Insecticide and method for controlling plant pests

Abstract

The application relates to an insecticide and a plant pest prevention and control method, and relates to the technical field of plant insecticides. The insecticide comprises dodder extract; and the preparation method of the dodder extract comprises the following steps: first extraction treatment is performed on dry dodder powder by using a first solvent, the extraction liquid is removed, and the powder after the first extraction treatment is obtained; the first solvent is an aliphatic alkane solvent; second extraction treatment is performed on the powder after the first extraction treatment by using a second solvent, the extraction liquid is removed, and the powder after the second extraction treatment is obtained; the second solvent is an ester organic solvent; third extraction treatment is performed on the powder after the second extraction treatment by using a third solvent, and the third solvent extraction liquid is collected; the third solvent is one or more of ethanol, methanol and water; and solvent removal treatment is performed on the third solvent extraction liquid, so that the dodder extract is obtained. The application mainly develops a green, efficient, low-toxicity and non-drug-resistant insecticide.

Description

Technical Field

[0001] This invention relates to the field of plant insecticide technology, and in particular to an insecticide and a method for controlling plant pests. Background Technology

[0002] As a major agricultural country, my country faces the challenge of increasing grain production to ensure agricultural security given its limited arable land. Pests are a key factor affecting crop yield and quality in agricultural production. Globally, pests cause over 20% of crop losses annually.

[0003] Currently, effective pest control still relies heavily on the use of chemical pesticides. While this method effectively controls pests, it also leads to numerous problems, including environmental pollution, increased pest resistance, and pesticide residues that harm human health. Meanwhile, biopesticides account for less than 10% of the market. Therefore, the development of green pest control technologies is urgently needed. Natural plant extracts, with their advantages of low toxicity, easy degradation, and low likelihood of inducing pesticide resistance, have become an important direction for the development of new biopesticides.

[0004] In summary, there is an urgent need to develop a green, efficient, low-toxicity plant-based insecticide that is not prone to developing resistance. Summary of the Invention

[0005] In view of this, the present invention provides an insecticide and a method for controlling plant pests, the main purpose of which is to develop a green, efficient, low-toxic plant insecticide that is not prone to developing resistance.

[0006] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0007] On one hand, embodiments of the present invention provide an insecticide, wherein the insecticide includes dodder seed extract; wherein the preparation method of the dodder seed extract includes the following steps:

[0008] First extraction step: The dried dodder powder is subjected to a first extraction treatment using a first solvent, and then the first solvent extract is removed to obtain the powder after the first extraction treatment; wherein, the first solvent is an aliphatic alkane solvent;

[0009] Second extraction process: The powder after the first extraction process is subjected to a second extraction process using a second solvent, and then the second solvent extract is removed to obtain the powder after the second extraction process; wherein, the second solvent is an ester-based organic solvent;

[0010] The third extraction process involves using a third solvent to perform a third extraction on the powder after the second extraction process, and collecting the third solvent extract; wherein the third solvent is one or more of ethanol, methanol, and water.

[0011] Solvent removal treatment step: The third solvent extract is subjected to solvent removal treatment to obtain Cuscuta chinensis extract.

[0012] Preferably, the aliphatic alkane solvent includes one or more of n-hexane, petroleum ether, and pentane.

[0013] Preferably, the ester organic solvent is ethyl acetate and / or methyl acetate.

[0014] Preferably, prior to the first extraction step, the method further includes:

[0015] Steps for preparing dried dodder powder: Grind dodder seeds into powder and dry them to obtain dried dodder powder.

[0016] Preferably, the first extraction step includes: mixing the first solvent and dodder powder in a container, performing a first ultrasonic extraction treatment for half an hour to one hour, and then discarding the first solvent extract; wherein, the first ultrasonic extraction treatment is repeated 3 to 5 times; wherein, during the first ultrasonic extraction treatment, the mass ratio of the first solvent to the powder is 1:1 to 1:1.5.

