol, pieces of filter paper containing a control ingredient (histidine), and pieces of filter paper soaked in a secretion of cellular slime mold. [Figure 14] This is a graph showing the infection rate of Meloidogyne incognita in Lotus japonicus roots of samples No. 1 to 3 when using pieces of filter paper soaked only with 40% methanol, pieces of filter paper containing control ingredients (cysteine, ornithine, lysine), and pieces of filter paper soaked with secretions of cellular slime mold. [Figure 15] This is a graph showing the infection rate of Meloidogyne incognita in Lotus japonicus roots of samples No. 1 to 3 when using pieces of filter paper soaked in only 40% methanol, pieces of filter paper containing control ingredients (ascorbic acid, arginine), and pieces of filter paper soaked in secretions of cellular slime mold. [Figure 16] This is a graph showing the infection rate of Meloidogyne incognita in Lotus japonicus roots of samples No. 1 to 3 when using filter paper pieces soaked in only 40% methanol, filter paper pieces containing a control ingredient (4-hydroxyphenylacetic acid), and filter paper pieces containing a secretion of cellular slime mold. [Figure 17] This is a graph showing the infection rate of Meloidogyne incognita in Lotus japonicus roots of samples No. 1 to 3 when using pieces of filter paper soaked only with 40% methanol, pieces of filter paper containing a control ingredient (glucosamine), and pieces of filter paper containing a secretion of cellular slime mold. [Figure 18] 1 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing histidine oligomers in regions 1 and 2 in comparison with a control. [Figure 19] 13 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing potato peptone in areas 1 and 2 in comparison with the control and CM in Example 9. [Figure 20]In Example 10, this is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing peptones other than potato peptone and yeast extract in areas 1 and 2, in comparison with the control, CM, and potato peptone. [Figure 21] 11 is a graph quantitatively showing the presence of Meloidogyne incognita in samples containing proteose peptone, tryptone and BD yeast extract in regions 1 and 2 in comparison with the control and CM in Example 10. [Figure 22] This is a graph showing the infection rate of Meloidogyne incognita in Lotus japonicus roots of samples No. 1 to 3 when using pieces of filter paper soaked only in sterilized water, pieces of filter paper soaked in secretions of cellular slime mold, and pieces of filter paper soaked in potato peptone. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the root-knot nematode control agent of the present invention will be described.

[0015] The present inventors have found that a control agent containing a specific control component can effectively repel root-knot nematodes. The specific control components are divided into two types: the specific basic amino acids described below and the specific antioxidant components described below.

[0016] The basic amino acid is histidine, ornithine, arginine, or lysine, or any mixture thereof. The antioxidant component is cysteine, ascorbic acid, glucosamine, or hydroxyphenylacetic acid, or any mixture thereof. The basic amino acid or antioxidant component can effectively repel root-knot nematodes without withering agricultural crops, killing living organisms, or causing adverse effects on workers. Of the basic amino acids, histidine is preferred in terms of availability. Of the antioxidant components, cysteine ​​and ascorbic acid are preferred in terms of availability.

[0017] The basic amino acid may be histidine, ornithine, arginine or lysine alone. The mixture of basic amino acids may contain all of histidine, ornithine, arginine and lysine, or may contain any three or two of them. For example, it may contain histidine, arginine and lysine. In addition, as long as it contains at least one of the basic amino acids, it may contain other components. Histidine, ornithine, arginine or lysine exist in L-type and D-type, and it has been found from the examples described below that L-type is effective.

[0018] The antioxidant component may be cysteine, ascorbic acid, glucosamine, or hydroxyphenylacetic acid alone. The antioxidant component may contain all of cysteine, ascorbic acid, glucosamine, or hydroxyphenylacetic acid, or may contain three or two of them. In addition, other components may be contained as long as at least one of the antioxidant components is contained. Cysteine, ascorbic acid, and glucosamine are available in L-type and D-type, and it has been found from the examples described below that the L-type is at least effective for cysteine ​​and ascorbic acid, and the D-type is at least effective for glucosamine.

