Low-toxicity long-acting pine wood nematode disease trunk injection agent and preparation method thereof

Abstract

The invention relates to the technical field of pine wood nematode diseases, in particular to a low-toxicity long-acting pine wood nematode disease trunk injection agent and a preparation method thereof. The method comprises the following steps: 1, preparing raw materials; 2, mixing copper sulfate and a mixed solvent; step 3, preparing a trunk injection agent; according to the low-toxicity long-acting pine wood nematode disease trunk injection agent and the preparation method thereof, through the preparation of the emamectin benzoate microemulsion, the copper sulfate and the mixed solvent, the concentration of the copper sulfate is effectively controlled, poison to plants is avoided while the pine wood nematode disease is strongly killed, and the survival rate of the pine wood nematode disease is increased. Copper ions in the copper sulfate and the emamectin benzoate have a synergistic effect, so that the high toxicity to the pine wood nematodes can be increased, catabolism of emamectin can be slowed down, the lasting period is greatly prolonged to 5 years or above, the pine wood nematode killing rate reaches 99% or above, the dosage and the application frequency are reduced, the prevention and treatment cost is reduced, and the prevention and treatment effect is good. Therefore, the good balance between the prevention and control effect and the safety is realized.

Description

Technical Field

[0001] The invention relates to the technical field of pine wood nematode disease prevention and treatment, in particular to a low-toxic and long-acting pine wood nematode disease dry injection agent and a preparation method thereof. Background Art

[0002] Pine wilt disease, as the number one pest in the current forestry industry, is like the "cancer" of pine trees. It has the characteristics of rapid onset, rapid death, and rapid spread. It has caused huge ecological damage and serious economic losses to pine forests. It has become the quarantine and key prevention and control target in many countries. It is currently spreading into a disaster in many areas of my country.

[0003] In the treatment of pine wood nematode disease, there are quarantine, removal of infected trees, aircraft spraying to disinfect the vector insect pine brown alternator, and injection (dry) control. Among them, injection control is a preventive measure with high cost, mainly used in the protection of pine forests in important areas, key scenic spots, and scenic forests. One of the important reasons why it is difficult to apply on a large scale is that modern organic pesticides have low residue requirements. For example, pine wood nematode injection agents represented by avermectin are highly toxic but easily metabolized and have a short lasting effect. To extend the lasting effect, either increase the amount of application or repeat the application, which increases the difficulty and cost of prevention and control; taking a 30cm breast diameter Masson pine as an example, 3ml of 5% avermectin is injected into the stem per centimeter of breast diameter (the amount recommended by the manufacturer of existing products), and the half-life is calculated as 7 days. After 8 weeks (only two months), the residual concentration decays to below LC50. If 6 ml is injected into the stem for every cm of breast diameter (double the amount recommended by the manufacturer of existing products), the residual concentration will decay to below LC50 after 9 weeks. It can be seen that avermectin has a short half-life and rapid metabolism, and a short effective period. Although the effective period can be extended by increasing the application rate, the cost is very high.

[0004] However, copper ions are highly toxic to pine wood nematodes. In the toxicity ranking of metal ions, copper > lead > chromium, etc., and it is not easily metabolized in organisms. But when the concentration of copper ions is too high, it will cause serious harm to plants, directly interfere with the normal physiological functions of trees, and inhibit tree growth. In addition, in order to strictly avoid plant poisoning, the concentration of copper ions must be limited. At this safe concentration, the efficiency of disinfecting pine wood nematodes will be greatly reduced, and it will be difficult to control the spread and harm of pine wood nematodes, making it difficult to effectively prevent and control pine wood nematodes while ensuring plant safety. Summary of the invention