[0017] Preferably, the second extraction step includes: mixing the second solvent and the powder after the first extraction treatment in a container, performing a second ultrasonic extraction treatment for half an hour to one hour, and then discarding the second solvent extract; wherein, the second ultrasonic extraction treatment is repeated 3 to 5 times; wherein, during the second ultrasonic extraction treatment, the mass ratio of the second solvent to the powder is 1:1 to 1:1.5.

[0018] Preferably, the third extraction step includes: mixing the third solvent and the powder after the second extraction in a container, performing a third ultrasonic extraction for half an hour to one hour, and collecting the third solvent extract; wherein, the third extraction is repeated 3 to 5 times, and all the third solvent extracts are collected; wherein, in the ultrasonic extraction, the mass ratio of the third solvent to the powder is 1:1 to 1:1.5.

[0019] Preferably, the dodder seed extract comprises: flavonoids, glycosides, lignans, triterpenoids, alkaloids, and polysaccharides; wherein,

[0020] The flavonoids include quercetin, kaempferol, and isorhamnetin;

[0021] The glycosides include quercetin-3-O-glucoside and kaempferol-3-O-rutin glycoside;

[0022] The lignans include pinoresinin and eugenolin;

[0023] The triterpenoids include oleanolic acid and ursolic acid;

[0024] The alkaloids include dodderine.

[0025] Preferably, the insecticide is a plant pest insecticide.

[0026] Preferably, the plant pest control agent is an agricultural crop pest control agent.

[0027] Preferably, the plant pests include beet armyworm larvae, fall armyworm, cotton bollworm, and armyworm.

[0028] Preferably, the insecticide is an insect feeding inhibitor.

[0029] Preferably, the insecticide is used to promote the increase of plant hormones JA and SA content, as well as to promote the increase of insect-resistant secondary metabolite TPI content in plants.

[0030] Preferably, the insecticide comprises dodder extract and water; wherein the concentration of the dodder extract in the insecticide is 10-20 wt%.

[0031] Preferably, the insecticide comprises a formulation and a surfactant; wherein the formulation comprises dodder extract and water; wherein the concentration of the dodder extract in the formulation is 10-20 wt%; and the mass ratio of the formulation to the surfactant is 1:1000 to 1:2000.

[0032] Preferably, the surfactant is a silwet surfactant or a nonionic surfactant.

[0033] On the other hand, embodiments of the present invention provide a method for controlling plant pests, wherein the insecticide described in any of the above claims is sprayed on the plant to control pests.

[0034] Preferably, the plant includes crops.

[0035] Compared with the prior art, the insecticide and method for controlling plant pests of the present invention have at least the following beneficial effects:

[0036] On one hand, embodiments of the present invention provide an insecticide; wherein the insecticide includes dodder extract; wherein the preparation method of the dodder extract includes the following steps: performing a first extraction treatment on dried dodder powder using a first solvent, and then removing the first solvent extract to obtain powder after the first extraction treatment; wherein the first solvent is an aliphatic alkane solvent; performing a second extraction treatment on the powder after the first extraction treatment using a second solvent, and then removing the second solvent extract to obtain powder after the second extraction treatment; wherein the second solvent is an ester organic solvent; performing a third extraction treatment on the powder after the second extraction treatment using a third solvent, and collecting the third solvent extract; wherein the third solvent is one or more of ethanol, methanol, and water; and removing the solvent from the third solvent extract to obtain the dodder extract. The preparation method described above yields a dodder extract comprising: flavonoids, glycosides, lignans, triterpenoids, alkaloids, and polysaccharides. The flavonoids include quercetin, kaempferol, and isorhamnetin; the glycosides include quercetin-3-O-glucoside and kaempferol-3-O-rutin glycoside; the lignans include pinoresinin and eugenol; the triterpenoids include oleanolic acid and ursolic acid; and the alkaloids include dodderine. It should be noted that the dodder extract obtained using the above method possesses a dual insecticidal mechanism: first, a direct toxic effect, acting as an inhibitor of insect feeding, suppressing insect feeding, growth, and reproduction, leading to direct insect death with a mortality rate exceeding 42%. Secondly, it has an indirect defensive effect. The dodder extract acts as a promoter of plant hormones JA and SA, inducing plants to produce more JA and SA, initiating systemic resistance, and promoting the increase of the content of insect-resistant active substance TPI in plants, thereby inhibiting the feeding, growth, and reproduction of pests. In summary, this invention is the first to discover that the crude extract of dodder extracted using a specific method has significant and excellent insecticidal activity and can be used as an insecticide, with an inhibition rate of over 50% against pests. It also has a repellent effect on pests, with an efficacy of over 76%. Furthermore, the crude extract of dodder is a natural product of plant origin, causing no environmental pollution and not affecting the normal growth of plants.

