Application of coumarin compounds in prevention and treatment of citrus huanglongbing or killing of psyllids

Abstract

The application provides application of a coumarin compound in prevention and treatment of citrus Huanglongbing or killing of psyllospora citri, and belongs to the technical field of plant disease prevention and treatment. The application takes the citrus Huanglongbing medium pest psyllospora citri as a research object, systematically evaluates biological activity of the coumarin compound on the psyllospora citri, and the result shows that the coumarin compound can effectively kill the psyllospora citri. The application not only provides more choices for the plant source pesticide with good prevention and treatment effect on the psyllospora citri, but also has reference significance for formulating a field resistance management strategy of the psyllospora citri, simultaneously provides a train of thought for developing a high-efficiency prevention and treatment technology of the psyllospora citri, and therefore has important theoretical significance and application prospect.

Description

[0001] This invention is a divisional application of application number 202311414569.8 filed on October 30, 2023, entitled "Application of coumarin compounds in the prevention and control of citrus Huanglongbing or the killing of psyllids". Technical Field

[0002] This invention belongs to the field of plant disease control technology, and in particular relates to the application of a coumarin compound in the control of citrus Huanglongbing or the killing of psyllids. Background Technology

[0003] Huanglongbing (HLB) is the most devastating disease of citrus, often referred to as the "cancer" of citrus, and a leading cause of death in the global citrus industry. The citrus psyllid (Diaphorina citri) is the primary vector for HLB transmission, and strict control of this insect is crucial for HLB control both domestically and internationally. However, the frequent and unscientific use of chemical pesticides has significantly increased the cost of citrus production, while also causing problems such as pesticide resistance and pesticide residues in the psyllid. The widespread use of neonicotinoid insecticides in citrus-producing regions worldwide has exacerbated the problem of psyllid resistance. For example, studies have shown that citrus psyllids in Michoacán, Mexico, have developed very strong resistance to imidacloprid, exhibiting high levels of resistance. Therefore, exploring new approaches or new pesticide targets to address the problem of pesticide resistance in citrus psyllids is particularly urgent.

[0004] Coumarin compounds are a large class of phenolic substances found in plants, composed of a benzo[a]-α-pyranone core. Coumarin compounds are widely used in the medical field, possessing anticancer, antibacterial, anti-inflammatory, and antioxidant activities. In recent years, scholars both domestically and internationally have discovered that some natural coumarin compounds possess insecticidal, acaricidal, antibacterial, and herbicidal activities, and some natural coumarin compounds have been successfully developed into pesticides for agricultural production. For example, studies have reported that coumarin compounds (imperatorin, isofennelolide, and isoimperatorin) have strong contact toxicity against Culex pipiens quinquefolius and Aedes aegypti; daphne has antifeedant and contact toxic effects on various aphids; scopolamine can effectively inhibit the growth of dust moths and also has antifeedant effects. Furthermore, scopolamine has multiple activities against Tetranychus carmine, including contact toxicity, systemic activity, and oviposition inhibition, and under long-term indoor stress, Tetranychus carmine develops almost no resistance. In summary, the highly efficient and broad-spectrum insecticidal (acaricidal) activity exhibited by coumarins makes them potential for development into novel insecticides (acaricides). However, current research on coumarins mainly focuses on in-depth exploration of their medical activities, with relatively few reports on their insecticidal activities. The bioactivity of coumarins against the citrus psyllid, a vector pest of Huanglongbing (HLB), remains unclear. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide the application of coumarin compounds in the prevention and control of citrus Huanglongbing (HLB) or the killing of psyllids, wherein the coumarin compounds can significantly kill psyllids, thereby effectively preventing and controlling citrus HLB.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an application of coumarin compounds in the prevention and control of citrus Huanglongbing (HLB), wherein the coumarin compounds are one or more selected from artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

[0007] This invention provides the application of coumarin compounds in the preparation of products for the prevention and control of citrus Huanglongbing (HLB). The coumarin compounds are one or more selected from artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

[0008] This invention provides the application of coumarin compounds in killing psyllids, wherein the coumarin compounds are one or more selected from artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

[0009] This invention provides the application of coumarin compounds in the preparation of products for killing psyllids, wherein the coumarin compounds are one or more selected from artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

[0010] Preferably, the coumarin compound is one or more of 7-hydroxycoumarin, daphne, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

[0011] Preferably, the concentration of the coumarin compound is 0.1~2 mg / mL.