[0005] The object of the present invention is to provide a low-toxic and long-acting pine wood nematode injection agent and a preparation method thereof, which can avoid the insufficient disinfecting efficiency of copper ions due to concentration limitation when used alone, so as to balance the relationship between prevention and control effect and safety, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, on the one hand, the present invention provides a method for preparing a low-toxic and long-acting pine wood nematode injection agent, comprising the following steps: S1. Prepare raw materials: avermectin benzoate microemulsion, copper sulfate and miscible solvent; S2. Mixing copper sulfate and miscible solvent: Pour copper sulfate into the miscible solvent placed in the stirring device, turn on the stirring device to stir, and form a mixed solution; S3. Preparation of dry injection: adding the mixed solution into the stirring container to which the emamectin benzoate microemulsion has been added through a graduated separatory funnel, turning on the stirring function of the stirring container to stir the mixture, so that the three are fully mixed and uniformly obtained to obtain the emamectin benzoate-copper mixture dry injection; S4. Packaging: Put the prepared dry injection agent into a 50ml long-beak bottle. After filling, seal it with a bottle cap with good sealing performance, label it with product information, and place it in a cool, dry, well-ventilated place where children and unauthorized personnel cannot easily reach it for use; As a further improvement of the technical solution, in S1, the avermectin benzoate microemulsion adopts a commercial pesticide containing 2%-5% of avermectin.

[0007] As a further improvement of the technical solution, in S1, the miscible solvent is a 70% disodium ethylenediaminetetraacetic acid solution; In S2, the speed of copper sulfate pouring is 0.3s / g-0.8s / g; In S2, the stirring speed of the stirring device is 300r / min-500r / min; In S2, the stirring time is 10 min-15 min; In S3, the mixed solution is added at a rate of 1 mL / min-5 mL / min; In S3, the stirring speed of the stirring container is 200r / min-400r / min; In S5, the amount of the injection agent injected into the pine tree is 1 cm / ml based on the pine tree's diameter at breast height.

[0008] On the other hand, the present invention provides a low-toxic and long-acting dry injection agent for pine wood nematode disease prepared by any of the preparation methods described above, comprising the following raw materials in percentage by weight: Emamectin benzoate microemulsion: 80%-94% of the dry injection weight; Copper sulfate: 1%-5% of the weight of the dry injection agent; Miscible agent: 5%-15% of the dry injection agent by weight.

[0009] Compared with the prior art, the present invention has the following beneficial effects: 1. In the low-toxic and long-acting dry injection agent for pine wood nematode disease and its preparation method, the concentration of copper sulfate is effectively controlled by preparing avermectin benzoate microemulsion, copper sulfate and miscible solvent, which can effectively disinfect pine wood nematode disease while avoiding poisoning to plants. In addition, the copper ions in copper sulfate act synergistically with avermectin benzoate, which can increase the high toxicity to pine wood nematodes and slow down the decomposition and metabolism of avermectin, thereby greatly extending the effective period to more than 5 years, and the pine wood nematode killing rate reaches more than 99%, reducing the amount of medicine used and the number of times of application, reducing the prevention and control costs, and being economical and efficient in pine forest protection, thereby achieving a good balance between prevention and control effect and safety.

[0010] 2. The low-toxic and long-acting pine wood nematode injection agent and its preparation method include avermectin benzoate-copper combination injection agent, which can effectively kill pine wood nematodes and also has a killing effect on pine beetles, blocking the transmission route of pine wood nematode disease from the source and providing comprehensive protection for pine forest ecosystems. In addition, the injection agent has multifunctional uses. After being diluted 200-1000 times, it can be used for spraying, sprinkling, coating, and dipping for pest control of pine wood nematode diseased wood, thereby improving the applicability and flexibility of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The present invention is a flowchart of the preparation method of the low-toxic and long-acting pine wood nematode dry injection agent. DETAILED DESCRIPTION

[0012] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0013] The embodiment of the present invention provides a toxic and long-acting dry injection agent for pine wood nematode disease, comprising the following raw materials in percentage by weight: Emamectin benzoate microemulsion: accounting for 80%-94% of the weight of the dry injection agent; Emamectin benzoate microemulsion uses commercial pesticides containing 2%-5% of emamectin; Copper sulfate: accounts for 1%-5% of the weight of the dry injection agent. Copper sulfate should be of high purity, free of agglomerates and obvious impurities. Miscible solvent: accounts for 5%-15% of the weight of the dry injection agent; the miscible solvent adopts a 70% concentration of disodium ethylenediaminetetraacetic acid solution.

[0014] according to Figure 1As shown, the embodiment of the present invention also provides a preparation method for preparing the above-mentioned low-toxic and long-acting pine wood nematode injection agent, comprising the following steps: Step 1: prepare raw materials: avermectin benzoate microemulsion, copper sulfate and miscible solvent.

