Application of composition for preventing and treating rice-stem borers

Abstract

The invention relates to the technical field of pesticides, and discloses an application of a composition for preventing and treating rice-stem borers, the effective components of the composition are composed of dinotefuran and methoxyfenozide, the weight ratio of dinotefuran to methoxyfenozide is 2: 1-1: 3, and auxiliaries and water are added into the composition to prepare a suspending agent. The composition has an excellent effect on preventing and treating rice-stem borers, the use dosage of active ingredients can be reduced, the preparation process is simple, the cost is low, and the composition can be applied to reduction and synergism of chemical insecticides and green prevention and control of rice-stem borers.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically relating to the use of a composition for controlling rice stem borer. Background Technology

[0002] Methoxyfenozide is a diaromatic hydrazide insect growth regulator and ecdysone insecticide that interferes with the normal growth and development of insects and inhibits feeding. It is mainly used in vegetables and farmland to control lepidopteran pests on vegetables (cucurbits, solanaceous fruits), apples, corn, cotton, grapes, kiwifruit, walnuts, flowers, sugar beets, tea, and field crops (rice, sorghum, soybeans). It is particularly effective against larvae and eggs. It is safe for beneficial insects and mites, exhibiting contact and systemic activity.

[0003] Fipronil is a neonicotinoid insecticide developed by Mitsui Chemicals, Inc. of Japan. Its chemical structure differs significantly from existing neonicotinoid insecticides; its tetrahydrofuran group replaces the previous chloropyridinyl and chlorothiazolyl groups, and it does not contain halogens. This agent exhibits strong contact, stomach poison, and systemic activity, rapid action, long residual effect (3-4 weeks, theoretical residual effect 43 days), and a broad insecticidal spectrum. It is particularly effective against piercing-sucking pests and shows high insecticidal activity even at very low doses. It is mainly used to control aphids, leafhoppers, planthoppers, thrips, whiteflies, and their resistant strains on various crops such as wheat, rice, cotton, vegetables, fruit trees, and tobacco. It is also highly effective against Coleoptera, Diptera, Lepidoptera, Diptera, Beetles, and Somoptera pests, and is highly effective against sanitary pests such as cockroaches, termites, and houseflies.

[0004] The rice stem borer (Chilo suppressalis (Walker)) belongs to the order Lepidoptera and the family Pyralidae. It is one of the most serious and common pests of rice in my country. Damage during the tillering stage causes sheath blight and dead heart, while damage during the heading stage causes damaged plants and whiteheads. Yields are typically reduced by 3% to 5%, but in severe cases, losses can exceed 30%. It is distributed throughout all rice-growing areas in China, with a wider distribution than the rice stem borer and the common rice stem borer, but it is most severe in the Yangtze River basin and areas south of it. In recent years, the number of infestations has shown a significant upward trend. Besides rice, the rice stem borer can also damage water chestnuts, corn, sorghum, sugarcane, rapeseed, broad beans, wheat, as well as weeds such as reeds, barnyard grass, and Leymus chinensis.

[0005] This invention combines fipronil and methoxyfenozide, which have completely different mechanisms of action. The resulting solution has good dispersibility and strong adhesion, which can improve the control effect. It is fast-acting, has a long-lasting effect, can delay the development of pesticide resistance in pests, and is safe for beneficial organisms. Summary of the Invention

[0006] The purpose of this invention is to provide a composition for the control of rice stem borer, aiming to solve the technical problems of severe pest resistance, excessive pesticide application, and high toxicity of commonly used chemical pesticides to fish and aquatic organisms.

[0007] The technical solution of this invention is:

[0008] The use of a composition for controlling rice stem borer is characterized in that: the active ingredients of the composition consist of fipronil and methoxyfenozide, and an adjuvant is added to form a suspension, wherein the weight ratio of fipronil to methoxyfenozide is 2:1 to 1:3, optionally, the weight ratio is 1:1 to 1:3, and optionally the weight ratio is 1:1.

[0009] Furthermore, the total weight of the effective active ingredients of fipronil and methoxyfenozide is 100–500 g / L, with an optional total weight of 200–400 g / L and an optional total weight of 300 g / L.

[0010] Furthermore, the additives are selected from one or more of the following: dispersants, wetting agents, antifreeze agents, preservatives, defoamers, thickeners, pH adjusters, and water.

[0011] Furthermore, the effective ingredient in the composition is used at a rate of 90–150 g / ha, and optionally at a rate of 120–135 g / ha.

[0012] Furthermore, the water consumption for controlling rice stem borer using the composition is 450–750 liters / ha, with a preferred water consumption of 450–600 liters / ha.

[0013] When the composition is prepared as a suspension based on 1000 parts by weight, it includes: 50-300 parts of fipronil, 50-300 parts of methoxyfenozide, 10-100 parts of dispersant, 5-60 parts of wetting agent, 0.1-20 parts of defoamer, 0.5-20 parts of thickener, 10-80 parts of antifreeze, 0.1-30 parts of preservative, 0.1-20 parts of pH adjuster, and water as the balance.

