Rational use of two pesticides

Abstract

This invention provides a rational application technique for two pesticides, evaluates the toxicity of combined exposure to abamectin and cyazofamid on bee mortality, and proposes an application interval for these two pesticides through a study on the application isolation period. The application dosage of abamectin is 0.75-4.5 g (active ingredient) / acre, and the application dosage of cyazofamid is 5.5-6.5 g (active ingredient) / acre, with an application interval of more than 1 day. Preferably, when abamectin is applied first and then cyazofamid, the application interval is 3 days; when cyazofamid is applied first and then abamectin, the application interval is 5 days. This invention suggests that the mixture of abamectin and cyazofamid should be used cautiously in agricultural production, and the application interval must be strictly observed to reduce adverse impacts on the ecological environment. It also provides a reference for the study of the toxicity testing and application interval of combined exposure to other types of pesticides on bee mortality and provides important scientific basis for the monitoring and early warning of farmland environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of toxic pollution control, and more specifically, to the rational use techniques of two pesticides, particularly to the application methods of azoxystrobin and cyazofamid. Background Technology

[0002] In agricultural production, to broaden the target pests, improve the control effect on single pests, and delay the development of pesticide resistance, it is often necessary to use multiple pesticides simultaneously or sequentially. Different pesticides often exhibit complex interactions, affecting each other's absorption, distribution, and metabolic transformation, resulting in synergistic toxicity effects, such as synergistic, additive, and antagonistic effects. Currently, many ecotoxicological effects cannot be explained by the mechanisms of action of a single pesticide, and past evaluation standards based on single effects cannot accurately reflect the objective requirements of environmental quality. Therefore, conducting research on the synergistic toxicity of pesticides is of great guiding significance for establishing a technical system of ecological diagnostic indicators for mixed pollution, correctly evaluating the migration and transformation behavior of pollutants under mixed pollution conditions, and helping people to take effective control measures. It also provides a reference for the rational use of multiple pesticides.

[0003] Fenpyroximate is a novel insecticide and acaricide primarily used to control mites on various crops, such as the two-spotted spider mite, the Shennong spider mite, and leafhoppers. It possesses excellent protective activity and some systemic therapeutic activity, a long-lasting effect, resistance to rain washout, and is safe and convenient to use. Cyazofamid is a foliar contact protective fungicide mainly used on crops such as cucumbers, potatoes, grapes, and tomatoes, with particularly significant effects against potato late blight (Phytophthora festans). It can also control downy mildew (Pseudoperonospora humuli) in cucumbers and melons. This agent is a low-toxicity fungicide with strong systemic protective properties. After application, it is rapidly absorbed by crops, has a long-lasting effect, stable efficacy, low dosage, resistance to rain washout, and can be mixed with various pesticides. Because the mixture of azoxystrobin and cyazofamid has good control efficacy against harmful target organisms, it is widely used in agricultural production, thus constituting mixed pollution.

[0004] Honeybees are important pollinating insects, pollinating tens of thousands of plant species worldwide and playing a vital role in increasing agricultural production and income. They also provide humans with abundant products such as honey, propolis, and beeswax. However, the widespread distribution, hairy bodies, high mobility, and singular foraging characteristics of honeybees make them highly sensitive to the environment, often referred to as environmental pollutants. In recent years, honeybees worldwide have experienced severe population decline, a condition scientists call colony collapse disorder (CCD). Many factors contribute to this decline, with the extensive use of pesticides in agricultural production being a significant contributing factor. Given the widespread practice of pesticide contamination in agriculture, studying its impact on honeybee mortality toxicity is crucial for assessing farmland environmental pollution.

[0005] Currently, both azoxystrobin and cyazofamid are still widely used as pesticides. In certain scenarios, azoxystrobin and cyazofamid are used in combination as a pesticide. Although there have been studies on the toxic effects of azoxystrobin and cyazofamid as single contaminants, there are still no reports on the combined mortality toxicity of bees caused by the combined contamination of azoxystrobin and cyazofamid. Furthermore, there has been no in-depth research on how to properly apply these two pesticides in the same location from the perspective of protecting the ecosystem and reducing pollution, nor has any corresponding guidance been provided on such application methods. Summary of the Invention

[0006] To address the aforementioned issues, this invention conducts research on the toxicity of azoxystrobin and cyazofamid to bees, laying a theoretical foundation for the scientific and rational use of pesticides and evaluating the ecological risks of pesticide mixing pollution, and providing guidance on application methods when azoxystrobin and cyazofamid are applied in the same location.