[0012] Preferably, the product includes pesticides or reagents.

[0013] Preferably, the psyllid includes the citrus psyllid.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention provides the application of coumarin compounds in the control of citrus Huanglongbing (HLB) or the killing of psyllids. Using the citrus psyllid, a vector pest of HLB, as the research object, this invention systematically evaluates the bioactivity of coumarin compounds against the citrus psyllid. The results show that coumarin compounds can effectively kill the citrus psyllid. This invention not only provides a new option for plant-derived pesticides with good control effects on citrus psyllids, but also has reference value for the formulation of field resistance management strategies for psyllids. Furthermore, it provides new ideas for the development of efficient control technologies for citrus psyllids, thus possessing significant theoretical significance and application prospects. Attached Figure Description

[0015] Figure 1 The effect of coumarin compounds on the insecticidal activity of citrus psyllids.

[0016] Figure 2 The effect of different concentrations of 7-methylcoumarin on the insecticidal activity of citrus psyllids. Detailed Implementation

[0017] This invention provides an application of coumarin compounds in the prevention and control of citrus Huanglongbing (HLB).

[0018] This invention provides the application of coumarin compounds in the preparation of products for the prevention and control of citrus Huanglongbing (HLB).

[0019] This invention provides the application of coumarin compounds in the killing of psyllids.

[0020] This invention provides the application of coumarin compounds in the preparation of products for killing psyllids.

[0021] In this invention, the above-mentioned application uses coumarin compounds as active ingredients. Studies have shown that the coumarin compounds of this invention can effectively kill psyllids, especially citrus psyllids, thereby achieving the purpose of preventing and controlling citrus Huanglongbing (HLB).

[0022] In this invention, the coumarin compound is preferably one or more selected from coumarin, artemisinin, 7-hydroxycoumarin, daphne, 7-methylcoumarin, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 7-amino-4-methylcoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin; more preferably, the coumarin compound is one or more selected from coumarin, 7-methylcoumarin, and 7-amino-4-methylcoumarin; even more preferably, the coumarin compound is 7-methylcoumarin. This invention utilizes 7-methylcoumarin to kill psyllids, exhibiting the highest insecticidal activity and a psyllid mortality rate as high as 73.23%. The psyllids preferably include citrus psyllids.

[0023] In this invention, the concentration of the coumarin compound is preferably 0.1~2 mg / mL, more preferably 0.3~1.5 mg / mL.

[0024] In this invention, the product includes pesticides or reagents. The pesticides or reagents use coumarin compounds as active ingredients, including one or more of the following: coumarin, artemisinin, 7-hydroxycoumarin, daphne, 7-methylcoumarin, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 7-amino-4-methylcoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin. The pesticide formulations include suspension concentrates, water-dispersible granules, wettable powders, emulsifiable concentrates, or granules.

[0025] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0026] Example 1 (1) Effects of coumarin compounds on the insecticidal activity of citrus psyllids: The coumarin compounds are coumarin, artemisinin, 7-hydroxycoumarin, daphne, 7-methylcoumarin, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 7-amino-4-methylcoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, or 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

[0027] Preparation of coumarin compound solutions: Weigh 0.1 g of the above-mentioned coumarin compound technical grade and dissolve it in 1 mL of acetone to prepare a stock solution of 100 mg / mL. Add 0.1 mL of 0.1% Tween 20 (v / v) and then dilute with 98.9 mL of pure water to 1 mg / mL. Vortex the solution to fully dissolve the coumarin compound.

[0028] Preparation of blank solution: Add 0.1 mL of 0.1% Tween 20 (v / v) and 98.9 mL of pure water to 1 mL of acetone, and vortex to fully dissolve the blank solution.