[0014] Compared with the prior art, the composition of the present invention has the following beneficial effects: (1) compared with single agents, the composition has a significant synergistic effect on rice stem borer and significantly improves the control effect; (2) it is low in toxicity and highly effective, and safe for fish and aquatic organisms; (3) it has both rapid and long-lasting effects; (4) it delays the development of pesticide resistance in pests. Detailed Implementation

[0015] The present invention will be further described below with reference to the embodiments. The percentages in the embodiments are all percentage content ratios, but the present invention is not limited thereto.

[0016] First, dispersant, wetting agent, antifreeze, preservative, fipronil, methoxyfenozide, and water are added to a mixing tank and sheared at high speed to fully disperse them, forming a preliminary dispersion. Then, the dispersion is transported to a sand mill by a diaphragm pump for pulverization. The feed speed of the sand mill is adjusted to ensure that the particle size meets the requirements. Finally, the slurry is transported to a mixing tank, where thickener, defoamer, and pH adjuster are added to adjust the viscosity of the material. Samples are taken for quality testing to obtain the finished product.

[0017] Application Example 1 The following examples of suspending agents, based on 1000 parts by weight, contain the following components:

[0018]

[0019]

[0020] Control agent 1: 20% dinotefuran soluble granules, commercially available

[0021] Control agent 2: 240 g / L methoxyfenozide suspension concentrate, commercially available.

[0022] Implementation Example 2:

[0023] Indoor combined toxicity assay of methoxyfenozide, dinotefuran, and mixed formulations against rice stem borer

[0024] The test target was the rice stem borer (Chilo suppressalis). Field larvae were used, and second-instar larvae of uniform size were selected for the experiment after one generation of cultivation.

[0025] 1. Experimental Objective

[0026] By measuring and evaluating the toxicity of fipronil and methoxyfenozide, and their different mixtures, to rice stem borer, the compatibility between the two was clarified, providing a scientific basis for the research and development of fipronil and methoxyfenozide mixtures.

[0027] 2 Experimental Design

[0028] 2.1 Test reagents

[0029] 98% dinotefuran technical grade; 98% methoxyfenozide technical grade.

[0030] 2.2 Reagent Preparation

[0031] Weigh 0.1021g of 98% fipronil technical grade, dissolve it in 5mL LDM, add 0.2mL of Tween 80 emulsifier, stir well, add water to 100mL to prepare a 1000mg / L stock solution. Then take 40mL of the stock solution and add it to 60mL of water containing 0.1% Tween 80 emulsifier to prepare a 400mg / L test solution. Then dilute it with water containing 0.1% Tween 80 emulsifier at a ratio of 2 to prepare 200, 100, 50, 25 and 12.5mg / L, a total of 6 concentrations for testing.

[0032] Weigh 0.1021g of 98% technical grade methoxyfenozide, dissolve it in 5mL of LDM, add 0.2mL of Tween 80 emulsifier, stir well, add water to 100mL to prepare a 1000mg / L stock solution. Take 10mL of the stock solution and add it to 90mL of water containing 0.1% Tween 80 emulsifier to prepare a 100mg / L test solution. Then dilute it with water containing 0.1% Tween 80 emulsifier at a ratio of 2 to prepare 50, 25, 12.5, 6.25 and 3.125mg / L, for a total of 6 concentrations, for testing.

[0033] Based on the ratios of fipronil to methoxyfenozide of 3:1, 2:1, 1:1, 1:2, and 1:3, 15, 13.33, 5, 3.33, and 2.5 mL of fipronil stock solution were measured, and 5, 6.67, 5, 6.67, and 7.5 mL of methoxyfenozide stock solution were measured accordingly. The two solutions were mixed, and any insufficient water volume was supplemented with water containing emulsifier to a final volume of 100 mL. Test solutions of 200, 200, 100, 100, and 100 mg / L were prepared. Each solution was then diluted with water containing 0.1% Tween 80 emulsifier at a 2:1 ratio to obtain six different concentrations for testing.

[0034] Add 95 mL of water containing 0.1% Tween 80 emulsifier to a beaker containing 5 mL of LDM as a blank control.

[0035] 3. Experimental Methods

[0036] Referring to the guidelines for indoor bioassay of pesticides NY / T 1154.14-2008, the method of soaking rice stems for insect inoculation was adopted.

[0037] 4. Data Survey and Statistical Analysis

[0038] 4.1 Survey Time and Methods

[0039] After 96 hours of treatment, check the number of dead and live larvae in each treatment. The criterion for larval mortality is: the larvae are considered dead if they do not react when gently touched with the tip of pointed tweezers.