[0007] This invention provides two methods for applying pesticides, wherein the two pesticides are abamectin and cyazofamid, and abamectin and cyazofamid are applied according to the industry-recommended dosage. When abamectin and cyazofamid are applied at the same location, there must be an application interval.

[0008] The industry-recommended dosages here refer to the dosages recorded in the pesticide registration certificates for abamectin and cyazofamid. The application dosage for abamectin is 0.75-4.5 g (active ingredient) / acre, and for cyazofamid, it is 5.5-6.5 g (active ingredient) / acre. Based on the application characteristics of abamectin and cyazofamid, approximately 30-90 L of water is needed per acre for spraying. Therefore, it can be deduced that when applying according to the industry-recommended dosages, the application dosage for abamectin is 25-50 mg / L, and for cyazofamid, it is 61.1-216.7 mg / L.

[0009] The application interval here refers to the time interval that must exist between applying abamectin and cyazofamid separately at the same location.

[0010] Furthermore, the application interval between azoxystrobin and cyazofamid when applied at the same location should be more than 1 day.

[0011] Preferably, when abamectin is applied first and then cyazofamid is applied at the same location, the application interval is 3 days; when cyazofamid is applied first and then abamectin is applied, the application interval is 5 days.

[0012] On the other hand, the present invention also provides a method for determining how to obtain the application methods of the two pesticides, mainly for determining the toxicity of the two pesticides to bees.

[0013] Furthermore, the determination of the toxicity of the two pesticides to bees mainly includes: toxicity testing of a single pesticide on bees; toxicity testing of combined exposure to the two pesticides on bees; and toxicity testing of the two pesticides after an application interval. The toxicity testing of a single pesticide on bees refers to testing the toxicity of either abamectin or cyazofamid to bees when applied alone. The toxicity testing of combined exposure to the two pesticides refers to testing the toxicity of abamectin and cyazofamid to bees when both are exposed together, testing whether there is a synergistic effect in their toxicity to bees. The toxicity testing of the two pesticides after an application interval means that there must be a certain application interval between the application of abamectin and cyazofamid alone, and testing whether there is still a synergistic effect in their toxicity to bees if the application interval is short, thereby selecting the most suitable application interval.

[0014] Furthermore, the toxicity test on bees after the application interval of the two pesticides refers to first applying abamectin alone, and after the application interval, then applying cyazofamid alone and conducting a toxicity test on bees, or first applying cyazofamid alone, and after the application interval, then applying abamectin alone and conducting a toxicity test on bees.

[0015] Furthermore, the toxicity test on bees during the application interval of the two pesticides refers to testing the combined toxicity of the two pesticides on bees within an application interval ranging from 1 day to 8 days or more, and analyzing and judging based on the test results to select the appropriate application interval for azoxystrobin and cyazofamid.

[0016] Furthermore, the basis for analyzing and judging the test results is the synergistic effect of azoxystrobin and cyazofamid on bee toxicity.

[0017] Furthermore, the toxicity test on bees refers to the evaluation of mortality toxicity in bees.

[0018] This invention processes bee mortality toxicity test data using DPS statistical analysis software (version: V14.10), and uses probability value analysis to statistically analyze the bee mortality toxicity data to determine the LC. 50 The 95% confidence limit was determined. This invention uses the Marking additive index method to evaluate the combined toxicity of azoxystrobin and cyazofamid.

[0019] This invention conducts a study on the toxicity of combined exposure to azoxystrobin and cyazofamid on bees, obtaining basic data on the combined toxicity of mixed pollution by azoxystrobin and cyazofamid. This provides basic data for correctly evaluating the biological effects of the two pesticides as pollutants on bees, and provides a scientific basis for resource protection and environmental risk assessment in farmland environments.

[0020] This invention reveals a significant synergistic effect between combined exposure to azoxystrobin and cyazofamid on bee mortality toxicity, indicating that their coexistence can have serious adverse effects on the ecological environment. Although mixtures of azoxystrobin and cyazofamid are widely used in agricultural production to improve pest control, their coexistence can also produce toxic side effects on the ecological environment. Therefore, mixtures of azoxystrobin and cyazofamid should be used cautiously in agricultural production to minimize adverse impacts on the ecological environment.