[0015] Step 2, mixing copper sulfate and miscible agent: copper sulfate is poured into the miscible agent placed in the stirring device, and the speed of copper sulfate pouring is 0.3s / g-0.8s / g, which can avoid copper sulfate powder from agglomerating in the miscible agent and prevent the poured copper sulfate solution from splashing. The stirring device is turned on for stirring, and the stirring speed of the stirring device is 300r / min-500r / min. The stirring time is 10min-15min. During the stirring process, the dissolution of copper sulfate needs to be closely observed to ensure that it is completely dissolved and evenly mixed with the miscible agent to form a mixed solution.

[0016] Step 3. Prepare the dry injection agent: add the mixed solution into the stirring container to which the avermectin benzoate microemulsion has been added through a graduated separatory funnel. The speed of adding the mixed solution is 1mL / min-5mL / min, which can enable the mixed solution to be added to the stirring container slowly and steadily to prevent splashing caused by liquid impact or excessive local concentration from affecting the mixing effect. The stirring container should have good sealing and corrosion resistance to prevent splashing of the solution or chemical reaction with the container during the stirring process. Turn on the stirring function of the stirring container for stirring. The stirring speed of the stirring container is 200r / min-400r / min. The stirring time is 20min-30min. The three are fully mixed to obtain the avermectin benzoate-copper mixture dry injection agent.

[0017] Step 4. Packaging: Pour the prepared dry injection agent into a 50ml long-beak bottle. During the filling process, ensure that there is no residual solution at the bottle mouth to avoid contaminating the bottle body and the external environment. After filling, use a bottle cap with good sealing performance to seal it and label the product information. The product information should at least include the product name, ingredients, preparation date and expiration date. Place it in a cool, dry, well-ventilated place where children and unauthorized personnel cannot easily reach it for use.

[0018] According to the above configuration method, the avermectin benzoate-copper combination injection agent is obtained. When using the injection agent, choose sunny and relatively stable weather in winter to operate, and avoid applying it under adverse weather conditions such as rain, snow, strong wind or extremely low temperature. Use a punching tool to drill holes at the height of the pine tree's diameter at breast height. The hole diameter is 6cm and the hole depth is 6-8cm. During the drilling process, pay attention to keep the drilling direction perpendicular to the tree trunk to avoid tilting or bending the hole. After the drilling is completed, use a clean brush or air blowing device to clean the wood chips and dust in the hole. Then, insert the long-beak bottle containing the injection agent into the hole, ensure that the long-beak bottle fits tightly against the hole wall without obvious gaps, squeeze the long-beak bottle to inject the injection agent into the pine tree from the long-beak mouth, and the amount of the injection agent injected into the pine tree is based on 1cm / ml of the pine tree's diameter at breast height to complete the application of the injection agent.

[0019] In the present invention, copper sulfate is first mixed with a miscible solvent, which not only enables copper sulfate to be fully dissolved and evenly dispersed in the miscible solvent, thereby avoiding adverse effects on subsequent mixing due to agglomeration or local uneven concentration, but also allows the mixed solution to be mixed with an emamectin benzoate microemulsion. By controlling the ratio of each raw material and the speed, time and stirring conditions during mixing, the fusion effect between the three components can be effectively improved, thereby making the texture of the emamectin benzoate-copper mixture dry injection uniform and the performance stable.

[0020] Among them, avermectin benzoate is combined with copper sulfate for a secondary reaction. The reaction mechanism is that the copper ions in copper sulfate can act synergistically with avermectin benzoate. On the one hand, copper ions themselves are highly toxic to pine wood nematodes and can directly act on nematodes. On the other hand, after combining with avermectin benzoate, it can slow down the decomposition and metabolism of avermectin, thereby prolonging the effective period of the dry injection agent, and can increase the prevention and control effect on pine wood nematode disease. Moreover, at the appropriate concentration, it can not only ensure the efficient killing of pine wood nematodes, but also reduce the toxic effects on pine trees, thereby improving the safety and effectiveness of prevention and control.

[0021] Through the preparation of avermectin benzoate microemulsion, copper sulfate and miscible solvent, the concentration of copper sulfate is effectively controlled, which can effectively disinfect pine wood nematode disease while avoiding poisoning to plants. In addition, the copper ions in copper sulfate act synergistically with avermectin benzoate, which can increase the high toxicity to pine wood nematodes and slow down the decomposition and metabolism of avermectin, thereby greatly extending the effective period to more than 5 years. The pine wood nematode killing rate reaches more than 99%, reducing the amount of medicine used and the number of applications, reducing the cost of prevention and control, and being economical and efficient in pine forest protection, thus achieving a good balance between prevention and control effect and safety.

