Biological pesticide for preventing and treating citrus red mite

Abstract

The present application belongs to the technical field of pesticides, and particularly relates to a biological pesticide for preventing and treating citrus red mite. The biological pesticide is prepared by compounding emodin with abamectin or osthole. When emodin is combined with abamectin or osthole, a synergistic effect is exhibited on the citrus red mite, the prevention and treatment effect on the citrus red mite can be improved, the problems caused by long-term use of the same type of pesticide or the same pesticide can be alleviated, the generation and development of the drug resistance of the citrus red mite can be delayed, and support is provided for the comprehensive management of the drug resistance. In addition, emodin, abamectin and osthole are all biological pesticide components, are environment-friendly and green, and can provide support for developing the biological pesticide for preventing and treating the citrus red mite.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically relating to a biological pesticide for controlling citrus red spider mites. Background Technology

[0002] The citrus red spider mite (Tetranychus cinnbarinus) is a pest belonging to the Tetranychus family of the Acari class, subclass Acari, and is one of the major pests in citrus production management. Citrus red spider mites damage young shoots, leaves, and fruit peels by sucking sap, with leaf damage being the most severe. Affected leaves develop grayish-white spots; in severe cases, the entire leaf turns grayish-white, and may even lead to leaf and fruit drop, seriously affecting the vigor and yield of citrus trees.

[0003] Chemical control has always been the primary method for controlling citrus red spider mites, with commonly used agents including abamectin, spirodiclofen, pyridaben, and diflubenzuron. However, in production, repeated or excessive use, long-term or continuous use of the same type of agent, or even the same agent, has led to the rapid development of pesticide resistance in citrus red spider mites, resulting in low efficacy or even ineffectiveness. Therefore, selecting agents with synergistic effects is of great importance for controlling citrus red spider mites. In addition, for some citrus varieties, such as tangerine peel, tea branch mandarin orange, and kumquat, whose peels can be used medicinally or eaten fresh, low-residue, environmentally friendly biological pesticides should be used.

[0004] Avermectin is a sixteen-membered macrocyclic lactone biopesticide with insecticidal, acaricidal, and nematicidal activities, produced by the fermentation of *Streptomyces avermitilis*. Avermectin has stomach poison and contact action against mites and insects. Its mechanism of action differs from that of general insecticides in that it interferes with neurophysiological activity, stimulating the release of γ-aminobutyric acid (GABA), which inhibits nerve conduction in arthropods. Adult mites, nymphs, and insect larvae exhibit paralysis upon contact with avermectin, becoming inactive and refusing to feed, and die after 2-4 days.

[0005] Osthol is a plant-derived pesticide extracted from the fruit of *Cnidium monnieri*, an annual herbaceous plant belonging to the Apiaceae family. It possesses the pesticide-active gene—isoprene—and exhibits unique insecticidal and antibacterial activities. Osthol primarily acts as a contact insecticide, with secondary stomach poisoning. The pesticide is absorbed through the insect's body surface, acting on the insect's nervous system, causing non-functional muscle contractions and ultimately leading to exhaustion and death. It shows good contact activity against various pests such as cabbage caterpillars, tea geometrid moths, cotton bollworms, and various aphids.

[0006] In the prior art, the quinone compound emodin (CAS: 518-82-1) is disclosed to have good insecticidal activity against brown planthoppers. Studies have found that the insecticidal mechanism of emodin may be related to the inhibitory activity of AChE and GST. By inhibiting the activity of the above two enzymes, it causes the insect's nerve conduction and motor function to be impaired and the insect's detoxification function to be inactivated, thereby leading to the death of brown planthoppers.

[0007] Currently, there are no reports of combining emodin with avermectin or osthol. Summary of the Invention

[0008] The purpose of this invention is to provide a biological pesticide for controlling citrus red spider mites, in order to solve the problem that repeated, excessive, long-term, and continuous use of the same type of pesticide, or even the same pesticide, in production leads to the rapid development of pesticide resistance in citrus red spider mites, resulting in low control efficacy or even failure.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A biological pesticide, wherein the biological pesticide is a compound of emodin and avermectin or osthol.

[0011] More specifically, the mass ratio of emodin to avermectin is 1-20:20-1.

[0012] More specifically, the mass ratio of emodin to osthol is 1-7:15-1.

[0013] More specifically, the mass ratio of emodin to osthol is 1:7.

[0014] The present invention also provides the application of the aforementioned biological pesticide in the control of citrus red spider mites.

[0015] The present invention also provides a biological pesticide formulation, wherein the biological pesticide formulation is prepared by using the biological pesticide as the active ingredient and supplementing it with auxiliary ingredients permitted to be added in pesticide science.

[0016] More specifically, the formulation of the biological pesticide includes granules.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) When the present invention combines emodin with avermectin or osthol, it exhibits a synergistic effect on citrus red spider mites, which can improve the control effect on citrus red spider mites, help alleviate the problems caused by long-term use of the same type of pesticide or the same pesticide, and delay the emergence and development of pesticide resistance in citrus red spider mites, thus providing support for integrated management of pesticide resistance.