[0021] Meanwhile, through research on the application isolation period, this invention has determined that when abamectin or cyazofamid is applied alone, and the application interval is less than 3 days, there is still a synergistic effect on bee toxicity. Therefore, it is recommended that when abamectin and cyazofamid are applied at the same location, the application interval should not be less than 1 day. Preferably, when abamectin is applied first and then cyazofamid is used, the application interval is 3 days; when cyazofamid is applied first and then abamectin is used, the application interval is 5 days.

[0022] This study evaluated the toxicity of combined exposure to abamectin and cyazofamid on bee mortality and proposed the concept of an application interval for these two pesticides. This provides a reference for the study of toxicity testing and application intervals of combined exposure to other types of pollutants on bee mortality, and will also provide important scientific basis for the monitoring and early warning of farmland environmental pollution. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the embodiments. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention and do not limit it in any way.

[0024] 1. Test materials

[0025] (1) Test organisms

[0026] The honeybee species used in the test is adult worker honeybees of *Apis mellifera* L. (Italian honeybee) recommended by OECD 213. During the test, healthy adult worker honeybees of consistent size from the same colony are selected for the test. For the acute oral toxicity test, the honeybees are starved for 2 hours under indoor dark conditions to ensure that the honeybees are in a starved state at the start of the test.

[0027] (2) Test agents

[0028] The tested pesticides are fenpyroximate and cyazofamid technical materials, both with a purity of >95%.

[0029] (3) Test containers

[0030] The test bee cage is a 400mL round wide-mouth polypropylene jar (diameter × height: 8×10 cm), with a 7.5 cm diameter hole on the top of the cage, covered with a 3×3 mm wire mesh to prevent honeybees from escaping.

[0031] 2. Test quality control

[0032] A test is valid if the mortality rate of honeybees in the control group is <10%.

[0033] 3. Method for evaluating combined toxicity of pesticides

[0034] According to the Marking additive index method, the combined toxicity of insecticides and fungicides is evaluated. The following formula is used to calculate the sum of biological toxic effects S: S = Am / Ai + Bm / Bi, where Am and Bm are respectively the toxicities (LC 50 ) of each toxicant in the mixture, and Ai and Bi are respectively the toxicities (LC 50 ) when toxicants A and B act alone; convert S into the additive index AI (Additive Index). When S ≤ 1, AI = (1 / S) - 1.0; when S > 1, AI = 1.0 - S. Finally, AI is used to evaluate the mixing effect of pesticides: when -0.2 < AI < 0.25, it is additive effect (Addition); when AI ≥ 0.25, it is synergism (Synergism); when AI ≤ -0.2, it is antagonism (Antagonism). Fold increase in toxicity = AI + 1.

[0035] Example 1 Toxicity test of insecticide to honeybees

[0036] This embodiment selected 10 commonly used insecticides, and weighed a certain amount of each insecticide technical grade, dissolved completely in acetone, then added 10% Tween 80 (w / v), shook well, and finally diluted to volume with acetone to prepare a high-concentration stock solution. The concentration range set completely covered the industry-recommended dosage of the corresponding insecticides. A 50% sucrose aqueous solution was set as a blank control group. The diluted solutions were poured into 20 mL glass scintillation bottles, and two small holes (1.6 mm in diameter) were drilled in the plastic caps of the scintillation bottles. Then, the scintillation bottles containing 20 mL of insecticide solution and distilled water were placed upside down on top of each test cage. Each test cage contained 20 bees as a replicate, and there were 4 replicates for both the experimental and control groups. The bee cages were placed under low-light conditions of 25±1℃ and 60–70% relative humidity, and the mortality rate was checked 2 days after exposure. The DPS statistical analysis software (version V14.10) was used to statistically analyze the bee mortality toxicity data using probability value analysis to determine the LC. 50 And its 95% confidence limit, LC50 of 10 pesticides and insecticides on bees 50 The values ​​are shown in Table 1.