[0019] Peptone is a general term for a mixture of amino acids and low molecular weight peptides obtained by hydrolysis of proteins. Various peptones exist depending on the raw materials and manufacturing processes. For example, casein peptone, meat peptone, gelatin peptone, potato peptone, wheat peptone, rice peptone, soybean peptone, etc. are available. For example, potato peptone contains histidine, arginine, lysine and cysteine, so it can be used as a control component containing the above basic amino acids and / or the above antioxidant components. As other peptones, any peptone can be used as long as it contains the above basic amino acids and / or antioxidant components. Examples of such peptones include Bacto peptone (manufactured by Becton Dickinson (BD)), soybean peptone (manufactured by Solabia Biokar Diagnostics), Kyokuto peptone (manufactured by Kyokuto Pharmaceutical Industries), and proteose peptone (manufactured by BD). Proteose peptone (BD) is known to contain at least histidine, arginine, lysine and cysteine. Among these, potato peptone is preferred because it has excellent control effects as shown in the results of the Examples described later.

[0020] In addition to peptone, extracts such as yeast extract (Kyokuto Pharmaceutical Industries, Ltd. or BD Co., Ltd., etc.) and tryptone (Hanai Co., Ltd., etc.) can be used. Yeast extract (Kyokuto Pharmaceutical Industries, Ltd. or BD Co., Ltd.) and tryptone (Hanai Co., Ltd.) are known to contain at least histidine, arginine, lysine, and cysteine.

[0021] In addition, as for histidine, its oligomers have also been confirmed to have a control effect against root-knot nematodes, as shown in the test results described below.

[0022] The control agent of the present invention may contain other additives in addition to the control component. Examples of other additives include fertilizers, agricultural chemicals, soil conditioners, plant activators, and plant growth regulators. The control agent may also be formulated using known additives. Examples of the formulation include liquids such as emulsions, wettable powders, water-soluble agents, suspensions, oils, and flowables; solids such as powders, fine granules, granules, tablets, microcapsules, and films; smoking agents; fumigants, and aerosols. Examples of additives include carriers (diluents), surfactants, spreading agents, emulsifiers, wetting agents, dispersants, and disintegrants. Inorganic and organic porous carriers such as zeolite, perlite, plant fibers, activated carbon, and diatomaceous earth can be used as carriers for supporting the control component. Other pesticide active ingredients such as nematode control agents, antibacterial agents, insecticides, and herbicides other than the control component may also be used. As another nematode control agent, for example, a root-knot nematode control agent containing an extract of Bidens pilosula and wood vinegar as active ingredients may be mixed with the control agent of the present invention and used as a mixture or composition. Note that the control agent of the present invention may be the above-mentioned control component alone.

[0023] <Objects to be controlled> Root-knot nematodes, root-leak nematodes, and cyst nematodes are known as plant-parasitic nematodes that parasitize the roots of agricultural crops. In the present invention, however, root-knot nematodes are targeted for repelling, and in particular, root-knot nematodes such as Meloidogyne hapla, Meloidogyne incognita, Meloidogyne javanica, and Meloidogyne arenaria are targeted for control.

[0024] <How to control root-knot nematodes> The root-knot nematode control agent of the present invention can repel or control root-knot nematodes by applying it to soil or plants on which root-knot nematodes are parasitic. Examples of such plants include sweet potato, potato, bell pepper, eggplant, radish, Chinese cabbage, taro, soybean, strawberry, tomato, watermelon, melon, onion, peanut, carrot, burdock, Chinese yam, corn, asparagus, grapes, etc. The soil is not limited to farmland, and may be an artificial field or area such as a plant factory.