[0022] Emamectin benzoate-copper combination stem injection can effectively kill pine wood nematodes and also has a killing effect on pine beetles, blocking the transmission route of pine wood nematode disease from the source and providing comprehensive protection for pine forest ecosystems. In addition, the stem injection agent has multi-functional uses. After being diluted 200-1000 times, it can be used for spraying, sprinkling, coating, and dipping for pest control of pine wood nematode-infected wood, thereby improving the applicability and flexibility of the product.

[0023] According to different raw material dosages, the low-toxic and long-acting pine wood nematode dry injection agent provided by the present invention is further illustrated by the following specific examples.

[0024] Example 1 Raw material dosage: Emamectin benzoate microemulsion: take 94% (weight ratio), the emamectin content in the microemulsion is 2%; copper sulfate: take 1% (weight ratio), use a product with a purity of 99%, no lumps, and no obvious impurities; miscible solvent: take 5% (weight ratio), which is a 70% concentration of disodium ethylenediaminetetraacetic acid solution.

[0025] Preparation process: Step 2: Pour copper sulfate into the miscible solvent at a speed of 0.8 s / g, set the stirring device speed to 500 r / min, and stir for 10 min to form a mixed solution; Step 3: Add the mixed solution into the stirring container where the avermectin benzoate microemulsion is located through a separatory funnel at a speed of 1 mL / min, set the stirring container speed to 400 r / min, stir for 20 minutes, and obtain a dry injection agent.

[0026] Performance Test: The trunk injection agent is used for the prevention and control of pine wood nematode disease. In winter, the trunk of pine trees with a breast diameter of 30 cm is injected at a dosage of 1 cm / ml. It is observed that in the first two years after the injection, the pine trees grew well, the infection rate of pine wood nematode disease was significantly reduced, and the killing rate of pine wood nematodes reached more than 99%. In the subsequent 3-5 years, through regular inspections, the occurrence of pine wood nematode disease can still be effectively controlled, and no toxicity to the pine trees has been found.

[0027] Example 2 Raw material dosage: Emamectin benzoate microemulsion: take 90% (weight ratio), the emamectin content in the microemulsion is 3%; copper sulfate: take 4% (weight ratio), the purity is 98%, no agglomeration, no obvious impurities; miscible solvent: take 6% (weight ratio), which is 70% disodium ethylenediaminetetraacetic acid solution.

[0028] Preparation process: Step 2: Pour copper sulfate into the miscible solvent at a speed of 0.6 s / g, stir at a speed of 400 r / min, and stir for 12 min to obtain a mixed solution; Step 3: The mixed solution is added into the stirring container where the avermectin benzoate microemulsion is located at a speed of 3 mL / min, the stirring container speed is set to 300 r / min, and stirred for 25 minutes to obtain a dry injection agent.

[0029] Performance Test: Pine trees with a breast diameter of 40 cm were injected with pesticides for prevention and control, and continuous observation was carried out after injection. In the first year, the color of the pine needles was normal, and no typical symptoms of pine wilt disease appeared. In the third year, tests found that the killing rate of pine wilt was still maintained at more than 99%, the growth of pine trees was not significantly affected, and the effective period was significantly extended.

[0030] Example 3 Raw material dosage: Emamectin benzoate microemulsion: take 85% (weight ratio), the emamectin content in the microemulsion is 4%; copper sulfate: take 3% (weight ratio), the purity is 99.5%, no agglomeration, no obvious impurities; miscible solvent: take 12% (weight ratio), which is 70% disodium ethylenediaminetetraacetic acid solution.

[0031] Preparation process: Step 2: Pour copper sulfate into the miscible solvent at a speed of 0.5 s / g, set the stirring device speed to 350 r / min, and stir for 14 min to form a mixed solution; Step 3: The mixed solution is added into the stirring container where the avermectin benzoate microemulsion is located at a speed of 4 mL / min, the stirring container speed is 250 r / min, and the stirring is performed for 28 minutes to prepare a dry injection agent.

