Biopesticide for preventing and treating citrus thrips

Abstract

The invention belongs to the technical field of biopesticides, and particularly relates to a biopesticide for preventing and treating citrus thrips. The invention relates to a biopesticide. Active ingredients of the biopesticide are formed by compounding ligustilide and rotenone, or the active ingredients of the composition are formed by compounding ligustilide and sophocarpidine. The ligustilide is compounded with the rotenone and the sophocarpidine respectively, the combined action effect of the compounded combination on the citrus thrips is measured through a leaf tube medicine membrane method, and the result shows that when the ligustilide and the rotenone are compounded according to the mass ratio of (1-15): (15-1), the synergistic interaction effect on the citrus thrips is achieved; when ligustilide and sophocarpidine are compounded according to the mass ratio of (1-9): 1, the ligustilide and sophocarpidine have a synergistic effect on the citrus thrips. According to the present invention, the ligustilide and the rotenone or the sophocarpidine are compounded so as to improve the prevention and control effect on the citrus thrips and delay the development of the drug resistance of the pests, such that the support can be provided for the research and development of the biopesticide for preventing and controlling the citrus thrips.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological pesticides for prevention and treatment, and particularly relates to a biological pesticide for preventing and treating citrus thrips. BACKGROUND

[0002] At present, chemical agents are the main means for preventing and treating citrus thrips (Scirtothrips citri). Scirtothrips citri However, with the unscientific use of chemical agents, such as long-term use of a single agent, the resistance of citrus thrips gradually accumulates, resulting in a decreasing effect of existing chemical agents on the prevention and treatment of citrus thrips year by year. Although increasing the dosage of the agent can improve the control effect on pests, it will exacerbate the development of pest resistance and also lead to excessive pesticide residues and environmental pressure. Therefore, it is necessary to develop new agents for preventing and treating citrus thrips.

[0003] Ligustilide (CAS: 4431-01-0), also known as thujone, is the main active ingredient of the volatile oil of the Umbelliferae plant Angelica sinensis. Currently, ligustilide is mainly used in the medical field, but with the gradual deepening of research, it has been found to have activity in killing agricultural pests. For example, CN115777711B uses leaf immersion method to determine the toxicity of ligustilide and indoxacarb to 3rd instar larvae of Spodoptera littoralis, and the results show that the insecticidal activity of ligustilide is significantly better than that of indoxacarb, with an LC 50 of 3.5118 mg / L, which has good insecticidal effect and can be used to develop biological pesticides for preventing and treating agricultural pests. However, the control effect of a single agent on target pests is limited, and through the reasonable compounding of different agents, the selection of a compounded combination with synergistic effect can improve the control effect and also delay the development of resistance of target pests. Therefore, it is of great significance to develop a compounded combination of ligustilide.

[0004] Currently, there is no related report on the compounding of ligustilide and rotenone, or ligustilide and sophoridine. SUMMARY

[0005] The purpose of the present application is to provide a biological pesticide for preventing and treating citrus thrips, which has synergistic effect between active ingredients and can improve the control effect on citrus thrips, thereby providing support for the research and development of biological pesticides for preventing and treating citrus thrips.

[0006] To achieve the above purpose, the present application provides the following technical solutions: A biological pesticide, whose active ingredients are compounded from ligustilide and rotenone; or whose effective ingredients are compounded from ligustilide and sophoridine.

[0007] As a preference, the mass ratio of ligustilide to rotenone in the compounded combination is 1-15:15-1.

[0008] Preferably, the composite mass ratio of ligustilide to matrine is 1-9:1.

[0009] Preferably, the composite mass ratio of ligustilide to matrine is 6:1.

[0010] The present invention also provides the biological pesticide for preventing and controlling citrus thrips Scirtothrips citri Application in.