[0025] The control agent of the present invention can be applied to soil such as farmland by any method. In the case of a solid agent, it can be sprayed, mixed, laid, buried, etc. in the soil, and in the case of a liquid agent, it can be irrigated or mixed into the soil, sprayed on the soil surface, or soaked in plant roots or seeds. Any method and device can be used for spraying or spraying. Alternatively, it can be mixed with pesticides or fertilizers and sprayed on farmland, etc.

[0026] When the control agent of the present invention is irrigated into soil, the concentration of the control component is adjusted to about 1 to 10,000 ppm, preferably 2 to 1,000 ppm, and an irrigation device or the like is used to irrigate about 10 to 5,000 ml per plant during the cultivation period, about once a day to once a month, depending on the growth of the plant and the degree of damage.

[0027] The control agent will be specifically described below with reference to the following examples and comparative examples, but the present invention is not limited thereto.

[0028] 1. Repellent effect against root-knot nematodes First, the following experiment was carried out to investigate the repellent behavior or control effect of various control components on the sweet potato root-knot nematode.

[0029] Example 1: Histidine L-histidine (hereafter simply referred to as "histidine") was dissolved in 40% methanol to a concentration of 5 mg / ml as a control ingredient. 0.1 ml of this solution was dropped onto a piece of filter paper and dried. The dried piece of filter paper was used as a sample (0.5 mg of histidine) and placed on the left side of a petri dish containing gellan gum (Nacalai Tesque) as shown in Figure 1. Eight to sixteen root-knot nematodes were seeded at a position (seeding position) 1.2 cm away from the sample toward the center of the petri dish. 16 hours after seeding, the behavior of the root-knot nematodes was observed under a microscope (Nikon AZ100 Multizoom microscope).

[0030] Figure 2(a) shows the sweet potato cat (control) sample that does not contain histidine. Figure 2(b) is a micrograph showing the behavior of Meloidogyne incognita in a sample containing histidine. The black vertically elongated area on the left edge of the photograph is the piece of filter paper, and the black area in the center is the area where Meloidogyne incognita was seeded. The photographs were taken using a digital camera for microscopes (Flobel FR-400C). After that, the images were stitched together and image processing was performed to show the entire area of ​​the petri dish. As shown in Figure 2(a), in the control, the movement of the sweet potato root-knot nematodes covers the entire surface of the petri dish. This shows that the sweet potato root-knot nematodes behave randomly. On the other hand, as shown in Figure 2(b), all of the sweet potato root-knot nematodes were observed to be avoiding the histidine on the left side of the petri dish. This observation shows that histidine is an effective component for controlling sweet potato root-knot nematodes.

[0031] To quantitatively analyze the behavior of the root-knot nematode, the footprints of the nematode were scanned and quantified in area 1 (area close to the filter paper) divided to the left of the sowing position and area 2 (area far from the filter paper) divided to the right of the sowing position. The size of each area was 0.95 x 1.3 cm, and the distance between area 1 and area 2 was 0.27 cm. Specifically, each area was photographed after 16 hours using a digital camera for a microscope, and the number of dots was counted and quantified using the image analysis software ImageJ to determine the extent to which the root-knot nematode had moved in each area.

[0032] A similar experiment was also conducted on the control sample. The results obtained by image analysis are shown in the table in Figure 3. The relative amount on the vertical axis in Figure 3 is expressed as the area ratio of each region to the total area of ​​the movement trajectory of the sweet potato root-knot nematode. It can be seen that the sample containing 0.5 mg of histidine significantly repelled the sweet potato root-knot nematode compared to the control without histidine.

[0033] The same experiment was carried out by changing the amount of histidine in the sample to 0.1 mg and 0.01 mg, respectively. The results are also shown in the table in Figure 3. It was found that histidine significantly repels the root-knot nematode even at an amount of at least 0.1 mg.

[0034] Example 2: Ornithine The same experiment as in Example 1 was carried out, except that L-ornithine (hereinafter simply referred to as "ornithine") was used as the control component. In addition, the amount of ornithine in the sample was changed to 0.1 mg and 0.01 mg, respectively, and the same experiment was carried out. The results are shown in the table of Figure 4. It was found that ornithine significantly repels the sweet potato root-knot nematode even in an amount of at least 0.1 mg.