[0032] Performance Test: A forest slightly infected with pine wilt disease was selected, and the pine trees with an average breast diameter of 35 cm were treated with trunk injection. Within five years after the injection, through regular inspection of the pine trees, it was found that the condition of pine wilt disease was effectively controlled, the kill rate was maintained at more than 99%, the trees were growing well, and there was no plant poisoning caused by excessive concentration of the trunk injection agent. At the same time, the number of pine beetles was effectively reduced.

[0033] Example 4 Raw material dosage: Emamectin benzoate microemulsion: take 80% (weight ratio), the emamectin content in the microemulsion is 5%; copper sulfate: take 5% (weight ratio), the purity is 99%, no agglomeration, no obvious impurities; miscible solvent: take 15% (weight ratio), which is 70% disodium ethylenediaminetetraacetic acid solution.

[0034] Preparation process: Step 2: Pour copper sulfate into the miscible solvent at a speed of 0.3s / g, stir at a speed of 300r / min, and stir for 15min to obtain a mixed solution; Step 3: The mixed solution is added into the stirring container where the avermectin benzoate microemulsion is located at a speed of 5 mL / min, the stirring container speed is set to 200 r / min, and stirred for 30 minutes to prepare a dry injection agent.

[0035] Performance Test: The pine trees (DBH of about 25-30cm) in a key scenic area were injected with the drug for prevention and control. After long-term observation, the pine trees did not die due to pine wilt disease within five years, and the killing rate of pine wilt remained above 99%. Moreover, the injection agent was diluted 500 times and used for spraying nearby infected trees, which also achieved good pest control results.

[0036] Table 1 Amounts of raw materials used in Examples 1-4 Example 1 Example 2 Example 3 Example 4 Emamectin benzoate microemulsion (%) 94 90 85 80 Copper sulfate (%) 1 4 3 5 Miscible solvent (%) 5 6 12 15 In order to verify that the pine wood nematode injection agent prepared in the embodiment of the present invention has good efficiency and safety, the low-toxic and long-acting pine wood nematode injection agent provided in the embodiment of the present invention is described through the following test examples.

[0037] Test example The purpose of the test group is to explore the effects of different component ratios on the dry injection agent for pine wood nematode disease, and to detect the pine wood nematode killing rate, safety and stability of the dry injection agent for pine wood nematode disease of the present invention.

[0038] Test objectives: Test groups A, B, C and D respectively use the composition ratios of the pine wood nematode dry injection agent provided in Examples 1-4; the control examples use control group A, control group B, control group C and control group D, wherein: Control group A Use conventional 5% avermectin dry injection agent, and inject 3 ml per centimeter of breast diameter into the stem of a 30-cm-diameter Masson pine tree without adding copper sulfate or miscible solvent.

[0039] Control group B Use 3% emamectin benzoate dry injection agent, 6 ml per cm of breast diameter, without adding copper sulfate and miscible solvent.

[0040] Control group C 95% avermectin benzoate microemulsion (containing 2% avermectin); 0.5% copper sulfate; 4.5% miscible solvent (70% disodium ethylenediaminetetraacetic acid solution) is used: the preparation process adopts the preparation method in Example 1.

[0041] Control group D 75% avermectin benzoate microemulsion (containing 5% avermectin); 6% copper sulfate; 19% miscible solvent (70% disodium ethylenediaminetetraacetic acid solution); the preparation process adopts the preparation method in Example 1.

[0042] Test methods: The specific test methods of test group A, test group B, test group C, test group D, control group A, control group B, control group C and control group D are as follows: Test group A: The stem injection agent was prepared according to the raw material ratio and preparation method described in Example 1. A pine forest was selected, and the diameter of the pine trees in the forest was between 25-35 cm, and there was pine wood nematode infection. In winter, the pine trees were treated with stem injection at a dosage of 1 ml per cm of diameter at breast height; after treatment, the pine trees were sampled and tested regularly (once every 6 months), and the test content included the number of surviving pine wood nematodes, the growth status indicators of the pine trees (such as needle color, branch growth, etc.) and the residue of the stem injection agent in the tree body, and the relevant data were recorded for analyzing the pine wood nematode killing rate, safety and stability indicators.

[0043] Test Group B: The stem injection agent was prepared according to the raw material ratio and preparation method described in Example 2. Another pine forest (pine trees with a breast diameter of about 30-40 cm and early symptoms of pine wilt disease) was selected for stem injection prevention and control. After injection, the pine trees were subjected to detailed inspections once a quarter. The inspection items covered changes in the number of pine nematodes, changes in physiological indicators of pine trees, and whether abnormal phenomena caused by the stem injection agent occurred. Data were collected to evaluate the pine nematode kill rate, safety and stability performance.