[0037] It should be noted that: (1) the insecticide may consist only of dodder extract. Here, the dodder extract is in powder form, can be stored for a long time, and can be directly mixed with water for use in insect control. (2) the insecticide may consist only of dodder extract and water; wherein the concentration of dodder extract in the insecticide is 10-20 wt%. (3) another type of insecticide may include a formulation and a surfactant; wherein the formulation includes dodder extract and water; wherein the concentration of dodder extract in the formulation is 10-20 wt%; the mass ratio of the formulation to the surfactant is 1:1000. In this insecticide, a surfactant is added in addition to dodder extract and water, which can improve the adhesion of the dodder extract insecticide to plant leaves, thereby improving the insect control effect.

[0038] In summary, this invention provides an insecticide and a method for controlling plant pests. Through a predetermined extraction method, a crude extract of Cuscuta chinensis containing specific components is obtained, resulting in a significantly superior insecticidal activity. This allows for the preparation of insecticides suitable for different plants (crops), inhibiting pest feeding, growth, and reproduction, enhancing the plant's own insect resistance, thereby reducing the use of chemical pesticides, minimizing potential harm to the ecological environment and human health, providing an operable technical solution for the green and sustainable development of agriculture, and opening up new directions for the research and development of natural plant-derived insecticides.

[0039] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0040] Figure 1 This is a comparison of the changes in plant hormone content in the leaves of induced tomato plants in the treatment and control groups in Example 5.

[0041] Figure 2 This is a comparison of the changes in plant hormone content in the leaves of induced tomato plants in the treatment and control groups in Example 6.

[0042] Figure 3 The changes in plant hormone content in tomato leaves induced in the treatment and control groups in Example 4;

[0043] Figure 4 The biological weight of Spodoptera litura larvae in the statistical treatment group and the control group in Example 5;

[0044] Figure 5 The curves showing the changes in the activity of insect-resistant proteins (i.e., trypsin inhibitors (TPI)) in tomato leaves of the treated and control groups in Example 6 are shown.

[0045] Figure 6This is a graph showing the experimental results from Example 7, where... Figure 6 Figure A in the figure is a statistical graph showing the changes in bioweight of Spodoptera litura larvae in the treatment group and the control group; Figure 6 Image B in the image shows photos of tobacco leaves in the treatment and control groups two days after the beet armyworms fed on tobacco leaves. Figure 6 Image C in the image shows the size of the insects in the treatment and control groups 8 days after the beet armyworms fed on three-star tobacco.

[0046] Figure 7 This is a graph showing the experimental results from Example 8; where, Figure 7 Figure A in the figure is a statistical graph showing the changes in bioweight of Spodoptera litura larvae in the treatment group and the control group; Figure 7 Image B in the image shows the body size of the insects in the treatment and control groups 6 days after the beet armyworms fed on Arabidopsis thaliana.