[0035] Example 3: Arginine The same experiment as in Example 1 was carried out, except that L-arginine (hereinafter simply referred to as "arginine") was used as the control component. In addition, the amount of arginine in the sample was changed to 0.1 mg and 0.01 mg, respectively, and the same experiment was carried out. The results are shown in the table of FIG. 5. It was found that arginine significantly repels the sweet potato root-knot nematode even in an amount of at least 0.01 mg.

[0036] Example 4: Lysine The same experiment as in Example 1 was carried out, except that L-lysine (hereinafter simply referred to as "lysine") was used as the control component. In addition, the amount of lysine in the sample was changed to 0.1 mg, 0.01 mg, and 0.005 mg, and the same experiment was carried out. The results are shown in the table of FIG. 6. It was found that lysine significantly repels root-knot nematodes even in an amount of at least 0.005 mg.

[0037] Example 5: Cysteine The same experiment as in Example 1 was carried out, except that L-cysteine ​​(hereinafter simply referred to as "cysteine") was used as the control component. In addition, the amount of cysteine ​​in the sample was changed to 0.1 mg, 0.05 mg, 0.01 mg, and 0.005 mg, and the same experiment was carried out. The results are shown in the table of FIG. 7. It was found that cysteine ​​significantly repels root-knot nematodes even in an amount of at least 0.005 mg.

[0038] Example 6: Ascorbic Acid The same experiment as in Example 1 was carried out, except that L-ascorbic acid (hereinafter simply referred to as "ascorbic acid") was used as the control ingredient. In addition, the amount of ascorbic acid in the sample was changed to 0.1 mg and 0.01 mg, respectively, and the same experiment was carried out. The results are shown in the table of FIG. 8. It was found that ascorbic acid significantly repels the sweet potato root-knot nematode even in an amount of at least 0.01 mg.

[0039] Example 7: Glucosamine The same experiment as in Example 1 was carried out, except that D-glucosamine (hereinafter simply referred to as "glucosamine") was used as the control component. In addition, the amount of glucosamine in the sample was changed to 0.1 mg, 0.01 mg, and 0.005 mg, and the same experiment was carried out. The results are shown in the table of FIG. 9. It was found that even an amount of glucosamine of at least 0.005 mg in the sample significantly repels the sweet potato root-knot nematode.

[0040] Example 8: 4-Hydroxyphenylacetic acid The same experiment as in Example 1 was carried out, except that 4-hydroxyphenylacetic acid was used as the control ingredient. In addition, the amount of 4-hydroxyphenylacetic acid in the sample was changed to 0.1 mg and 0.01 mg, respectively, and the same experiment was carried out. The results are shown in the table of Figure 10. It was found that 4-hydroxyphenylacetic acid significantly repels the sweet potato root-knot nematode even in an amount of at least 0.5 mg.

[0041] <Reference example: Test using secretions from Dictyostelium genus cellular slime mold> As disclosed in Patent Document 4 (JP Patent No. 6172545), the inventor of the present application has developed a repellent for repelling root-knot nematodes, the active ingredient of which is a substance secreted from a cellular slime mold belonging to the genus Dictyostelium, and an experiment was conducted under the same conditions as in the above examples using 5 mg of this repellent. The control agent was prepared as follows according to the method disclosed in JP Patent Publication No. 2020-186233 disclosed by the same inventor.

