Ant control agents

Abstract

The present invention provides an ant control agent that can control ants without containing active ingredients made of organic compounds, has a simple composition, and is effective in any environment. [Solution] An ant control agent containing titanium dioxide with a primary particle size of 100 nm or less.

Description

Technical Field

[0001] The present invention generally relates to a control agent for sanitary pests and nuisance pests, and particularly relates to a control agent for ants.

Background Art

[0002] In recent years, damages caused by invasive ants such as the red imported fire ant and the Argentine ant have been reported both at home and abroad. Not only human damages such as residents being stung by the red imported fire ant and developing anaphylaxis after being stung, but also economic damages such as agricultural and livestock products being eaten, cows being stung and milk production decreasing, entering mechanical equipment and causing fires and power outages, building nests in houses and lands and reducing the value of real estate, and environmental damages such as eating chicks, insects, and plants and disturbing pollination and disrupting the balance of the ecosystem have also been reported.

[0003] Ants are social insects and act in groups. The reproductive ability of invasive ants that successfully establish themselves at the invasion site, including the red imported fire ant, is extremely high, and they form a large integrated colony with many queens. Since a single queen of the red imported fire ant lays 1,000 to 2,000 eggs a day and it is not uncommon for there to be thousands of queens in each colony, once an invasive ant colony is formed at the invasion site, it will multiply and spread in an instant, and it is extremely difficult to eradicate.

[0004] Conventionally, insecticides, repellents, and pheromone agents have been used for the control of invasive ants. As repellents, agents that emit odors disliked by ants are used. The pheromone agent aims to confuse ants, inhibit unity, and decline the nest by placing the same substance as the ant's trail pheromone. One of the inventors of the present application has also proposed a method and an agent for controlling Argentine ants by inducing the avoidance behavior of Argentine ants using a nestmate recognition pheromone (a pheromone substance for recognizing whether they are nestmates of the same nest) in Japanese Patent Application Laid-Open No. 2012-250938 (Patent Document 1).

[0005] Because the effects of these pesticides do not last long, it is necessary to continuously spray these pesticides, which contain numerous organic compounds, in order to prevent ant colonization. However, spraying insecticides temporarily reduces the number of sanitary and nuisance pests, as well as their natural enemies, which may create an environment where sanitary and nuisance pests can thrive in the long term. Furthermore, there are concerns that continuously spraying pesticides containing organic compounds over a long period of time may cause harm to human health or adversely affect other organisms.

[0006] Therefore, there is a growing demand for highly safe inorganic compound-based pest control agents. Furthermore, even when using insecticides and repellents made from inorganic compounds that have little impact on humans and the environment, continuous application requires enormous effort and cost. However, among inorganic compounds, titanium dioxide has a semi-permanent effect, so pest control agents using titanium dioxide are being proposed.

[0007] For example, Japanese Patent Publication No. 2008-133230 (Patent Document 2) describes a sanitary pest repellent that aims to enhance the persistence of the repellent effect through a synergistic effect between the oxidation-promoting effect of radical oxygen ions generated by highly crystalline titanium dioxide nanoparticles and the repellent effect of a sanitary pest repellent component. This repellent is either placed on the surface of crystalline titanium dioxide nanoparticles or uniformly distributed throughout the interior of the crystalline titanium dioxide nanoparticles.

[0008] Japanese Patent Publication No. 11-343209 (Patent Document 3) describes a method of controlling pests and diseases of plants growing under sunlight by applying a substance mainly composed of a photocatalyst to plants using methods such as spraying, dipping, etc.

[0009] Japanese Patent Publication No. 2004-323501 (Patent Document 4) describes the application of titanium dioxide to farmland as an antimicrobial and insecticidal agent. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2012-250938 [Patent Document 2] Japanese Patent Publication No. 2008-133230 [Patent Document 3] Japanese Patent Application Publication No. 11-343209 [Patent Document 4] Japanese Patent Publication No. 2004-323501 [Overview of the project] [Problems that the invention aims to solve]

[0011] However, the insect repellent for sanitary pests described in Patent Document 2 requires the combination of titanium dioxide and a repellent component, resulting in a complex manufacturing process.

[0012] The pest control agent and method described in Patent Document 3 control pests and diseases by utilizing the photocatalytic effect of the pest control agent when plants growing under sunlight receive sunlight. However, it does not consider preventing pests and diseases from attaching themselves to plants or preventing them from settling on plants.