[0011] The present invention also provides a biopesticide preparation, which includes the active ingredient of the biopesticide.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention combines ligustilide with rotenone and matrine, respectively, and determines the combined effects of the combinations on citrus thrips by using the leaf tube pellicle method. The results show that when ligustilide and rotenone are combined in a mass ratio of 1-15:15-1, they exhibit a synergistic effect on citrus thrips; and when ligustilide and matrine are combined in a mass ratio of 1-9:1, they exhibit a synergistic effect on citrus thrips. This indicates that the combination of ligustilide with rotenone or matrine can improve the control effect on citrus thrips and delay the development of pest resistance, thereby providing support for the research and development of biological pesticides for controlling citrus thrips.

[0013] (2) The active ingredients of the biological pesticide for controlling citrus thrips of the present invention are compounded from biological pesticides, are green and environmentally friendly, and can effectively alleviate environmental pressure. DETAILED DESCRIPTION

[0014] The following is a clear and complete description of the technical solution of the patent of this invention.

[0015] 1. Materials and Methods 1.1 Test agents 98% ligustilide technical (source leaf biological), 92.8% rotenone technical (extracted from rotenone root), 98% matrine technical (source leaf biological).

[0016] The test agent was dissolved in an organic solvent and then diluted with distilled water containing 0.05% Triton X-100 to prepare a high-concentration single-dose stock solution. According to the results of the previous test, multiple groups of ratios were set up, and each single-dose stock solution and each group of mixed agents were diluted with distilled water containing 0.05% Triton X-100 to form 6 mass concentration gradients. The above agents were prepared and used immediately.

[0017] 2. Test pests Citrus thrips were collected from citrus plantations and reared for six generations on fresh, clean, pesticide-free citrus leaves in an artificial climate chamber at 25±1℃, relative humidity (RH) 65±5%, and a photoperiod of 16 L / 8 D. Second-instar nymphs with the same physiological state were selected as the test subjects.

[0018] 3. Test methods The leaf-tube pellicle method was used. Fill a centrifuge tube with the pesticide solution, let it sit for 4 hours, then discard the solution. Open the tube cap and allow it to air dry. Holes were then made in the bottom and cap of the tube, with the hole diameter set to prevent the test pest from escaping. Fresh, clean, unexposed citrus leaves were collected and punched with a hole punch to create 1-cm-diameter leaf discs. These discs were soaked in the pesticide solution for 10 seconds, removed, air-dried, and placed in centrifuge tubes treated with the corresponding concentration of pesticide solution, one disc per tube. Five test pests were then introduced into each centrifuge tube. Each treatment was repeated four times, with four centrifuge tubes forming one replicate. A blank control was used, containing 0.05% Triton X-100 in distilled water.

[0019] Then, the tubes were capped and placed under conditions of 25±1°C, relative humidity 65±5%), and a photoperiod of 16 L / 8D for observation. After 48 hours, the mortality of the test insects was investigated. Insects that could not crawl after being lightly touched with a brush tip were considered dead. The total number of insects and the number of dead insects in each treatment were recorded, and the corrected mortality rate of each treatment was calculated. The logarithmic value of the concentration of the pesticide and the corrected mortality probability value were then regressed using DPS software to calculate the LC value of each treatment. 50 .

[0020]

[0021] In the above formula: P --Mortality rate, in%; K --The number of dead insects; N --Total number of insects treated.

[0022]

[0023] In the above formula: P 1--Adjusted mortality rate, unit is %; P t --Treatment mortality rate, in%; P 0--Blank control mortality rate, unit is %.

[0024] 4. Drug Evaluation The Sun Yunpei method was used to calculate the co-toxicity coefficient (CTC value) of the mixture. According to the joint effect classification standard: a co-toxicity coefficient (CTC) ≥ 120 indicates a synergistic effect; a co-toxicity coefficient (CTC) ≤ 80 indicates an antagonistic effect; and a co-toxicity coefficient (CTC) 80 < 120 indicates an additive effect.