[0029] The insecticidal activity of coumarin compounds against citrus psyllids was detected by immersion method: 25 4th-5th instar citrus psyllid nymphs were picked and placed on the back of Murraya paniculata leaves. They were then immersed in either the above-mentioned 1 mg / mL coumarin compound solution or the blank solution (i.e., control group, CK) for 30 s and then transferred to clean Murraya paniculata leaves. The leaves were placed in a light incubator and the mortality was recorded at 24 and 48 h. Each experiment was set up with 3 biological replicates.

[0030] Figure 1 The results showed that after 24 h of treatment, coumarin, artemisinin, 7-hydroxycoumarin, daphne, 7-methylcoumarin, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 7-amino-4-methylcoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin all exhibited insecticidal activity against citrus psyllids, with a mortality rate of less than 40%. However, after 48 h of treatment, compared with 24 h of treatment, the insecticidal activity of the above coumarin compounds against citrus psyllids increased, with 7-methylcoumarin showing the highest insecticidal activity and a mortality rate as high as 73.23%.

[0031] (2) Toxicity determination of 7-methylcoumarin For the preparation of 1 mg / mL 7-methylcoumarin solution or blank solution, please refer to section (1) above. Then, dilute 1 mg / mL 7-methylcoumarin with pure water to 0.5, 0.25, 0.125, and 0.0625 mg / mL 7-methylcoumarin to obtain 1, 0.5, 0.25, 0.125, and 0.0625 mg / mL 7-methylcoumarin solutions, respectively.

[0032] Based on the above results, 7-methylcoumarin was selected for toxicity testing. Thirty 4th-5th instar citrus psyllid nymphs were collected and placed on the underside of Murraya paniculata leaves. They were then treated with 1, 0.5, 0.25, 0.125, and 0.0625 mg / mL 7-methylcoumarin or a blank solution (control group, CK) for 30 seconds. Afterward, they were transferred to clean Murraya paniculata leaves and placed in a light incubator. Mortality was recorded after 48 hours. The toxicity regression equation for the candidate coumarins was calculated using SPSS software, and the sublethal concentration and LC50 of 7-methylcoumarin in killing citrus psyllids were analyzed. 50 The measurement results are shown in Table 1.

[0033] Table 1. LC50 of 7-methylcoumarin in killing citrus psyllids 50 Measurement results

[0034] Figure 2 The results showed that the mortality rate of citrus psyllids gradually increased with increasing 7-methylcoumarin concentration. Table 1 shows the sublethal concentration (LC50) of 7-methylcoumarin compounds against citrus psyllids. 50 It was 0.3963 mg / mL.

[0035] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of coumarin compounds in the control of citrus Huanglongbing (HLB), characterized in that, The coumarin compounds are one or more of the following: artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

2. The application of coumarin compounds in the preparation of products for the prevention and control of citrus Huanglongbing (HLB), characterized in that, The coumarin compounds are one or more of the following: artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

3. The application of coumarin compounds in the control of psyllids, characterized in that, The coumarin compounds are one or more of the following: artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

4. The application of coumarin compounds in the preparation of products for killing psyllids, characterized in that, The coumarin compounds are one or more of the following: artemisinin, 7-hydroxycoumarin, daphne, 7,8-dimethyl-4-phenylcoumarin, xanthotoxin, 4-hydroxycoumarin, 6-hydroxycoumarin, 7-mercapto-4-methylcoumarin, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

5. The application according to any one of claims 1 to 4, characterized in that, The coumarin compounds are one or more of 7-hydroxycoumarin, daphne, and 3-(2-benzothiazolyl)-7-(diethylamino)coumarin.

6. The application according to any one of claims 1 to 4, characterized in that, The concentration of the coumarin compounds is 0.1~2 mg / mL.

7. The application according to claim 2 or 4, characterized in that, The products include pesticides or reagents.

8. The application according to claim 3 or 4, characterized in that, The psyllids include citrus psyllids.

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