[0013] The antibacterial and deodorizing agent described in Patent Document 4 is also intended for use in agricultural fields under sunlight, and does not take into account the prevention of the invasion and establishment of sanitary and nuisance pests such as ants in agricultural fields.

[0014] Therefore, the objective of this invention is to provide an ant control agent that can control ants without containing an active ingredient made of an organic compound, and that can exert its effect regardless of the environment with a simple configuration. [Means for solving the problem]

[0015] As a result of diligent research, the inventors have found that when titanium dioxide with a primary particle size of 100 nm or less is supplied at a low concentration in a specific area, ants enter the area but become lost, unable to form a trail, and are unable to cooperate with other ants to bring food back to the nest. Furthermore, they have found that when titanium dioxide with a primary particle size of 100 nm or less is supplied at a higher concentration in a specific area, ants avoid entering that area.

[0016] The inventors hypothesized that ants get lost because the photocatalytic properties of titanium dioxide affect the trail pheromones left behind by ants in the area. They believed that if ants could be prevented from recognizing these trail pheromones, they would be unable to build nests or bring food back to their nests, thus preventing ant colonization.

[0017] On the other hand, it is thought that ants avoid entering the area because the amount of powder adhering to their legs increases, making it difficult for them to easily brush it off, and thus they try to avoid the areas where the powder adheres. Microscopic observation revealed that titanium dioxide with a primary particle size exceeding 100 nm, such as 180 nm, hardly adheres to the gaps between the hairs on ants' legs, while titanium dioxide with a primary particle size of 100 nm or less easily adheres to the gaps between the hairs on ants' legs and to their bodies. Insect legs are covered with numerous diverse sensory hairs, which act as sensors for tactile information such as taste, smell, and ground texture. It is thought that insects avoid powder adhesion because keeping the hairs on their legs clean is necessary for them to accurately perceive their environment and act normally.

[0018] Based on the above findings, the ant control agent according to the present invention contains titanium dioxide with a primary particle size of 100 nm or less.

[0019] In this way, it is possible to provide an ant control agent that can control ants without containing active ingredients made of organic compounds, and that can exert its effect regardless of the environment with a simple composition.

Brief Description of the Drawings

[0020] [Figure 1] It is a diagram showing the change over time of the loss rate in Experiment 1 and Experiment 3 of Example 1 (3.125% by volume of titanium oxide in the mixed sand). [Figure 2] It is a diagram showing the change over time of the loss rate in Experiment 1 and Experiment 3 of Example 1 (5% by volume of titanium oxide in the mixed sand). [Figure 3] It is a diagram showing the change over time of the number of ants that invaded onto the dishes in Experiment 1 and Experiment 2 of Example 2. [Figure 4] It is a diagram showing the change over time of the number of ants that invaded onto the dishes in Experiment 1 and Experiment 2 of Example 3.

Modes for Carrying Out the Invention

[0021] Hereinafter, the ant repellent of the present invention will be described in detail with specific examples. Note that the present invention is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of the present invention.

[0022] The control agent for ants according to the present invention contains titanium oxide having a primary particle diameter of 100 nm or less. The crystal system of titanium oxide may be any of anatase type, rutile type, and brookite type, and it is preferable to include the anatase type. The primary particle diameter is the equivalent circle diameter obtained by photographing the particles of titanium oxide with a transmission electron microscope (the number of particles to be photographed is 1,000 or more) and performing image processing on the individual photographed particles with an image analysis type particle size distribution measuring device.

[0023] The control agent for ants according to the present invention can control ants even if it does not contain an ant repellent composed of an organic compound. Considering the influence on the human body and the environment, it is preferable that the control agent for ants does not contain a repellent composed of an organic compound.

[0024] In the control agent for ants according to the present invention, the specific surface area of titanium oxide is preferably 30 - 300 m 2 / g.

[0025] In the ant control agent according to the present invention, the bulk density of titanium dioxide is 0.1 to 0.4 g / cm³. 3 It is preferable that this be the case.

[0026] The ant control agent according to the present invention preferably contains 3% or more by volume of titanium dioxide, and more preferably 6% or more by volume.