[0025]

[0026] In the above formula: ATI - the observed toxicity index of the mixture; S - the LC50 of the standard agent 50 in mg / L; M - the LC50 of the mixture 50 in mg / L.

[0027]

[0028] In the above formula: TTI - the theoretical toxicity index of the mixture; TI A - the toxicity index of agent A; P A - the percentage content of agent A in the mixture, in percentage (%); TI B - the toxicity index of agent B; P B - the percentage content of agent B in the mixture, in percentage (%).

[0029]

[0030] In the above formula: CTC - the coefficient of joint toxicity; ATI - the observed toxicity index of the mixture; TTI - the theoretical toxicity index of the mixture.

[0031] 5. Results The results are shown in Tables 1-2.

[0032] Table 1 Joint action results of ligustilide and rotenone on citrus thrips Drug name and ratio LC 50 (mg / L) ATI TTI CTC Ligustilide 4.729 100.000 -- -- Rotenone 7.386 64.027 -- -- Ligustilide 1: Rotenone 15 5.689 83.125 66.275 125.425 Ligustilide 1: Rotenone 9 4.882 96.866 67.624 143.242 Ligustilide 1: Rotenone 3 3.129 151.135 73.020 206.977 Ligustilide 1: Rotenone 1 4.426 106.846 82.013 130.279 Ligustilide 3: Rotenone 1 2.954 160.088 91.007 175.908 Ligustilide 9: Rotenone 1 3.603 131.252 96.403 136.150 Ligustilide 15: Rotenone 1 3.942 119.964 97.752 122.724 As shown in Table 1, when ligustilide and rotenone are compounded at a mass ratio of 1-15:15-1, the coefficient of joint toxicity on 2nd instar nymphs of citrus thrips is greater than 120, showing synergistic effect.

[0033] Table 2 Joint action results of ligustilide and matrine on citrus thrips Drug name and ratio <![CDATA[LC 50 (mg / L)]]> ATI TTI CTC Ligustilide 4.729 100.000 -- -- matrine 12.562 37.645 -- -- Ligustilide 1: Matrine 1 3.672 128.785 68.823 187.127 Ligustilide 3: Matrine 1 1.594 296.675 84.411 351.464 Ligustilide 9: Matrine 1 2.982 158.585 93.765 169.131 Ligustilide 15: Matrine 1 5.073 93.219 96.103 96.999 As shown in Table 2, when ligustilide and matrine are compounded at a mass ratio of 1-9:1, the coefficient of joint toxicity on 2nd instar nymphs of citrus thrips is greater than 120, showing synergistic effect.

[0034] In summary, the present invention combines ligustilide with rotenone and matrine, respectively, and determines the combined effects of the combinations against citrus thrips using the leaf tube pellicle method. The results show that ligustilide and rotenone exhibit a synergistic effect against citrus thrips when combined in a mass ratio of 1-15:15-1, and ligustilide and matrine exhibit a synergistic effect against citrus thrips when combined in a mass ratio of 1-9:1. This indicates that the combination of ligustilide with rotenone or matrine can improve the control effect against citrus thrips and delay the development of pest resistance, thereby providing support for the research and development of biopesticides for controlling citrus thrips.

Claims

1. A biological pesticide, characterized in that: Its active ingredients are a combination of ligustilide and rotenone; Or its active ingredient is a combination of ligustilide and matrine.

2. The biopesticide according to claim 1, characterized in that The composite mass ratio of ligustilide to rotenone is 1-15:15-1.

3. The biopesticide according to claim 1, characterized in that The composite mass ratio of ligustilide to matrine is 1-9:

1.

4. The biopesticide according to claim 3, characterized in that The composite mass ratio of ligustilide to matrine is 6:

1.

5. The biopesticide according to any one of claims 1 to 4 for controlling citrus thrips Scirtothrips citri Application in.

6. A biopesticide formulation, characterized in that: The biopesticide preparation comprises the active ingredient of the biopesticide according to any one of claims 1 to 4.