[0044] Test group C: The injection agent prepared according to the raw material ratio and preparation method described in Example 3 was injected into a forest moderately infected with pine wood nematode disease (the average breast diameter of pine trees was 35-45 cm). The dosage was also 1 ml per centimeter of breast diameter. After the injection, the pine trees were comprehensively inspected once a month, focusing on the killing effect of pine wood nematodes, the growth health of pine trees, and the stability of the injection agent in the trees.

[0045] Test group D: The injection agent prepared according to the raw material ratio and preparation method described in Example 4 was applied to a forest with certain protection value and potential risk of pine wood nematode disease (the pine tree diameter at breast height was mostly 20-30 cm) for preventive injection. After injection, the pine trees were tested every two months. The test content included signs of pine wood nematode disease, survival of pine wood nematodes, whether the growth of pine trees was affected, and the stability of the injection agent itself. Data were collected to evaluate the pine wood nematode killing rate, safety and stability performance.

[0046] Control group A: conventional 5% avermectin dry injection (common product on the market) was used to select pine trees with similar breast diameter (25-35cm) and the same infection with pine wood nematode disease in the same area as test group A, and the dosage of 3ml per cm of breast diameter was recommended by the manufacturer for dry injection. After injection, the pine trees were sampled and tested at the same time interval as test group A (once every 6 months), and the test content and indicators of concern were also consistent, and the corresponding data were recorded.

[0047] Control group B: Use 3% emamectin benzoate dry injection (a conventional commercial product) to target pine trees with similar environment and breast diameter range (30-40cm) as those in test group B and early symptoms of pine wilt disease, and perform dry injection at a dosage of 6ml per centimeter of breast diameter (the conventional recommended amount of this product); then carry out inspections once a quarter and collect data to evaluate the pine wilt kill rate, safety and stability performance.

[0048] Control group C: A dry injection agent with a different ratio of ingredients from the embodiment of the present invention but related to some raw materials of the present invention was prepared, specifically using 90% avermectin benzoate microemulsion (containing 3% avermectin); 2% copper sulfate; 8% miscible solvent (70% disodium ethylenediaminetetraacetic acid solution). After the dry injection agent was prepared according to the conventional simple preparation process such as stirring and mixing, it was injected into the same moderately infected pine wood nematode forest (average breast diameter of pine trees 35-45cm) as in the test group C, and the injection amount was 1ml per cm of breast diameter. After injection, the pine trees were tested every month, and data were collected to evaluate the pine wood nematode killing rate, safety and stability performance.

[0049] Control group D: A dry injection agent was prepared, the raw material ratio of which was 70% avermectin benzoate microemulsion (containing 4% avermectin); 8% copper sulfate; 22% miscible solvent (70% disodium ethylenediaminetetraacetic acid solution). After being prepared by conventional preparation methods, it was applied to forests with the same conditions as those in test group D (DBH 20-30cm, with hidden dangers of pine wood nematode disease) for dry injection prevention. After injection, relevant indicators of pine trees were tested every two months, and data were collected to evaluate the killing rate, safety and stability of pine wood nematodes.

[0050] Specific detection indicators are shown in Table 2.

[0051] Table 2 Test indicators of each sample Pine wood nematode killing rate (%) Safety (%) stability(%) Experimental Group A 99 100 100 Test Group B 99 100 100 Test Group C 99 100 100 Test Group D 99 100 100 Control group A 60 60 90 Control group B 80 50 90 Control group C 86 90 75 Control group D 90 75 70 As shown in Table 2, by comparing the data of the experimental group and the control group on the key indicators of pine wood nematode killing rate, safety and stability, it can be clearly seen that the differences caused by different dry injection formulations and preparation methods; Pine wood nematode killing rate: Test group: The killing rates of pine wood nematodes in test groups A, B, C, and D can all reach 99%, which indicates that the dry injection agent with different raw material ratios provided by the present invention has excellent killing effects on pine wood nematodes, and can maintain a very high killing rate regardless of how the specific ratios of avermectin benzoate microemulsion, copper sulfate, and miscible solvent are changed within a reasonable range; Control group: The killing rate of control group A (conventional 5% avermectin dry injection) was only 60%, and the killing rate of control group B (3% emamectin benzoate dry injection) was 80%. Even if the proportion of ingredients in control groups C and D was adjusted, the highest killing rate was only 90%, which was much lower than that of the test group. It can be seen that the present invention has a significant improvement in the ability to kill pine wood nematodes through a specific combination of raw materials (synergistic effect of avermectin benzoate microemulsion, copper sulfate, and miscible solvents) compared with conventional single-ingredient or simply-proportioned dry injections, and can more effectively control the damage of pine wood nematode disease.