[0037] Table 1: Toxicity of Insecticides to Bees

[0038] Imidacloprid 0.24 bromocyanamide 308 acetonitrile 0.68 Fipronil 0.27 Thiamethoxam 0.15 Thiamethoxam 0.13 Emamectin benzoate 0.11 Azoxystrobin 110 Lufenuron 249 Cypermethrin 7.56

[0039] The results showed that, based on the industry-recommended dosage and median lethal concentration (LD50) of insecticides for oral toxicity to bees, only bromocyanamide, azoxystrobin, and lufenuron showed low oral toxicity to bees among the 10 insecticides mentioned above.

[0040] Example 2: Toxicity test of the bactericide on bees

[0041] This embodiment selected 10 commonly used fungicides for toxicity testing. The testing method for fungicide-induced bee mortality was the same as in Example 1. Eleven concentrations of the 10 fungicides were set at certain intervals, completely covering the industry-recommended dosage for each fungicide. Four replicates were set for each concentration (one replicate per test cage), and four blank control groups without any fungicide were also included. DPS statistical analysis software (version V14.10) was used to statistically analyze the bee mortality toxicity data using probability value analysis to determine the LC. 50 and its 95% confidence limit, LC50 of 10 fungicides against bees 50 The values ​​are shown in Table 2.

[0042] Table 2: Toxicity of fungicides to bees

[0043]

[0044] The results showed that, based on the industry-recommended dosage and median lethal concentration (LD50) for oral toxicity to bees, among the 10 fungicides mentioned above, only boscalid, pyraclostrobin, and cyazofamid had extremely low toxicity to bees.

[0045] Example 3: Toxicity test of combined exposure to insecticides and fungicides to bees

[0046] This embodiment involves testing the toxicity of a mixture of insecticides and fungicides to bees using an isotoxicity design. The insecticides are the low-toxicity bee-causing agents obtained in Example 1: bromocyanamide, azoxystrobin, and lufenuron. The fungicides are the extremely low-toxicity bee-causing agents obtained in Example 2: cymoxanil, pyraclostrobin, and cyazofamid. The insecticides and fungicides are combined in pairs for combined exposure toxicity testing on bees. The isotoxicity design uses the LC50 of the number of bee deaths caused by a single pesticide. 50 The value is one toxicity unit. Six different concentrations of the mixed pesticide were set at equal logarithmic intervals based on a 1:1 mixing ratio of the two individual pesticides' toxicity units. The toxicity test method was the same as in Example 1. The concentration range for the isotoxicity setting completely covered the industry-recommended dosages of the insecticide and fungicide. Two days after exposure, the number of deaths was counted, and the LC50 of the mixed pesticide and fungicide in the mixed system was calculated. 50 The AI ​​value was calculated based on the data obtained in Examples 1 and 2, and the results are shown in Table 3.

[0047] Table 3: Toxicity of Mixed Pesticides to Bees

[0048]

[0049]

[0050] The results showed that the combination of abamectin and cyazofamid had a significant synergistic effect on bee toxicity, meaning that the toxicity of the two combined to bees was multiples of the sum of the toxicity of the two alone, while the toxicity of other combinations to bees was only additive.

[0051] Let's further examine the mechanism of action of pesticides: Azoxystrobin is a fungicide that inhibits the mitochondrial electron transport chain, interfering with the energy metabolism of pathogens and leading to their death. Cyazofamid is also a fungicide that inhibits the mitochondrial electron transport chain, but its site of action differs from that of azoxystrobin. Azoxystrobin acts on the Q center of the inner mitochondrial membrane (the Q center is a complex in the mitochondrial respiratory chain, composed of multiple proteins and cofactors. The Q center is the third complex in the respiratory chain, connecting cytochrome c oxidoreductase and cytochrome c reductase, thereby transferring electrons from NADH and FADH2 to oxygen), while azoxystrobin acts on the outer Q center (the outer mitochondrial membrane, the outermost completely enclosed unit membrane of the mitochondria, serving as the boundary membrane of this organelle. The outer mitochondrial membrane is approximately 6-7 nm thick and smoother than the inner mitochondrial membrane). When these two pesticides are applied simultaneously, a double blockade is formed, completely disabling the mitochondrial electron transport chain of the pathogen, thus accelerating its death. This is the principle behind the synergistic toxicity-enhancing effect of azoxystrobin and cyazofamid.

