Application of plant-derived compound coumestrol in the preparation of thrips insecticide

Abstract

The present invention provides the use of a plant-derived compound, coumestrol, in the preparation of a thrips insecticide, wherein the molecular formula of coumestrol is C 15 H8O5. The present invention mixes coumestrol with a surfactant, a filler, and one of insecticidal active compounds to prepare an insecticide, and sprays the insecticide containing coumestrol on the surface of cowpea pods to kill insects. The method develops a new use of the flavonoid compound coumestrol, and coumestrol is derived from plants, so the prepared insecticide has significant insecticidal effect and is environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of insecticides, and in particular to application of a plant-derived compound, coumestrol, in the preparation of a thrips insecticide. Background Art

[0002] Cowpea is an important legume crop in tropical and subtropical regions and a major source of plant protein. Due to the simple habitat and single structure of the planting area, cowpea suffers from serious insect pests during its growing period. Among them, thrips are the most important pest in field planting of cowpea, which can damage tender leaves, flowers and pods. After being infested, the leaves curl, the indefinite inflorescence cannot develop normally, and the formation of pods is seriously affected. The black tail symptoms of the pods are common, the pod length is generally shortened, the yield is greatly reduced, and the income of farmers is significantly affected.

[0003] Common Thrips Megalurothrips usitatus (Bagnall)], Flower Thrips[ Frankliniella intonsa (Trybom)] and western flower thrips [ Frankliniella occidentalis (Pergande)] is the main thrips that harm cowpea, among which the most serious and widespread is the common giant thrips. Thrips have strong reproductive capacity, fast reproduction speed, and serious overlapping generations. The frequent use of chemical pesticides to control them has led to an increase in the resistance of thrips year by year. This in turn forces an increase in the amount of pesticides used and an increase in the frequency of use. The result of the above is that the pesticide residues in cowpeas exceed the standard seriously, posing a major threat to food safety. The most representative case is the "poisonous cowpea" incident in Hainan. Therefore, it is urgent to develop an ecological prevention and control system for thrips. The development of new types of insecticides that are highly efficient, low-toxic, residue-free, non-toxic to crops, do not pollute the environment, and are safe for humans and animals has become an inevitable trend.

[0004] Plants are a natural treasure trove of bioactive compounds. At present, many plant-derived compounds have been found to have insecticidal activity, such as rotenone and azadirachtin. Plant-derived insecticides do not pollute the environment, are relatively safe for humans, livestock, crops, and the ecological environment, and insects are not likely to develop resistance to them. The use of plant-derived insecticides to carry out ecological control of pests is conducive to the healthy and sustainable development of agriculture; the purpose of the present invention is to develop a new use of the flavonoid compound coumestrol, that is, a new use in the control of agricultural pests thrips. Summary of the invention

[0005] The invention provides an application of a plant-derived compound, coumestrol, in preparing a thrips insecticide. The invention uses coumestrol from a plant as a main component and mixes it with a surfactant, a filler and one of insecticidal active compounds to prepare the insecticide. The insecticide containing coumestrol is sprayed on the surface of cowpea pods to kill insects. The insecticide is simple to prepare, has a significant insecticidal effect and is environmentally friendly. Coumestrol is a new application in killing thrips insects.

[0006] The specific technical solutions are as follows:

[0007] Application of coumestrol in the preparation of thrips insecticide, wherein the molecular formula of coumestrol is C 15 H8O 5， The chemical structure is shown in formula (1);

[0008]

[0009] Formula (1).

[0010] Furthermore, the thrips are Macrothrips, Western Flower Thrips and / or Flower Thrips.

[0011] Furthermore, the thrips are adults and / or nymphs.

[0012] Furthermore, the thrips insecticide is prepared by mixing coumestrol, water and a chemical reagent; the chemical reagent is one of a surfactant, a filler and an insecticidal active compound.

[0013] Furthermore, the surfactant is BEP703D.

[0014] Furthermore, the filler is acetone.

[0015] Furthermore, the insecticidal active compound is thiamethoxam, chlorfenapyr, or imidacloprid.

[0016] BEP703D is a nonionic surfactant polymerized from propylene oxide and ethylene oxide, and acts as a wetting agent in insecticides.

[0017] Furthermore, in the thrips insecticide, the mass concentration of coumestrol is 0.1 g / L~80 g / L.

[0018] The present invention also provides a method for controlling thrips pests in cowpea pods, comprising: spraying an insecticide containing coumestrol on the surface of the cowpea pods; the insecticide is prepared by mixing coumestrol with water and a chemical reagent;

[0019] The molecular formula of coumestrol is C 15 H8O 5， The chemical structure is shown in formula (1);

[0020]

[0021] Formula (1)

[0022] The chemical reagent is one of a surfactant, a filler, and an insecticidal active compound; in the insecticide, the mass concentration of coumestrol is 0.1 g / L to 80 g / L.