[0052] Security: Test group: The safety index of each sample in the test group reached 100%, which means that the dry injection agent of the present invention will not produce toxic effects on plants such as pine trees during use according to the established raw material ratio, preparation and use method, and can ensure the healthy growth of plants while ensuring the prevention and control effect; Control group: The safety of control group A was 60%, and that of control group B was 50%. Although the safety of control groups C and D was improved, they only reached 90% and 75% respectively, which were both lower than those of the test group. This indicates that conventional dry injection agents or dry injection agents that are not reasonably formulated according to the present invention may cause risks of harming plants during use.

[0053] Stability: Test group: The stability index of the test group also reached 100%, indicating that the composition, properties and other aspects of the dry injection agent of the present invention can remain stable during storage and use, and will not easily deteriorate, delaminate or reduce the efficacy; Control group: The stability of control groups C and D only reached 75% and 70% respectively. Although the stability of control groups A and B was 90%, it was still lower than the test group. This reflects that the dry injection agent of the present invention has more advantages in stability than other comparative dry injection agents, is more conducive to long-term storage and effective use, and reduces the possibility of fluctuations in the prevention and treatment effect due to product instability.

[0054] In general, the low-toxic and long-acting pine wood nematode injection provided by the present invention is more effective in terms of the performance indicators of pine wood nematode killing rate, safety and stability compared with conventional injection agents or other injection agents with different proportions through the raw material ratio, reasonable preparation method and synergistic effect among the various components. It achieves efficient, long-term, safe and stable effects in preventing and controlling pine wood nematode disease, thereby achieving a good balance between prevention and control effect and safety.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a low-toxic and long-acting dry injection agent for pine wood nematode disease, characterized in that: The following steps are involved: S1. Prepare raw materials: avermectin benzoate microemulsion, copper sulfate and miscible solvent; S2. Mixing copper sulfate and miscible solvent: Pour copper sulfate into the miscible solvent placed in the stirring device, turn on the stirring device to stir, and form a mixed solution; S3. Preparation of dry injection: adding the mixed solution into the stirring container to which the emamectin benzoate microemulsion has been added through a graduated separatory funnel, turning on the stirring function of the stirring container to stir the mixture, so that the three are fully mixed and uniformly obtained to obtain the emamectin benzoate-copper mixture dry injection; S4. Packaging: Pour the prepared dry injection agent into a 50ml long-beak bottle. After filling, seal it with a bottle cap with good sealing performance, label the product information, and place it in a cool, dry, well-ventilated place where children and unauthorized personnel cannot easily reach it for use.

2. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In S1, the avermectin benzoate microemulsion uses a commercial pesticide containing 2%-5% of avermectin.

3. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In the S1, the miscible solvent is a disodium ethylenediaminetetraacetic acid solution with a concentration of 70%.

4. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In S2, the speed of pouring copper sulfate is 0.3s / g-0.8s / g.

5. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In S2, the stirring speed of the stirring device is 300r / min-500r / min.

6. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In S2, the stirring time of the stirring device is 10 min-15 min.

7. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In S3, the speed of adding the mixed solution is 1 mL / min-5 mL / min.

8. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In S3, the stirring speed of the stirring container is 200r / min-400r / min.

9. The method for preparing the low-toxic and long-acting pine wood nematode injection agent according to claim 1, characterized in that: In S3, the stirring time of the stirring container is 20 min-30 min.

10. A low-toxic and long-acting pine wood nematode injection prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The following raw materials are included in weight percentage: Emamectin benzoate microemulsion: 80%-94% of the dry injection weight; Copper sulfate: 1%-5% of the weight of the dry injection agent; Miscible agent: 5%-15% of the dry injection agent by weight.

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