[0052] Example 4: Toxicity test on bees after exposure to azoxystrobin and cyazofamid with a 1-day interval.

[0053] This embodiment involves a toxicity test on bee mortality caused by exposure to abamectin and cyazofamid at a 1-day interval, using an isotoxicity design. The isotoxicity design uses the LC-weighted average (LC-weighted average) of a single pesticide on the number of bee deaths. 50 A toxicity unit was used as the basis for determining the concentration of each pesticide. Six different concentrations were set at logarithmic intervals using two single pesticides at a 1:1 toxicity unit ratio (0.50 mg / L + 31.5 mg / L, 1.5 mg / L + 94.5 mg / L, 4.5 mg / L + 284 mg / L, 13.5 mg / L + 851 mg / L, 40.5 mg / L + 2552 mg / L, and 122 mg / L + 7655 mg / L, respectively). The test was conducted in two batches: one batch was treated with abamectin first, left at room temperature for 1 day, and then treated with cyazofamid; the other batch was treated with cyazofamid first, left at room temperature for 1 day, and then treated with abamectin. After both pesticides were added, bee toxicity testing was conducted using the same method as in Example 1. The concentration ranges set for equivalent toxicity completely covered the industry-recommended dosages of abamectin and cyazofamid (25-50 mg / L and 61.1-216.7 mg / L, respectively). Two days after exposure, the number of deaths was counted, and the LC50 of each pesticide was calculated. 50 value.

[0054] Example 5: Toxicity test on bees after exposure to abamectin and cyazofamid at 3-day intervals.

[0055] This embodiment involves a toxicity test on bee mortality caused by exposure to abamectin and cyazofamid at a 3-day interval, using an isotoxicity design. The isotoxicity design uses the LC-weighted average (LC-weighted average) of a single pesticide on the number of bee deaths.50 A toxicity unit was used as the basis for determining the concentration of each pesticide. Six different concentrations were set at logarithmic intervals using two single pesticides in a 1:1 toxicity unit ratio (a mixture of 0.50 mg / L + 31.5 mg / L, 1.5 mg / L + 94.5 mg / L, 4.5 mg / L + 284 mg / L, 13.5 mg / L + 851 mg / L, 40.5 mg / L + 2552 mg / L, and 122 mg / L + 7655 mg / L, respectively). The test was conducted in two batches: one batch was treated with 0.50 mg / L first, left at room temperature for 3 days, and then treated with cypermethrin; the other batch was treated with cypermethrin first, left at room temperature for 3 days, and then treated with 0.50 mg / L first. After both pesticides were added, bee toxicity testing was conducted using the same method as in Example 1. The concentration ranges set for equivalent toxicity completely covered the industry-recommended dosages of 0.50 mg / L and 61.1-216.7 mg / L for 0.50 mg / L and cypermethrin, respectively. Two days after exposure, the number of deaths was counted, and the LC50 of each pesticide was calculated. 50 value.

[0056] Example 6: Toxicity test on bees after exposure to abamectin and cyazofamid at 5-day intervals.

[0057] This embodiment involves a toxicity test on bee mortality caused by exposure to abamectin and cyazofamid at a 5-day interval, using an isotoxicity design. The isotoxicity design uses the LC-weighted average (LC-weighted average) of a single pesticide on the number of bee deaths. 50 A toxicity unit was used as the basis for determining the concentration of each pesticide. Six different concentrations were set at logarithmic intervals using two single pesticides in a 1:1 toxicity unit ratio (a mixture of 0.50 mg / L + 31.5 mg / L, 1.5 mg / L + 94.5 mg / L, 4.5 mg / L + 284 mg / L, 13.5 mg / L + 851 mg / L, 40.5 mg / L + 2552 mg / L, and 122 mg / L + 7655 mg / L, respectively). The test was conducted in two batches: one batch was treated with 0.50 mg / L first, left at room temperature for 3 days, and then treated with cypermethrin; the other batch was treated with cypermethrin first, left at room temperature for 3 days, and then treated with 0.50 mg / L first. After both pesticides were added, bee toxicity testing was conducted using the same method as in Example 1. The concentration ranges set for equivalent toxicity completely covered the industry-recommended dosages of 0.50 mg / L and 61.1-216.7 mg / L for 0.50 mg / L and cypermethrin, respectively. Two days after exposure, the number of deaths was counted, and the LC50 of each pesticide was calculated. 50 value.

