An active insecticide for preventing and treating citrus fruit flies

Abstract

The present application belongs to the technical field of insecticides, and particularly relates to an active insecticide for preventing and treating Bactrocera minax. The active insecticide comprises an effective component and an auxiliary component, wherein the effective component is compounded by ozanimod with tetrahydro-1, 1-dimethyl-3-(2-propynyl)-1H-1, 2, 4-triazol-5-amine or butenflucytyl. The mass ratio of ozanimod to tetrahydro-1, 1-dimethyl-3-(2-propynyl)-1H-1, 2, 4-triazol-5-amine is 1-30:20-1. The mass ratio of ozanimod to butenflucytyl is 1-10:10-1. The present application determines the joint action type of ozanimod compounded with tetrahydro-1, 1-dimethyl-3-(2-propynyl)-1H-1, 2, 4-triazol-5-amine or butenflucytyl on Bactrocera minax by using the method of feeding with cotton balls. It is found that ozanimod compounded with tetrahydro-1, 1-dimethyl-3-(2-propynyl)-1H-1, 2, 4-triazol-5-amine or butenflucytyl has a synergistic effect on killing Bactrocera minax at different mass ratios. Compared with single component, the present application can improve the prevention and treatment effect on Bactrocera minax, reduce the pesticide dosage, decrease pesticide residues, reduce environmental pollution, and help the green, healthy and sustainable development of the pomelo industry.

Description

Technical Field

[0001] This invention belongs to the field of insecticide technology, specifically relating to an active insecticide for controlling the fruit fly in starfruit and citrus fruit. Background Technology

[0002] Star fruit belongs to the genus *Amanita* in the family Oxalidaceae. It can flower and bear fruit multiple times a year and has high economic value. During its growth and development, star fruit is susceptible to damage from various pests, including the oriental fruit fly, the bird tufted moth, aphids, and spider mites. Among these, the oriental fruit fly has a high reproductive capacity, with 8-9 generations per year. It is a year-round pest with strong adaptability, no obvious overwintering phenomenon, and a wide host range. The oriental fruit fly lays its eggs inside mature fruit. After the fruit is damaged by the oriental fruit fly, insect holes are created, rendering the fruit unsaleable. Simultaneously, the hatched larvae feed on the fruit pulp, causing fruit rot and drop, resulting in reduced star fruit yield.

[0003] Chemical control is currently the main method for eliminating the citrus fruit fly, but pesticide resistance is a significant issue in agricultural disease control. Studies have shown that with the extensive use of insecticides, the citrus fruit fly has developed resistance to various pesticides such as organophosphates, pyrethroids, and abamectin. Furthermore, environmental pollution and pesticide residues are becoming increasingly serious, severely impacting fruit quality. Therefore, the development of safe and effective new insecticides is urgently needed.

[0004] Combining different insecticidal active ingredients is a common method for controlling resistant diseases. When different active ingredients are combined, they usually exhibit three types of combined effects: synergistic, additive, and antagonistic. In most cases, the combination exhibits an additive effect, and combinations that truly have a synergistic effect are rare, especially those with a very significant synergistic effect.

[0005] Oxazosulfyl is a novel benzoxazole broad-spectrum insecticide reported by Sumitomo Chemical Co., Ltd. of Japan, containing an ethanesulfonylpyridine structural fragment. CAS No.: 1616678-32-0, Molecular Formula: C 15 H 11 F3N2O5S2, relative molecular mass: 420.383, structural formula as follows:

[0006]

[0007] Oxazolidinone has a novel structure, containing both a benzoxazole fragment and a sulfonylpyridine fragment. The benzoxazole fragment is found in herbicides such as oxazolidinone and oxazolidinyl chlorpyrifos, while the sulfonylpyridine fragment is widely found in sulfonylurea herbicides. Current technology reports that oxazolidinone is active against Hemiptera, Lepidoptera, Diptera, Coleoptera, and Orthoptera, and can be used to control various crop pests such as planthoppers, stem borers, flea beetles, codling moths, thrips, cutworms, and fruit flies. However, as an insecticide, long-term use of a single component inevitably carries a high risk of resistance development.