[0019] (2) The rhein, abamectin and osthol of this invention are all biological pesticide components, which are environmentally friendly and green, and can provide support for the development of biological pesticides to control citrus red spider mites. Detailed Implementation

[0020] The technical solution of this invention patent will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0021] Example Indoor biological testing experiments

[0022] 1. Test reagents

[0023] 95% emodin technical grade (CAS: 518-82-1), 94% avermectin technical grade, 98% osthol technical grade.

[0024] After dissolving the original drug, dilute it with 0.1% Tween-80 aqueous solution to prepare a single-dose stock solution. Based on the results of the preliminary test, set up multiple formulations. Then, dilute each single-dose stock solution and each formulation mixture with 0.1% Tween-80 aqueous solution to prepare 5 mass concentration gradients for later use.

[0025] 2. Test insect source

[0026] Citrus red spider mites were collected from citrus orchards. After being brought back to the laboratory and reared for five generations, female adult mites of uniform size were selected as test subjects.

[0027] 3. Test Methods

[0028] The bioactivity of single and mixed pesticides against citrus red spider mites was determined using the slide immersion method recommended by the Food and Agriculture Organization of the United Nations. Specifically, a 1cm wide and 2.5cm long double-sided tape was attached to one end of a glass slide. A brush was moistened and used to pick up the test insects, adhering their backs to the tape. Three rows of 10 insects per slide were placed on each slide, for a total of 30 insects. The slides were placed in a container lined with a damp sponge and incubated at 25±1℃ for 2 hours. Afterward, the slides were examined under a microscope, and dead or injured individuals were removed, replenishing the slides to 30 insects each. The slides containing the test insects were then immersed in the pesticide solution, gently shaken for 5 seconds, and then removed. Excess pesticide solution was absorbed with absorbent paper. Each treatment was repeated four times, with a 0.1% Tween-80 aqueous solution serving as a blank control.

[0029] The tested insect sources were transferred to an artificial incubator at 25±1℃, relative humidity of 75±5%, and photoperiod of 16L / 8D. After 48 hours, the mortality of the tested insects was investigated (death was defined as the mite's legs not moving when touched with a brush). 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.

[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] Regression analysis was performed on the logarithmic values ​​of the drug concentrations and the corrected mortality odds values ​​for each treatment to calculate the LC-1 of each treatment. 50 The co-toxicity coefficient (CTC value) of the mixture was calculated using the Sun Yunpei method.

[0036] The combined effects of the drugs were evaluated based on the calculated co-toxicity coefficient (CTC): 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.

[0037] Table 1. Results of indoor bioactivity assays of emodin and avermectin combination on citrus red spider mites.

[0038]

[0039] Table 1 shows that when emodin and avermectin are combined in a mass ratio of 1-20:20-1, the co-toxicity coefficients against citrus red spider mites range from 125.697 to 374.027, all greater than 120, indicating a synergistic effect. This demonstrates that the combination of emodin and avermectin in this invention can improve the control effect against citrus red spider mites.

[0040] Table 2. Results of indoor bioactivity assays of emodin and osthol combined with citrus red spider mite.

[0041] Drug Name and Proportion <![CDATA[LC 50 (mg / L)]]> ATI TTI CTC emodin 147.862 100.000 -- -- Cnidium monnieri 15.069 981.233 -- -- Emodin 1: Osthol 15 9.587 1542.318 926.156 166.529 Emodin 1: Osthol 7 3.604 4102.719 871.079 470.993 Emodin 1: Osthol 3 7.849 1883.832 760.925 247.571 Emodin 1: Osthol 1 18.476 800.292 540.616 148.033 Emodin 3: Osthol 1 36.794 401.864 320.308 125.462 Emodin 7: Osthol 1 42.663 346.581 210.154 164.918

[0042] Table 2 shows that when emodin and osthol are combined in a mass ratio of 1:7:15:1, the co-toxicity coefficients against citrus red spider mites range from 125.462 to 470.993, all greater than 120, demonstrating a synergistic effect. Especially when the mass ratio is 1:7, the co-toxicity coefficient reaches 470.993, showing the most significant synergistic effect. This indicates that the combination of emodin and osthol in this invention can improve the control effect against citrus red spider mites.

[0043] In summary, when emodin is combined with avermectin or osthol, the present invention exhibits a synergistic effect against citrus red spider mites, which can improve the control effect of citrus red spider mites, help alleviate the problems caused by long-term use of the same type of pesticide or the same pesticide, and delay the emergence and development of pesticide resistance in citrus red spider mites, thus providing support for pesticide resistance management.

Claims

1. A biological pesticide, said biological pesticide being used to control citrus red spider mites. Tetranychus cinnbarinus Its characteristics are, The biological pesticide is a compound of emodin and abamectin, wherein the mass ratio of emodin to abamectin is 1-20:20-1.

2. The biological pesticide according to claim 1 for controlling citrus red spider mites. Tetranychus cinnbarinus Applications in [the field].

3. A biological pesticide formulation for controlling citrus red spider mites. Tetranychus cinnbarinus Its characteristics are, The biological pesticide formulation is prepared using the biological pesticide of claim 1 as the active ingredient, supplemented with auxiliary ingredients permitted to be added in pesticide science.

4. The biological pesticide formulation according to claim 3, characterized in that, The formulations of the biological pesticides include granules.

Images