[0058] Example 7: Toxicity test on bees after exposure to azoxystrobin and cyazofamid at an 8-day interval.

[0059] This embodiment involves a toxicity test on bee mortality caused by exposure to abamectin and cyazofamid at an 8-day interval, using an isotoxicity design. The isotoxicity design uses the LC-weighted average (LC-weighted average) of a single pesticide on the number of bee deaths. 50A toxicity unit was used as the basis for determining the concentration of each pesticide. Six different concentrations were set at logarithmic intervals using two single pesticides in a 1:1 toxicity unit ratio (a mixture of 0.50 mg / L + 31.5 mg / L, 1.5 mg / L + 94.5 mg / L, 4.5 mg / L + 284 mg / L, 13.5 mg / L + 851 mg / L, 40.5 mg / L + 2552 mg / L, and 122 mg / L + 7655 mg / L, respectively). The test was conducted in two batches: one batch was treated with 0.50 mg / L first, left at room temperature for 3 days, and then treated with cypermethrin; the other batch was treated with cypermethrin first, left at room temperature for 3 days, and then treated with 0.50 mg / L first. After both pesticides were added, bee toxicity testing was conducted using the same method as in Example 1. The concentration ranges set for equivalent toxicity completely covered the industry-recommended dosages of 0.50 mg / L and 61.1-216.7 mg / L for 0.50 mg / L and cypermethrin, respectively. Two days after exposure, the number of deaths was counted, and the LC50 of each pesticide was calculated. 50 value.

[0060] Example 8: Analysis of Bee Toxicity Test Results

[0061] After the experiment, the mortality rate of bees in the blank control group was less than 10% for 8 days. Therefore, this experiment met the quality control requirements and was valid.

[0062] The experimental results of Examples 1, 2, and 3 were analyzed, and the results are shown in Table 4. The results show that at the tested concentrations, both azoxystrobin and cyazofamid had significant effects on bee mortality, and for the same pesticide, the mortality rate increased with increasing exposure concentration. The LC50 of cyazofamid on bee mortality is also shown. 50 The value was 6932 (5429–8851) mg / L, which was significantly higher than the LC50 of pyridaben for bee mortality. 50 The concentration of 110 (86.1–130) mg / L indicates that cyazofamid has a significantly lower toxicity to bees than azoxystrobin. When azoxystrobin and cyazofamid are combined in an equitoxic ratio, they exhibit a clear synergistic effect on bee mortality, with an AI value of 2.24, meaning a toxicity increase factor of 3.24. This indicates that the coexistence of these two pesticides can have a significant adverse impact on bee populations.

[0063] Table 4. Mortality toxicity effects of combined exposure to azoxystrobin and cyazofamid on bees.

[0064]

[0065] a LC50 of bee mortality when exposed to abamectin and cyazofamid alone 50 (95% confidence limit).

[0066] bLC50 of bee mortality from combined exposure to abamectin and cyazofamid 50 (95% confidence limit).

[0067] c Additive exponent value

[0068] The experimental results of Examples 4, 5, 6, and 7 are analyzed below, and the results are shown in Table 5:

[0069] Table 5. Mortality toxicity effects of alternating treatments with abamectin and cyazofamid on bees.

[0070]

[0071] Note: Order of application: A means add abamectin first, and then add cyazofamid after the interval period; B means add cyazofamid first, and then add abamectin after the interval period.

[0072] The test results show that:

[0073] In Example 4, when the interval between the treatments with azoxystrobin and cyazofamid was 1 day, a significant synergistic effect was observed on the number of bee deaths. When azoxystrobin was added first, followed by cyazofamid 1 day later, the AI ​​value was 1.2, meaning the toxicity increased by a factor of 2.2, indicating a significant adverse effect on the bee population. When cyazofamid was added first, followed by azoxystrobin 1 day later, the AI ​​value was 1.75, slightly higher than the former, but still had a significant adverse effect on bee deaths, with a toxicity increase factor of 2.75.