[0027] The ant control agent according to the present invention preferably contains calcium carbonate or calcium sulfate, and more preferably contains coral sand. Coral is mainly composed of calcium carbonate. Ants are known to dislike walking on lime, which is also mainly composed of calcium carbonate, or on lines drawn with chalk, which is mainly composed of calcium carbonate and calcium sulfate. Coral sand is granular and heavier than lime or chalk powder. By attaching titanium dioxide to coral sand, the weight of the coral makes it less likely to be washed away by rain or wind. In addition, since ants dislike walking on coral granules in the first place, the ant control effect can be further enhanced. When mixing titanium dioxide and coral sand, it is preferable to use an adhesive or glue so that the titanium dioxide adheres to the coral sand.

[0028] When applying the ant control agent according to the present invention, it can be sprayed or placed in a manner that surrounds the area where ants are to be prevented from entering. Furthermore, the ant control agent according to the present invention can be sprayed or placed in a manner that surrounds the area where ants are to be prevented from establishing themselves. The ant control agent according to the present invention is not limited, but is preferably sprayed or placed in a width of 15 mm or more, and more preferably in a width of 100 mm or more. [Examples]

[0029] The present invention will be explained in more detail by showing specific manufacturing examples and test results of the ant repellent.

[0030] <Example 1> It is known that when ants find food, they release trail pheromones on their way back to the nest. If you place food and ants at the exit (goal) of a plastic maze, and the ants carry the food back from the exit to the entrance, then ants that enter from the entrance afterward can easily follow the trail pheromones and find the food at the exit.

[0031] Here, the maze floor was prepared using (1) neutral sand collected from the experimental site (control experiment), (2) alkaline coral sand with the same components as lime, which ants dislike (reference experiment), and (3) a mixture of neutral sand and titanium dioxide collected from the experimental site. After the first ants carried food from the exit to the entrance of the maze, the behavior of ants entering from the entrance was observed.

[0032] The maze was a plastic toy maze, a square with sides of 8.5 cm. It had one entrance, and from the entrance to the exit (the goal where the food was placed), there was one shortest route and two longer routes, for a total of three routes.

[0033] (Experiment 1) Neutral sand collected from the experimental site was spread on the floor of the maze. Honey was dripped at the exit (goal) of the maze. Outside the maze, about 10 cm away, potato chips (seaweed and salt flavor) were placed on the ground near the nest of the brown ant. When the ants formed a line, about 5 ants were picked up along with the potato chips and moved to the exit (goal) of the maze. The maze was covered with a glass plate. The inside of the maze was photographed.

[0034] Ants placed in the goal along with a bag of potato chips walked towards the entrance of the maze, exited the maze, and returned to their nest. One hour after filming began, ants that entered the maze from the entrance but could not reach the exit (goal) via the shortest route were identified as "lost." Every five minutes, the number of ants on the maze floor was measured, and the percentage of ants identified as lost, i.e., ants in positions other than the shortest route, was calculated as the "lost rate." If there were no ants in the maze or at the exit (goal) after one hour, the experiment was retried up to three times, and observation continued for a total of four hours.

[0035] Between 1 hour and 2 hours and 20 minutes after filming began, 320 ants had entered the maze. Most of the ants followed the shortest route without hesitation, and a line of ants quickly formed.

[0036] (Experiment 2) The behavior of ants was observed in the same manner as in Experiment 1, except that coral sand was used instead of the neutral sand used in Experiment 1. The coral sand was granular with a diameter of approximately 5 mm.

[0037] For the first four hours after filming began, not a single ant had entered the maze.

[0038] (Experiment 3) The behavior of ants was observed in the same manner as in Experiment 1, except that a mixed sand containing titanium dioxide was used instead of the neutral sand from Experiment 1. The titanium dioxide used was Teika Co., Ltd. (AMT-100, primary particle size: 6 nm). The amounts of titanium dioxide in the mixed sand were 3.125 vol%, 5 vol%, 6.25 vol%, and 12.5 vol%. The experiment was repeated on different days for each titanium dioxide concentration. If there were no ants in the maze or at the exit (goal) after 1 hour, the experiment was retried up to 3 times, and observation continued for a total of 4 hours. The results are shown in Table 1.

[0039] [Table 1]

[0040] Figures 1 and 2 show the time evolution of the ant-getting-lost rate in Experiment 1 and Experiment 3 (3.125 vol% or 5 vol% titanium dioxide in the mixed sand). Note that no ants entered the maze in Experiment 2, so the ant-getting rate was not calculated.