[0047] Figure 8 This is a graph showing the experimental results from Example 9; where, Figure 8 Figure A in the figure shows selective experimental photographs of leaves in the treatment and control groups 3 hours after the beet armyworms fed on them. Figure 8 Image B in the image shows photographs of Arabidopsis leaves in the treatment and control groups 6 hours after the beet armyworms fed on them. Figure 8 Figure C in the figure shows the number of Arabidopsis thaliana leaves remaining on the leaves of the treatment group and the control group 3 hours and 6 hours after the beet armyworms fed on them. Detailed Implementation

[0048] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0049] Dodder (Cuscuta chinensis) is a holoparasitic plant belonging to the genus Cuscuta in the Convolvulaceae family. As a traditional Chinese medicine, its extracts contain various active ingredients such as flavonoids and polysaccharides, demonstrating anti-inflammatory and antioxidant effects in the medical field. Existing technologies have investigated the medicinal value of dodder extracts. The inventors of this invention have discovered for the first time that the activity of dodder extracts obtained using different extraction methods varies significantly. Furthermore, dodder extracts containing specific components obtained using specific extraction methods exhibit significant insect-resistant activity, which is of great significance for developing green and environmentally friendly plant protection agents and promoting sustainable agricultural development.

[0050] This invention aims to overcome the challenges of chemical pesticide dependence, environmental pollution, and pest resistance in current agricultural production. It focuses on a green, efficient, low-toxicity plant-based insect-resistant technology that utilizes a specific extract of dodder seed obtained through a particular extraction method. By extracting the natural active ingredients from dodder seed, insect-resistant formulations suitable for various crops can be prepared to inhibit pest feeding, growth, and reproduction, thereby enhancing the plant's own insect resistance. This reduces the use of chemical pesticides, minimizes potential harm to the ecological environment and human health, provides a workable technical solution for green and sustainable agricultural development, and opens up new directions for the research and development of natural plant-derived insecticides.

[0051] The main solution of the present invention is as follows:

[0052] On one hand, embodiments of the present invention provide an insecticide, wherein the insecticide includes dodder seed extract; wherein the preparation method of the dodder seed extract includes the following steps:

[0053] Steps for preparing dried dodder powder: Collect fresh southern dodder growing on the host plant, grind it into powder in a liquid nitrogen environment, put it into a freeze dryer, and freeze dry for 24-48 hours to obtain dried dodder powder.

[0054] First extraction step: Weigh the freeze-dried dodder seeds of a set mass, transfer them into a clean glass beaker, and add equal mass ratios of n-hexane, petroleum ether, pentane, etc. as the first solvent. Cover with plastic wrap and ultrasonically extract for half an hour. Pour the first solvent extract into a waste liquid tank. Repeat this step 3 times to obtain the powder after the first extraction treatment.

[0055] Second extraction process: Then, add ethyl acetate, methyl acetate and other second solvents in equal mass ratios to the powder after the first extraction process. After ultrasonic extraction for half an hour, pour the extract of the second solvent into the waste liquid tank. Repeat this step 3 times until the pigment is completely extracted and the solution gradually turns light green, thus obtaining the powder after the second extraction process.

[0056] Third extraction step: Subsequently, add an equal mass ratio of ethanol, methanol, or water (or other third solvent) to the powder after the second extraction, cover with plastic wrap, and ultrasonically extract for half an hour. Collect the ethanol-extracted third solvent extract, and repeat this step three times. Collect all of the third solvent extract.

[0057] Solvent removal treatment step: The third solvent extract is subjected to solvent removal treatment to obtain Cuscuta chinensis extract. Specifically, the three-solvent extract is placed in a round-bottom flask and the solvent is evaporated using a rotary evaporator for more than 24 hours until all the solvent is evaporated and a dark brown solid appears at the bottom of the flask, thus obtaining Cuscuta chinensis extract.

[0058] The dodder seed extract includes: flavonoids, glycosides, lignans, triterpenoids, alkaloids, and polysaccharides; wherein the flavonoids include quercetin, kaempferol, and isorhamnetin; and the glycosides include quercetin-3-O-glucoside and kaempferol-3-O-rutin glycoside.

[0059] The lignans include pinoresinin and eugenol; the triterpenoids include oleanolic acid and ursolic acid; and the alkaloids include dodderine.