[0074] In Example 5, when the interval between treatment with azoxystrobin and cyazofamid was 3 days, two scenarios emerged regarding bee mortality. When azoxystrobin was added first, followed by cyazofamid 3 days later, the AI ​​value was 0.17, indicating an additive effect rather than a synergistic one on bee mortality. When cyazofamid was added first, followed by azoxystrobin 3 days later, the AI ​​value was 0.28, meaning the toxicity increased by a factor of 1.28, indicating a significant adverse impact on the bee population. Therefore, a 3-day isolation period is appropriate when azoxystrobin is added first, followed by cyazofamid.

[0075] In Example 6, when the interval between treatments with abamectin and cyazofamid was 5 days, the effects on bee mortality were additive. When abamectin was applied first, followed by cyazofamid 5 days later, the AI ​​value was 0.078, indicating an additive effect rather than a synergistic one on bee mortality. When cyazofamid was applied first, followed by abamectin 5 days later, the AI ​​value was 0.12, slightly higher than the former, also indicating an additive effect rather than a synergistic one on bee mortality. Therefore, a 5-day isolation period is appropriate when cyazofamid is applied first, followed by abamectin.

[0076] In Example 7, when the interval between treatments with azoxystrobin and cyazofamid was 8 days, the effects on bee mortality were additive. When azoxystrobin was added first, followed by cyazofamid 8 days later, the AI ​​value was -0.16, indicating no synergistic effect on bee mortality, but rather an additive effect. Therefore, when azoxystrobin was added first and then cyazofamid, the synergistic effect on bee toxicity disappeared after the 8-day isolation period. When cyazofamid was added first, followed by azoxystrobin 8 days later, the AI ​​value was -0.044, slightly higher than the former, indicating no synergistic effect on bee mortality, but rather an additive effect. Therefore, when cyazofamid was added first and then azoxystrobin, the synergistic effect on bee toxicity disappeared after the 8-day isolation period. This demonstrates that after the 8-day interval, the synergistic effect of alternating treatments with azoxystrobin and cyazofamid on bee toxicity completely disappeared.

[0077] Therefore, when applying abamectin and cyazofamid at the same location, both abamectin and cyazofamid are applied according to industry-recommended dosages. The dosage of abamectin is 0.75-4.5 g (active ingredient) / acre, and the dosage of cyazofamid is 5.5-6.5 g (active ingredient) / acre. That is, when the dosage of abamectin is 25-50 mg / L and the dosage of cyazofamid is 61.1-216.7 mg / L, the application interval shall not be less than 1 day. Preferably, when abamectin is applied first and then cyazofamid, a 3-day application interval must be implemented; when cyazofamid is applied first and then abamectin, a 5-day application interval must be implemented.

[0078] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for reducing the toxicity of two pesticides to bees, characterized in that, The two pesticides are an insecticide and a fungicide, respectively. The insecticide is abamectin, and the fungicide is cyazofamid. The combined exposure of abamectin and cyazofamid has a synergistic effect on bee mortality toxicity. When abamectin and cyazofamid are applied at the same location, there must be an application interval. The application dosage of abamectin is 0.75-4.5 g / mu, and the application dosage of cyazofamid is 5.5-6.5 g / mu. When abamectin is applied first and then cyazofamid, the application interval is 3 days. When cyazofamid is applied first and then abamectin, the application interval is 5 days.

2. The method for determining the application method as described in claim 1, characterized in that, The toxicity of two pesticides to bees was determined.

3. The determination method as described in claim 2, characterized in that, The determination of the toxicity of the two pesticides to bees mainly includes: toxicity test of a single pesticide to bees; toxicity test of bees after combined exposure to the two pesticides; and toxicity test of bees after the application interval of the two pesticides.

4. The determination method as described in claim 3, characterized in that, The toxicity test on bees after the application interval for the two pesticides refers to applying abamectin alone first, then applying cyazofamid alone after the application interval, and conducting a toxicity test on bees; or applying cyazofamid alone first, then applying abamectin alone after the application interval, and conducting a toxicity test on bees.

5. The determination method as described in claim 4, characterized in that, The toxicity test on bees when implementing the application interval of the two pesticides refers to testing the combined toxicity of the two pesticides on bees by applying them at intervals ranging from 1 day to 8 days, analyzing the test results, and selecting the appropriate application interval for the two pesticides.

6. The determination method as described in claim 5, characterized in that, The toxicity test on bees refers to the evaluation of mortality toxicity in bees.

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