[0041] As shown in Figures 1 and 2, the rate of ants getting lost was higher in mixed sand compared to sand without titanium dioxide. There was no significant difference in the rate of ants getting lost between mixed sand with a titanium dioxide content of 3.125 vol% and 5 vol%. However, the number of ants that entered the maze was more than 30% less in the 5 vol% mixture compared to the 3.125 vol% mixture.

[0042] When the titanium dioxide content in the mixed sand was 6.25% by volume, more ants hesitated to enter the maze from the entrance and turned back without entering the maze compared to when the mixed sand contained 5% by volume of titanium dioxide.

[0043] When the titanium dioxide content in the mixed sand was 25% by volume and 50% by volume, ants that entered the maze from the entrance wandered around aimlessly and were hardly able to reach the food at the exit (goal). No ants followed the return route (the path from the exit to the entrance) of the ants that reached the exit. No ants walked from the entrance to the exit without backtracking, regardless of whether they took the shortest or longest route; only ants that wandered around aimlessly in the maze for a long time before luckily reaching the exit. In addition, many ants hesitated at the entrance of the maze and turned back.

[0044] From the above experiments, it was found that even a small amount of titanium dioxide in the mixed sand is effective in controlling ants. When the titanium dioxide content in the mixed sand is relatively low, ants enter the maze but get lost. It is thought that by placing even a small amount of titanium dioxide around nests and feeding areas, it is possible to disorient ants and prevent them from forming or establishing nests.

[0045] Furthermore, it was found that when the titanium dioxide content in the mixed sand is high, ants dislike entering the maze altogether, similar to coral sand. It is considered effective to place mixed sand with a titanium dioxide content of 6.25% by volume or higher in areas where ant intrusion needs to be prevented.

[0046] <Example 2> We observed the behavior of ants when titanium dioxide was present on the substrate leading to the food source, and when it was not, under conditions where ants can find food by scent rather than trail pheromones. Crushed dried shrimp, a food source for the brown ant, was used.

[0047] (Experiment 1) A thin plastic plate (a beverage cup lid) with a diameter of 12 cm was covered with neutral sand (control experiment) collected at the experimental site, without any breaks along the circumference, from at least 15 mm inward from the edge. Crushed dried shrimp and shrimp powder, which had been crushed immediately before the experiment, were attached to the sand in the center of the plate using double-sided tape.

[0048] (Experiment 2) The experiment was conducted in the same manner as in Experiment 1, except that the neutral sand used in Experiment 1 was replaced with a mixed sand (6.25% by volume of titanium dioxide) made by adding titanium dioxide to neutral sand collected at the experimental site.

[0049] The dishes from Experiment 1 and Experiment 2 were placed side by side on the ground, and the behavior of the ants was observed every 5 minutes.

[0050] Figure 3 shows the change in the number of ants that entered the dish in Experiment 1 and Experiment 2 over time. As shown in Figure 3, throughout the entire time period from the start to the end of the experiment, more ants entered the dish in Experiment 1 than in Experiment 2. In Experiment 1, some ants moved vigorously as if excited after the start of the experiment, and a line quickly formed. 215 ants entered the dish in Experiment 1. In Experiment 2, many ants clearly hesitated about whether to proceed towards the food and turned back. Some ants hesitated only at the beginning, but after a while entered the dish and reached the food. The degree to which ants disliked the mixed sand containing titanium dioxide seemed to vary from individual to individual. 80 ants entered the dish in Experiment 2.

[0051] <Example 3> In this example, the width of the mixed sand containing titanium dioxide was increased compared to Example 2, and the behavior of the ants was observed. Crushed dried shrimp, which are the food source for the brown wrinkled ant, was used.

[0052] (Experiment 1) A commercially available neutral river sand was placed in the center of a large paper plate, and crushed dried shrimp and shrimp powder, prepared immediately before the experiment, were placed on top of the river sand as bait. A toilet paper roll was placed upright in the center of the paper plate to create a wall around the bait. From the outside of the toilet paper roll outwards in the radial direction of the paper plate, up to 100 mm, the same commercially available neutral river sand (control experiment) was spread without breaks along the circumference. The neutrality was confirmed with BTB solution. The river sand had a diameter of 1 mm or less.