[0042] Dictyostelium discoideum KAx3 cells were seeded in a flask containing synthetic medium HL-5, and the cell number was 1x10 7The cells were cultured at 150 rpm on a shaker until they reached 1x10 cells / ml (stationary phase), and then the cells and medium were centrifuged in a centrifuge to separate the cells from the synthetic medium. The medium became the supernatant in the centrifuge tube, and the cells were solidified in a pellet form at the bottom of the tube. To wash away the medium remaining on the cells, phosphate buffer was added to the centrifuge tube to suspend the cells, and the tube was centrifuged again. The centrifuged supernatant was discarded, and phosphate buffer was added again to the centrifuge tube with the cells remaining at the bottom, and the cells were thoroughly suspended by stirring. The cell concentration in the suspension was 1x10 8 The concentration of the conditioned medium was adjusted to 100 cells / ml, transferred to a flask, and static culture was performed at 22°C for 72 hours. After that, the cells were centrifuged to obtain the supernatant. This supernatant is called conditioned medium (hereinafter abbreviated as "CM"). The CM was dried using a rotary evaporator, the weight of the dried product was measured, and the solution was dissolved in 40% methanol to a concentration of 100 mg / ml. This was used to observe the repellent behavior of M. incognita.

[0043] Next, the concentration of CM was adjusted to 50mg / ml and 2mg / ml, and 0.1ml of each was soaked into a piece of filter paper so that 5mg and 0.2mg of CM were contained per piece of filter paper, and similar experiments were performed. The results are shown in Figure 11. From the graph in Figure 11, it can be seen that about 5mg of the secretion from the cellular slime mold of the genus Dictyostelium is required to obtain a control effect. From this result, it can be said that even a small amount of the control component used in the above example exerts a control effect against sweet potato root-knot nematode.

[0044] Example 9: Potato peptone The same experiment as in Example 1 was carried out except that potato peptone (manufactured by Kyokuto Pharmaceutical Industries Co., Ltd.) was used as the control component, and the amount of potato peptone was changed to each value in the range of 5.0 mg to 0.01 mg as shown in FIG. 19. As a comparative sample, the content of pure water (MilliQ) and CM prepared in the same manner as in the above Reference Example was changed to each value in the range of 7.5 mg to 0.1 mg as shown in FIG. 19, and the same experiment as in Example 1 was carried out. The results are shown in FIG. 19. Even with a small amount of potato peptone, the relative amount exceeded 70%, and it was found to significantly repel sweet potato root-knot nematodes. Considering that histidine, arginine and lysine are contained in only about 13% of the amino acids contained in potato peptone, potato peptone can be a more effective control component than the above basic amino acids alone, even though it is a small amount, and is also preferable in that it is easily available.

[0045] Example 10: Peptones other than potato peptone The same experiment as in Example 1 was carried out, except that Bacto peptone (manufactured by BD), soybean peptone (manufactured by Solabia Biokar Diagnostics), Kyokuto peptone (manufactured by Kyokuto Pharmaceutical Industries), and Kyokuto yeast extract (manufactured by Kyokuto Pharmaceutical Industries) were used as the control components in the samples. In this experiment, the amount of the control components in the samples was changed to 0.7 mg, 0.14 mg, and 0.028 mg, respectively. The results are shown in FIG. 20. As comparative samples, the same experiment as in Example 1 was carried out on the same day using pure water (MilliQ), CM (3.5 mg, 0.7 mg, and 0.14 mg) prepared in the same manner as in the above Reference Example, and potato peptone (0.7 mg, 0.14 mg, and 0.028 mg). Although the repellent effect was not as good as potato peptone, it was found that, except for Kyokuto peptone, even an amount of 0.14 mg significantly repelled sweet potato root-knot nematodes (more than 70% in terms of relative amount).

[0046] In addition, on a different day from the above experiment, proteose peptone (manufactured by BD), tryptone (manufactured by Nakarai), and BD yeast extract (manufactured by BD) were used as samples as control ingredients, and the amounts of the control ingredients were changed to 0.7 mg, 0.14 mg, and 0.028 mg, respectively, and the same experiment as in Example 1 was carried out. The results are shown in FIG. 21. As a comparative sample, on the same day, an experiment similar to that in Example 1 was carried out using pure water (MilliQ) and CM (values ​​of 7.5 mg to 0.1 mg shown in FIG. 21) prepared in the same manner as in the above Reference Example. The repellent effect was confirmed for all control ingredients, and it was found that proteose peptone (manufactured by BD) and tryptone (manufactured by Nakarai) significantly repelled sweet potato root-knot nematodes even at an amount of 0.14 mg (relative amount exceeds 70%).