[0023] Furthermore, the surfactant is BEP703D; the filler is acetone; and the insecticidal active compound is thiamethoxam, chlorfenapyr, or imidacloprid.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention provides the use of coumestrol in the preparation of a thrips insecticide. The use of coumestrol in killing thrips is a new use. The present invention uses coumestrol from a plant as a main component and mixes it with a surfactant, a filler, and one of insecticidal active compounds to prepare an insecticide. The insecticide containing coumestrol is sprayed on the surface of cowpea pods to kill insects. The insecticide is simple to prepare, has a significant insecticidal effect, and is environmentally friendly.

[0026] (2) The use of coumestrol provided by the present invention in the preparation of thrips insecticides. Coumestrol is derived from plants, and the prepared insecticide has significant insecticidal effects and is environmentally friendly. Coumestrol can be obtained from commercially available products and is easily available. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the molecular formula of the plant-derived insecticidal compound coumestrol.

[0028] Figure 2 The figure is a comparative bar graph of the mortality rates of common giant thrips adults in the control group and the treatment group in Example 1.

[0029] Figure 3 The figure is a comparative bar graph of the mortality rates of common giant thrips nymphs in the control group and the treatment group in Example 2.

[0030] Figure 4 The figure is a comparative bar graph of the mortality rate of the control group and the treated group against adult flower thrips in Example 3.

[0031] Figure 5 The figure is a comparative bar graph of the mortality rate of flower thrips nymphs in the control group and the treatment group in Example 4.

[0032] Figure 6 The figure is a comparative bar graph of the mortality rate of western flower thrips adults between the control group and the treatment group in Example 5.

[0033] Figure 7 The figure is a comparative bar graph of the mortality rate of western flower thrips nymphs between the control group and the treatment group in Example 6.

[0034] Figure 8 The figure is a comparative bar graph of the mortality rates of common giant thrips adults in the control group and the treatment group in Example 7.

[0035] Fig. 9The figure is a comparative bar graph of the mortality rates of common giant thrips adults in the control group and the treatment group in Example 8.

[0036] Fig.10 The figure is a comparative bar graph of the mortality rates of common giant thrips adults in the control group and the treatment group in Example 9.

[0037] Fig.11 The figure is a comparative bar graph of the mortality rates of common giant thrips adults in the control group and the treatment group in Example 10.

[0038] Fig.12 The figure is a comparative bar graph of the mortality rates of common giant thrips adults between the control group and the treatment group in Comparative Example 1.

[0039] Fig.13 The figure is a comparative bar graph of the mortality rates of common giant thrips adults between the control group and the treatment group in Comparative Example 2.

[0040] Fig.14 This is a bar graph comparing the mortality of the third instar larvae of the bean borer between the control group and the treatment group in Comparative Example 3. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with specific embodiments. The following are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto.

[0042] Example 1

[0043] A 1 g / L coumestrol suspension (solvent: water + 1.5% acetone) was evenly sprayed on the surface of cowpea pods. After drying, 100 common giant thrips adults were inoculated. After 48 hours, the mortality rate of common giant thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are shown in the attached Figure 2 .

[0044] Example 2

[0045] Treatment group: Spray 1 g / L coumestrol suspension (solvent is water + 1.5% acetone) evenly on the surface of cowpea pods, wait for it to dry, and then inoculate 100 common thrips nymphs. After 48 hours, the mortality rate of common thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are attached. Figure 3 .

[0046] Example 3

[0047] Treatment group: Spray 1 g / L coumestrol suspension (solvent is water + 1.5% acetone) evenly on the surface of cowpea pods, wait for it to dry, and then inoculate 100 adult flower thrips. After 48 hours, the mortality rate of flower thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are attached. Figure 4 .

[0048] Example 4

[0049] Treatment group: Spray 1 g / L coumestrol suspension (solvent is water + 1.5% acetone) evenly on the surface of cowpea pods, wait for it to dry, and then inoculate 100 nymphs of flower thrips. After 48 hours, the mortality rate of flower thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are attached. Figure 5 .

[0050] Example 5

[0051] Treatment group: Spray 1 g / L coumestrol suspension (solvent is water + 1.5% acetone) evenly on the surface of cowpea pods, wait for it to dry, and then inoculate 100 western flower thrips adults. After 48 hours, the mortality rate of western flower thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are attached. Figure 6 .