[0053] (Experiment 2) The experiment was conducted in the same manner as in Experiment 1, except that the neutral river sand on the outside of the toilet paper roll core was replaced with a mixed sand containing titanium dioxide (6.25 vol%). The same river sand as in Experiment 1, but without titanium dioxide, was placed inside the toilet paper roll core.

[0054] The dishes from Experiment 1 and Experiment 2 were placed side by side on the ground, and the behavior of the ants was observed every 5 minutes.

[0055] Figure 4 shows the change in the number of ants that entered the dish over time in Experiment 1 and Experiment 2. As shown in Figure 4, in Experiment 1, the number of ants entering the dish increased over time, but in Experiment 2, there were hardly any ants that entered the dish. In Experiment 1, some ants moved vigorously as if excited after the experiment started, and a line quickly formed. 502 ants entered the dish in Experiment 1. In Experiment 2, many ants circled the outer edge of the mixed sand, were unable to enter the sand, and then gave up and left. Some ants reluctantly entered the mixed sand, but repeatedly turned back after advancing only 1-5 cm. Exceptionally, some ants reached the food, but other ants did not follow, and no line of ants formed. 16 ants entered the dish in Experiment 2.

[0056] <Example 4> A petri dish with an inner diameter of 9.5 cm was covered with titanium dioxide powder on its entire bottom surface, and ant feed was placed in the center. This petri dish was placed inside a large aluminum case with a lid, and 50 ants were released into the case. The petri dish was observed for one hour immediately after the ants were released, and the number of times the ants stepped onto the powder covering the petri dish was counted. All titanium dioxide used was manufactured by Teika Co., Ltd.

[0057] Table 2 shows the results when the Japanese ant (Crematogaster) was used as the ant species. The ant-repellent effect was rated as follows: "◎" if the number of times the ant stepped in was less than 4, "○" if the number of times the ant stepped in was 4 or more but less than 8, and "×" if the number of times the ant stepped in was 8 or more.

[0058] [Table 2]

[0059] Based on these results, it was confirmed that areas covered with titanium dioxide particles with a primary particle size of 100 nm or less have an ant-repellent effect.

[0060] Next, the photodegradation and adsorption effects of titanium dioxide on methyl 6-methyl salicylate (M6M), a trail pheromone of the ant *Lasius niger*, were evaluated. In Examples 5-8 below, chemically synthesized M6M was used.

[0061] <Example 5> We investigated whether titanium dioxide adsorbs M6M. Titanium dioxide AMT-100 (powder 1-1 in Table 2), manufactured by Teika Co., Ltd., was used. Five glass tubes (2 mL in volume) were prepared, and a small magnetic stirrer bar was placed in each. Next, different amounts of powder 1-1 were added to each glass tube, followed by 0.5 mL of M6M hexane solution (10 ng / μL, containing C14 (1 ng / μL)). The tubes were covered with aluminum foil and stirred (500 rpm) under light shielding. Stirring was stopped at 15-minute intervals, 10 μL of the supernatant was taken and placed in a vial for analysis by gas chromatography. This was repeated four times, with a total of four samples taken up to 60 minutes later. The measured M6M / C14 peak area ratios are shown in Table 3.

[0062] [Table 3]

[0063] The results shown in Table 3 indicate that the greater the amount of powder 1-1, the lower the concentration of M6M after stirring. In other words, it was found that powder 1-1 adsorbs M6M.

[0064] Furthermore, the concentration of M6M did not change even after stirring for more than 15 minutes. This suggests that powder 1-1 adsorbs M6M quickly, adsorbing the maximum amount of M6M it can adsorb within 15 minutes, and then does not desorb any further.

[0065] <Example 6> The decomposition of M6M by powder 1-1 was investigated. 0.2 g of silica gel (substrate) coated with M6M was weighed into three small glass petri dishes to form a test group, a light-shielding test group, and a control group. In the test group, 1 mg of powder 1-1 was added to 0.2 g of substrate (0.5 mass%). In the light-shielding test group, 1 mg of powder 1-1 was added to 0.2 g of substrate (0.5 mass%), and the mixture was covered with aluminum foil to shield it from light. In the control group, only 0.2 g of substrate was used, with no powder 1-1 added.