[0047] 2.Plant protection activity Next, the plant protecting activity of Lotus japonicus against Meloidogyne incognita using the eight types of control ingredients used in Examples 1 to 8 was examined as follows.

[0048] First, 0.1 ml of the sample containing histidine (control component) at a concentration of 5 mg / ml prepared in Experimental Example 1 was soaked into a piece of filter paper cut in half with a radius of 1 cm, and air-dried in a clean bench for 1 hour. As shown in Figure 12, three Lotus japonicus specimens were placed on an infection experiment plate at intervals of 35 mm, and the piece of filter paper was placed 2 mm from the root of the Lotus japonicus (sample No. 1) growing on the far left side. Approximately 50 nematodes were seeded 1 cm away from the tip of each Lotus japonicus root and left to stand at 23°C for 48 hours. The specimens were immersed in 3% antiformin for 3 minutes. The roots were thoroughly washed with water, placed in a well of a 6-well plate containing acidic fuchsin stock, and then heated in a thermostatic chamber at 90°C for 7 minutes. The specimens were then allowed to cool at room temperature for 10 minutes, immersed on a slide glass with acid-added glycerin spread over the entire surface, and left to stand overnight at room temperature. The stained nematodes were then crushed with a cover glass along with the roots of samples No. 1 to 3, and the number of infected nematodes was counted visually.

[0049] The infection rates of Meloidogyne in the roots of Lotus japonicus samples No. 1 to 3 are shown in the graph in Figure 13. In the control, the number of Meloidogyne indices was almost the same in all samples, but when 0.5 mg of histidine was present in the filter paper piece, the number of Meloidogyne indices in sample No. 1 was significantly reduced. This shows that Meloidogyne indices were prevented from invading the Lotus japonicus roots close to the filter paper piece.

[0050] A similar experiment on plant protection activity was carried out using a piece of filter paper impregnated with a 5 mg sample (CM) of the secretion of the cellular slime mold used in the above Reference Example. The results are also shown in the graph of FIG.

[0051] A similar experiment on plant protection activity was carried out using 0.5 mg each of cysteine, ornithine and lysine as the control ingredients. The results are shown in the graph in Figure 14. When these control ingredients were present on the filter paper pieces, the number of Meloidogyne incognita in sample No. 1 was significantly reduced, indicating that the presence of the control ingredients repelled Meloidogyne incognita from invading Lotus japonicus roots. A similar experiment was also carried out using filter paper pieces containing a 5 mg sample of cellular slime mold secretions. The results are also shown in the graph in Figure 14.

[0052] Similar plant protection activity experiments were conducted on the same day, but with the control ingredients changed to ascorbic acid and arginine, respectively. The results are shown in the graph in Figure 15. When these control ingredients were present on the filter paper pieces, the number of Meloidogyne incognita in sample No. 1 was significantly reduced, indicating that the presence of the control ingredients repelled the Meloidogyne incognita from invading the Lotus japonicus roots. A similar experiment was also conducted using filter paper pieces containing a 5 mg sample of cellular slime mold secretions. The results are also shown in the graph in Figure 15.

[0053] A similar experiment on plant protection activity was carried out using 4-hydroxyphenylacetic acid as the control ingredient. The results are shown in the graph in Figure 16. When the control ingredient was present on the filter paper piece, the number of Meloidogyne incognita in sample No. 1 was significantly reduced, indicating that the presence of the control ingredient repelled Meloidogyne incognita from invading Lotus japonicus roots. A similar experiment was also carried out using a filter paper piece containing a 5 mg sample of cellular slime mold secretions. The results are also shown in the graph in Figure 16.