[0008] The inventors used a cotton ball feeding method to determine the synergistic effect of oxazolidinone combined with existing insecticidal active ingredients on the fruit fly *Bactrocera dorsalis*. They found that oxazolidinone, when combined with tetrazolium or fipronil at different mass ratios, exhibited a synergistic effect in killing *Bactrocera dorsalis*. No related reports on such combinations have been found to date. Summary of the Invention

[0009] The purpose of this invention is to provide an active insecticide for controlling the oriental fruit fly (Bactrocera dorsalis), in order to solve the problem that the oriental fruit fly has developed resistance to different insecticides.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] An active insecticide comprising an active ingredient and an auxiliary ingredient, wherein the active ingredient is a compound of oxazolidinone and tetrazolium or fipronil; the mass ratio of oxazolidinone to tetrazolium is 1-30:20-1; the mass ratio of oxazolidinone to fipronil is 1-10:10-1.

[0012] Furthermore, the auxiliary ingredients are selected from one or more of dispersants, wetting agents, solvents, cosolvents, inert fillers, disintegrants, thickeners, film-forming agents, penetrants, defoamers, antifreeze agents, preservatives, pH adjusters, synergists, and warning colors.

[0013] Furthermore, the mass of the active ingredient accounts for 5-55% of the total mass of the active insecticide.

[0014] The present invention also provides the application of the aforementioned active insecticide in the control of star fruit fly (Bactrocera dorsalis).

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) This invention used the cotton ball feeding method to determine the synergistic effect of oxazolidinone combined with tetrazolium or fipronil on the fruit fly *Bactrocera dorsalis*. It was found that oxazolidinone and tetrazolium or fipronil exhibited a synergistic effect in killing *Bactrocera dorsalis* at different mass ratios. Compared with single-component formulations, this method can improve the control effect on *Bactrocera dorsalis*, reduce pesticide usage, lower pesticide residues, mitigate environmental pollution, and contribute to the green, healthy, and sustainable development of the star fruit industry.

[0017] (2) Compared with the use of oxazolidinone alone, the active insecticide of the present invention can reduce the risk of resistance and delay the emergence and development of insecticide resistance in pests. Detailed Implementation

[0018] The technical solution of this invention patent will be clearly and completely described below.

[0019] Example

[0020] 1. Test insect source

[0021] Fruit flies of the oriental fruit were collected from star fruit orchards and fed to a stable population for more than 10 generations in the laboratory. Two-day-old adults from the same batch were selected as the test insect source.

[0022] 2. Test reagents

[0023] 98% oxazolidinyl sulfadiazine technical grade (Shanghai Yuanxi Biotechnology Co., Ltd.), 90% tetrazolium acetamiprid technical grade (Bayer AG), 99% fipronil technical grade (Hubei Xinkang Pharmaceutical Chemical Co., Ltd.)

[0024] 3. Test Methods

[0025] The toxicity of oxazolidinone, tetrazolium, fipronil and their mixtures to the starfruit fruit fly was determined using the cotton ball feeding method.

[0026] The test agent was dissolved in methyl sulfoxide and then diluted with 10% honey solution (solvent being 0.1% Tween-80 aqueous solution) to prepare a single-agent stock solution. The single agent was diluted with 10% honey solution (solvent being 0.1% Tween-80 aqueous solution) in equal proportions to form 7 mass concentration gradients. Then the toxicity of the single agent to the starfruit fly was determined.

[0027] Based on the single-agent toxicity test, multiple formulations were set up. Each formulation was diluted with 10% honey solution (0.1% Tween-80 aqueous solution) in equal proportions to form 7 mass concentration gradients. Then the toxicity of each formulation to the starfruit fly was determined.