[0066] Samples were taken at 0 hours before exposure to direct sunlight, and then the petri dishes were placed in direct sunlight. Approximately 10 mg was taken from each petri dish at 15 minutes, 30 minutes, 1 hour, and 2 hours after 13:00 and weighed. The samples were extracted with an ethyl acetate solution containing an internal standard substance (C14, 1 ng / μL) (ultrasonic irradiation for 1 minute, then left to stand in the dark until analysis), and the extracts were analyzed by gas chromatography. The illuminance at the installation location is shown in Table 4, and the measured M6M / C14 peak area ratio is shown in Table 5.

[0067] [Table 4]

[0068] [Table 5]

[0069] As shown in Table 5, in the test plot, the peak area ratio of M6M / C14 decreased compared to 0 hours later: 43% at 15 minutes, 27% at 30 minutes, 2.9% at 1 hour, and 0.7% at 2 hours. On the other hand, in the light-shielding test plot, 76% of M6M remained after 1 hour, and 59% remained even after 2 hours.

[0070] <Example 7> We investigated whether titanium dioxide adsorbs M6M. Titanium dioxide JR (powder 6) manufactured by Teika Co., Ltd. was used as the titanium dioxide. Five glass tubes (2 mL volume) were prepared, and a small magnetic stirrer bar was placed in each. Next, different amounts of powder 6 were added to each glass tube, and then 0.5 mL of M6M hexane solution (10 ng / μL, containing C14 (1 ng / μL)) was added to each. The tubes were covered with aluminum foil and stirred (500 rpm) under light shielding. Stirring was stopped at 15-minute intervals, 10 μL of the supernatant was taken and placed in a vial, and 1 μL of this supernatant was analyzed by gas chromatography. This was repeated four times, and a total of four samples were taken up to 60 minutes later. The measured M6M / C14 peak area ratios are shown in Table 6.

[0071] [Table 6]

[0072] The results shown in Table 6 indicate that powder 6 hardly adsorbs M6M.

[0073] <Comparison of experimental results> The time-dependent changes in the adsorption amount of M6M by powder 1-1 or powder 6 were compared. Tables 7 and 8 show the normalized peak area ratios for each powder amount and stirring time, with the M6M / C14 peak area ratio at 0.0 mg of powder set to 1.00.

[0074] [Table 7]

[0075] [Table 8]

[0076] <Example 8> The differences in the decomposition of M6M depending on the type of titanium dioxide were investigated. 0.2 g of silica gel (substrate) coated with M6M was weighed into two small glass petri dishes and designated as Test Group A and Test Group B. In Test Group A, 1 mg of titanium dioxide powder 1-1 was added to 0.2 g of the substrate (0.5 mass%). In Test Group B, 1 mg of titanium dioxide powder 6 was added to 0.2 g of the substrate (0.5 mass%).

[0077] Samples were taken at time 0, before exposure to direct sunlight, and then the petri dishes were placed in direct sunlight. Approximately 10 mg was taken from each petri dish at 15 minutes, 30 minutes, 1 hour, and 2 hours after 13:00 and weighed. The samples were extracted with an ethyl acetate solution containing an internal standard substance (C14, 1 ng / μL) (ultrasonic irradiation for 1 minute, then left to stand in the dark until analysis), and the extracts were analyzed by gas chromatography. The illuminance at the installation location is shown in Table 9, and the measured M6M / C14 peak area ratio is shown in Table 10. Note that direct sunlight was no longer present after 16:00.

[0078] [Table 9]

[0079] [Table 10]

[0080] Table 11 shows the normalized peak area ratios for each powder and each elapsed time, with the M6M / C14 peak area ratio at 0 hours in Table 10 set to 1.00.

[0081] [Table 11]

[0082] Powder 1-1 showed higher photocatalytic activity than powder 6 in decomposing M6M.

[0083] The embodiments and examples disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description and includes all variations in the meaning and scope equivalent to the claims.

Claims

1. An ant control agent containing titanium dioxide with a primary particle size of 100 nm or less.

2. The ant control agent according to claim 1, wherein the titanium dioxide is of the anatase type.

3. An ant control agent according to claim 1, which does not contain an ant repellent made of an organic compound.

4. The specific surface area of ​​the aforementioned titanium oxide is 30 to 300 m². ２ An ant control agent according to claim 1, wherein the concentration is / g.

5. The bulk density of the titanium dioxide is 0.1 to 0.4 g / cm³. ３ The ant control agent according to claim 1.

6. An ant control agent according to any one of claims 1 to 5, comprising 3% by volume or more of the aforementioned titanium dioxide.

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