[0054] A similar experiment on plant protection activity was conducted using glucosamine as the control ingredient. The results are shown in the graph in Figure 17. When the control ingredient was present on the filter paper piece, the number of Meloidogyne incognita in sample No. 1 was significantly reduced, indicating that the presence of the control ingredient repelled the Meloidogyne incognita from invading the Lotus japonicus roots. A similar experiment was also conducted using a filter paper piece containing a 5 mg sample of cellular slime mold secretions. The results are also shown in the graph in Figure 17. Note that the experimental results shown in Figures 13 to 17 were conducted on different days.

[0055] A similar experiment on plant protection activity was carried out using potato peptone, which was used in Example 9 as a control ingredient, as a sample. To examine the effective amount of potato peptone, the amount of potato peptone in the sample was changed to 2.5 mg, 0.5 mg, 0.1 mg, and 0.025 mg, respectively. The results are shown in Figure 22. When at least 0.1 mg of potato peptone was present on the filter paper piece, the number of root-knot nematodes in sample No. 1 was significantly reduced, indicating that the presence of potato peptone repelled the root-knot nematodes from invading the Lotus japonicus roots. In addition, a similar experiment was carried out using filter paper pieces soaked in sterilized water (DDW) and CM (3.5 mg). The results are also shown in the graph of Figure 22.

[0056] These experimental results show that spraying the control ingredient or a liquid containing it onto soil, etc., can effectively repel sweet potato root-knot nematodes that are present there or that are attempting to invade.

[0057] 3. Repellent effect of oligomers of pest control ingredients In Example 1, the effectiveness of the repellent effect of histidine against Meloidogyne incognita was confirmed, but in this example, the effect of a histidine oligomer (hexamer) was also confirmed in the same manner as in the previous example. The results are shown in Figure 18. It can be seen that even an amount of 0.005 mg of histidine oligomer repels Meloidogyne incognita. It is expected that the use of oligomers will make the control component less likely to decompose in soil.

[0058] Although the present invention has been specifically described above using examples, the present invention is not limited thereto, and includes various modifications, improvements, and alternatives and methods that can be made within the scope of the technical ideas described in the claims. In the above examples and comparative examples, the target of control is Meloidogyne incognita, but the control agent of the present invention has repellent activity not only against Meloidogyne incognita, but also against other root-knot nematodes including Meloidogyne niger. [Industrial Applicability]

[0059] The root-knot nematode control agent of the present invention is easily available and can effectively repel root-knot nematodes even in small amounts without causing damage to agricultural crops or living organisms. Therefore, the present invention can increase agricultural productivity while maintaining the safety of agricultural crops and workers, and is expected to make a significant contribution to the agricultural field.

Claims

1. A root-knot nematode control agent comprising at least one basic amino acid selected from the group consisting of histidine, ornithine, arginine and lysine.

2. The root-knot nematode control agent according to claim 1, characterized in that the basic amino acid is histidine.

3. The root-knot nematode control agent according to claim 1, characterized in that the basic amino acids include histidine, arginine and lysine.

4. The root-knot nematode control agent according to claim 3, further comprising cysteine.

5. 5. The root-knot nematode control agent according to claim 4, further comprising a peptone containing histidine, arginine, lysine and cysteine ​​as constituent components.

6. The root-knot nematode control agent according to claim 5, wherein the peptone is potato peptone.

7. A root-knot nematode control agent comprising at least one antioxidant component selected from the group consisting of cysteine, ascorbic acid, glucosamine and hydroxyphenylacetic acid.

8. The root-knot nematode control agent according to claim 7, characterized in that the antioxidant component is cysteine ​​or ascorbic acid.

9. The root-knot nematode control agent according to any one of claims 1 to 6, further comprising an inorganic or organic carrier, and the basic amino acid is supported on the inorganic or organic carrier.

10. The root-knot nematode control agent according to claim 7 or 8, further comprising an inorganic or organic carrier, and the antioxidant component is supported on the inorganic or organic carrier.

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