[0028] The specific method for determining the toxicity of single-agent and mixed formulations is as follows: After thoroughly soaking sterilized defatted cotton balls in the test solution, remove them and place them in a 250mL Erlenmeyer flask after the solution stops dripping. Inoculate each flask with 10 adult insects (male to female ratio 1:1) starved for 12 hours. A blank control is provided using a 10% honey solution (solvent: 0.1% Tween-80 aqueous solution). Each treatment is repeated three times. After inoculating the adult insects, seal the Erlenmeyer flask with a single layer of medical gauze and place it in an artificial climate chamber at a temperature of (25±1)℃, relative humidity of 65±5%, and a photoperiod of 14L / 10D.

[0029] The mortality of the test insects was observed 48 hours after treatment. The total number of insects and the number of dead insects in each treatment were recorded, and the corrected mortality rate for each treatment was calculated. A linear regression was performed with the logarithm of the pesticide concentration as x and the corrected mortality rate probability as y to obtain the toxicity regression equation and the LC50 of the pesticide on the tested pests. 50 value.

[0030]

[0031] In the above formula: P -- mortality rate, in %; K -- number of dead insects; N -- total number of insects treated.

[0032]

[0033] In the above formula: P1 -- corrected mortality rate, in %; P t --Treatment mortality rate, in %; P0--Control mortality rate, in %.

[0034] 4. Data Analysis

[0035] The co-toxicity coefficient (CTC) was calculated using Sun Yunpei's co-toxicity coefficient method, and the combined effect of the compound combination on the tested strains was evaluated based on the CTC value: CTC≤80 indicates antagonistic effect, 80<CTC<120 indicates additive effect, and CTC≥120 indicates synergistic effect. The results are shown in Table 1-2.

[0036] Table 1. Toxicity test results of the combination of oxazolidinone and tetrazolium in the fruit fly citrus.

[0037]

[0038] Table 1 shows that within a mass ratio range of 1-30:20-1, the combination of oxazolidinone and tetrazolium acetamiprid exhibits a synergistic effect in controlling the oriental fruit fly. This indicates that the combination of oxazolidinone and tetrazolium acetamiprid in this invention can improve the control effect against the oriental fruit fly, reduce pesticide usage, lower pesticide residues, and mitigate environmental pollution.

[0039] Table 2. Toxicity test results of the combination of oxazolidinone and fipronil in the fruit fly citrus.

[0040]

[0041] Table 2 shows that within a mass ratio range of 1-10:10-1, the combination of oxazolidinone and fipronil exhibits a synergistic effect in controlling the oriental fruit fly. This indicates that the combination of oxazolidinone and fipronil in this invention can improve the control effect against the oriental fruit fly, reduce pesticide usage, lower pesticide residues, and mitigate environmental pollution.

[0042] This invention used a cotton ball feeding method to determine the synergistic effect of oxazolidinone combined with tetrazolium or fipronil on the fruit fly *Bactrocera dorsalis*. The results showed that oxazolidinone and tetrazolium or fipronil exhibited a synergistic effect in controlling *Bactrocera dorsalis* at different mass ratios. Compared with single-component formulations, this method can improve the control efficacy against *Bactrocera dorsalis*, reduce pesticide usage, lower pesticide residues, mitigate environmental pollution, and contribute to the green, healthy, and sustainable development of the star fruit industry.

Claims

1. An active insecticide, characterized in that, The insecticide includes an active ingredient and an auxiliary ingredient, wherein the active ingredient is a compound of oxazolidinone and tetrazolium amide; the mass ratio of oxazolidinone to tetrazolium amide is 1-30:20-1.

2. The active insecticide according to claim 1, characterized in that, The auxiliary ingredients are selected from one or more of the following: dispersants, wetting agents, solvents, cosolvents, inert fillers, disintegrants, thickeners, film-forming agents, penetrants, defoamers, antifreeze agents, preservatives, pH adjusters, synergists, and warning colors.

3. The active insecticide according to claim 1, characterized in that, The active ingredient comprises 5-55% of the total mass of the active insecticide.

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