[0040] 4.2 Data Statistical Analysis

[0041] Calculate the co-toxicity coefficient (CTC) according to Sun Yunpei's method, and evaluate the synergistic effect of the mixed agents based on the co-toxicity coefficient (CTC). That is, CTC ≤ 80 indicates antagonistic effect, 80 < CTC < 120 indicates additive effect, and CTC ≥ 120 indicates synergistic effect. The formula for calculating the co-toxicity coefficient is as follows:

[0042]

[0043] The theoretical toxicity index (TTI) of the mixture = the toxicity index of agent A × the percentage of agent A in the mixture (%) + the toxicity index of agent B × the percentage of agent B in the mixture (%)

[0044]

[0045] 5 Experimental results

[0046] Table 1 Toxicity determination results of different ratios of dinotefuran and methoxyfenozide against Chilo suppressalis in rice

[0047]

[0048] It can be seen from Table 1 of the test results that the test agent methoxyfenozide has relatively high toxicity to Chilo suppressalis in rice, with LC

[0052] ,

[0051] ,

[0050] ,

[0049] , , , , value of 18.43 mg / L and LC 90 value of 88.29 mg / L; dinotefuran also has good toxicity, with LC 50 value of 73.46 mg / L and LC 90 value of 378.34 mg / L; the toxicities (LC 50 ) of different ratios of the two agents mixed against Chilo suppressalis in rice are 35.98, 28.23, 19.28, 18.11, and 17.19 mg / L respectively, and the co-toxicity coefficients CTC reach 116.90, 130.42, 152.84, 135.64, and 131.92 respectively. It shows that within the range of the test design ratios of 2:1 to 1:3 for dinotefuran and methoxyfenozide, CTC is greater than 120, indicating a synergistic effect. Among them, the co-toxicity coefficient (CTC) of the 1:1 ratio is the largest and the synergistic effect is the most significant.

[0049] Application Example 3: Field efficacy test of Examples 1 - 6 for controlling Chilo suppressalis in rice 1 Test purpose

[0050] Verify the control effect of the dinotefuran·methoxyfenozide suspension concentrate developed by the applicant against Chilo suppressalis in rice and its safety, clarify the field application dosage and application technology, and provide a scientific basis for pesticide registration.

[0051] 2 Test basis

[0052] This experiment complies with the "Good Manufacturing Practice for Pesticide Registration Trials", the agricultural industry standard "Good Manufacturing Practice for Pesticide Registration Field Efficacy Trials" (NY / T2885-2016), and the guidelines for pesticide field efficacy trials (I).

[0053] 3 Experimental Locations

[0054] This experiment was conducted in Hubei, Anhui, Shaanxi, and Shandong provinces. 4. Selection of experimental subjects, crops, and varieties.

[0055] Experimental subject: Rice stem borer.

[0056] 5. Experimental Design and Arrangement

[0057] 5.1 Dosage and Numbering of Pharmaceuticals

[0058] Table 2 Experimental Design of Test Reagents

[0059]

[0060]

[0061] 5.2 Application time and frequency

[0062] Apply pesticide once during the rice tillering stage, from the peak egg hatching period to the peak occurrence of young larvae of the rice stem borer.

[0063] 5.3 Usage Capacity

[0064] Water consumption is 450–600 liters per hectare.

[0065] 5.4 Survey Time and Frequency

[0066] One survey was conducted before the pesticide was applied, and another survey was conducted after the rice had dried heart and reached maturity.

[0067] 5.5 Method for Calculating Drug Efficacy

[0068]

[0069] 6 Experimental Results

[0070] Table 3. Field efficacy test results of fipronil·methoxyfenozide suspension for controlling rice stem borer.

[0071]

[0072]

[0073] The experimental results are shown in Table 3. Table 3 shows that 3 days after application, the control efficacy of the tested pesticides, fipronil·methoxyfenozide suspension at dosages of 25 ml / mu and 30 ml / mu, against rice stem borers ranged from 82.2% to 93.07%. The control pesticides, 20% fipronil soluble granules and 240 g / L methoxyfenozide suspension at dosages of 50 g / mu and 28 ml / mu, respectively, against rice stem borers ranged from 71.0% to 85.15%. It can be seen that the control efficacy of the tested pesticides was significantly better than that of the control pesticides alone. Analysis of variance shows a highly significant difference compared to the control pesticides alone.

[0074] In summary, the tested pesticide, fipronil·methoxyfenozide suspension, showed good control efficacy against rice stem borer and was safe for rice within the tested dosage range.

Claims

1. The use of a composition for controlling rice stem borer, characterized in that: The active ingredients of the composition consist of fipronil and methoxyfenozide, and an adjuvant is added to form a suspension, wherein the weight ratio of fipronil to methoxyfenozide is 2:1 to 1:

3.

2. The use according to claim 1, characterized in that: The weight ratio of fipronil to methoxyfenozide in the composition is 1:1 to 1:3, and optionally 1:

1.

3. The use according to claim 1 or 2, characterized in that: The total effective active ingredients of fipronil and methoxyfenozide have a total weight of 100-500 g / L, with an optional total weight of 200-400 g / L and an optional total weight of 300 g / L.

4. The use according to claim 1, characterized in that: The additives are selected from one or more of the following: dispersants, wetting agents, antifreeze agents, preservatives, defoamers, thickeners, pH adjusters, and water.

5. The use according to any one of claims 1 to 4, characterized in that: The effective ingredient dosage of the composition is 90-150 g / ha, and optionally 120-135 g / ha.

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