[0052] Example 6

[0053] Treatment group: Spray 1 g / L coumestrol suspension (solvent is water + 1.5% acetone) evenly on the surface of cowpea pods, wait for it to dry, and then inoculate 100 western flower thrips nymphs. After 48 hours, the mortality rate of western flower thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are shown in the attached Figure 7 .

[0054] Example 7

[0055] Treatment group: Spray 1 g / L coumestrol suspension (solvent is water + 5% surfactant BEP703D) evenly on the surface of cowpea pods, wait for it to dry, and then inoculate 100 common giant thrips adults. After 48 hours, the mortality rate of common giant thrips was calculated. The control group was sprayed with 5% surfactant BEP703D aqueous solution on cowpea pods. The results are shown in the attached Figure 8 .

[0056] Example 8

[0057] Treatment group: Spray 1 g / L coumestrol suspension (solvent is 25% thiamethoxam diluted 5000 times) evenly on the surface of cowpea pods, wait for it to dry, then inoculate 100 common giant thrips adults, and calculate the mortality rate of common giant thrips after 48 hours. The control group was sprayed with 25% thiamethoxam diluted 5000 times on cowpea pods. The results are shown in the attached Fig. 9 .

[0058] Example 9

[0059] Coumestrol suspension (solvent is water + 1.5% acetone) with a concentration of 0.1 g / L was evenly sprayed on the surface of cowpea pods. After drying, 100 common giant thrips adults were inoculated. After 48 hours, the mortality rate of common giant thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are shown in the attached Fig.10 .

[0060] Example 10

[0061] Coumestrol suspension (solvent is water + 1.5% acetone) with a concentration of 80 g / L was evenly sprayed on the surface of cowpea pods. After drying, 100 common giant thrips adults were inoculated. After 48 hours, the mortality rate of common giant thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are shown in the attached Fig.11 .

[0062] Comparative Example 1

[0063] Coumestrol suspension (solvent is water + 1.5% acetone) with a concentration of 0.05 g / L was evenly sprayed on the surface of cowpea pods. After drying, 100 common giant thrips adults were inoculated. After 48 hours, the mortality rate of common giant thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are shown in the attached Fig.12 .

[0064] Comparative Example 2

[0065] A 1 g / L apigenin suspension (solvent is water + 1.5% acetone) was evenly sprayed on the surface of cowpea pods. After drying, 100 common giant thrips adults were inoculated. After 48 hours, the mortality rate of common giant thrips was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are shown in the attached Fig.13 .

[0066] Comparative Example 3

[0067] A 1 g / L coumestrol suspension (solvent: water + 1.5% acetone) was evenly sprayed on the surface of cowpea pods. After drying, 100 third-instar larvae of bean borer were inoculated. After 48 hours, the mortality rate of bean borer larvae was calculated. The control group was cowpea pods sprayed with 1.5% acetone-water solution. The results are shown in the attached figure. Fig.14 .

Claims

1. The use of coumestrol in the preparation of thrips insecticide, characterized in that: The molecular formula of coumestrol is C 15 H8O 5， The chemical structure is shown in formula (1); Formula (1).

2. The use according to claim 1, characterized in that The thrips are Macrothrips, Western Flower Thrips and / or Flower Thrips.

3. The use according to claim 1, characterized in that The thrips are adults and / or nymphs.

4. The use according to claim 1, characterized in that The thrips insecticide is prepared by mixing coumestrol, water and a chemical reagent; the chemical reagent is one of a surfactant, a filler and an insecticidal active compound.

5. The use according to claim 4, characterized in that The surfactant is BEP703D.

6. The use according to claim 4, characterized in that The filler is acetone.

7. The use according to claim 4, characterized in that The insecticidal active compound is thiamethoxam, chlorfenapyr, or imidacloprid.

8. The use according to claim 4, characterized in that In the thrips insecticide, the mass concentration of coumestrol is 0.1 g / L~80 g / L.

9. A method for controlling thrips pests in cowpea pods, characterized in that: include: Spraying an insecticide containing coumestrol on the surface of cowpea pods; the insecticide is prepared by mixing coumestrol with water and a chemical reagent; The molecular formula of coumestrol is C 15 H8O 5， The chemical structure is shown in formula (1); Formula (1) The chemical reagent is one of a surfactant, a filler, and an insecticidal active compound; in the insecticide, the mass concentration of coumestrol is 0.1 g / L to 80 g / L.

10. The method for controlling thrips pests in cowpea pods according to claim 9, characterized in that: The surfactant is BEP703D; the filler is acetone; and the insecticidal active compound is thiamethoxam, chlorfenapyr, or imidacloprid.

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