[0060] The insecticide is a plant pest insecticide. Preferably, the plant pests include beet armyworm larvae, fall armyworm, cotton bollworm, armyworm, etc.

[0061] It should be noted that: (1) This invention is the first to discover that a dodder extract containing a specific component prepared using a specific extraction method has insecticidal activity, with an inhibition rate of over 50% against beet armyworm larvae, and also has an insect repellent effect of over 76%. (2) The dodder extract containing a specific component prepared using the above-mentioned specific extraction method has a dual mechanism of action: First, direct toxicity, the extract can cause direct death of beet armyworms, with a mortality rate of over 42%. Second, indirect defense, the crude extract can induce plants to produce more jasmonic acid (JA), initiating systemic resistance. (3) This invention is an environmentally friendly formulation technology. The crude extract of dodder is a natural product of plant origin, which does not pollute the environment and does not affect the normal growth of plants.

[0062] If the insecticide consists only of dodder extract, the dodder extract can be stored for a long time as an insecticide. When using it, simply mix it with water and spray it onto the plants.

[0063] If the insecticide comprises dodder extract and water; wherein the concentration of the dodder extract in the insecticide is 10-20 wt%.

[0064] If the insecticide comprises a formulation and a surfactant; wherein the formulation comprises dodder extract and water; wherein the concentration of the dodder extract in the formulation is 10-20 wt%; the mass ratio of the formulation to the surfactant is 1:1000 to 1:2000; preferably, the surfactant is a silwet surfactant or a nonionic surfactant; more preferably, the nonionic surfactant is Tween 20 surfactant.

[0065] In summary, the insecticide and plant pest control method proposed in this embodiment of the invention have the following benefits:

[0066] 1. Environmental benefits: Reduces the use of chemical pesticides.

[0067] 2. Ecological benefits: High safety for insect natural enemies.

[0068] 3. Economic benefits: It can effectively reduce pest infestation and induce endogenous resistance in plants.

[0069] The present invention will be further illustrated below with specific embodiments:

[0070] Example 1

[0071] This embodiment prepares a dodder seed extract, mainly including the following steps:

[0072] Fresh dodder seeds growing on host plants were collected, ground into powder under liquid nitrogen, and then freeze-dried in a freeze dryer for 24 hours to obtain dried dodder seed powder.

[0073] Weigh the freeze-dried dodder seeds and transfer them to a clean glass beaker. Add an equal mass ratio of n-hexane solvent and cover with plastic wrap. After ultrasonic extraction for half an hour, pour the n-hexane solvent into a waste container. Repeat this step three times. Then add an equal mass ratio of ethyl acetate solvent and ultrasonically extract for half an hour. Pour the ethyl acetate into a waste container and repeat this step three times until the pigment is completely extracted and the solution gradually turns light green. Next, add an equal mass ratio of ethanol solvent, cover with plastic wrap, and ultrasonically extract for half an hour. Collect the ethanol extract and repeat this step three times. Collect all the ethanol extract and place it in a round-bottom flask. Use a rotary evaporator to evaporate the solvent for more than 24 hours until all the solvent has evaporated and a dark brown solid appears at the bottom of the flask, thus obtaining the dodder seed extract (ethanol solvent dodder seed extract).

[0074] The dodder extract obtained in this embodiment includes: flavonoids, glycosides, lignans, triterpenoids, alkaloids, and polysaccharides; among which, flavonoids include quercetin, kaempferol, isorhamnetin, etc.; glycosides include quercetin-3-O-glucoside, kaempferol-3-O-rutin glycoside, etc.; lignans include pinoresinin, eugenol, etc.; triterpenoids include oleanolic acid, ursolic acid, etc.; and alkaloids include dodderine.

[0075] Example 2

[0076] This embodiment prepares the dodder extract from Example 1 into a ready-to-use insecticide. Specifically, the dodder extract and water are mixed to form the insecticide; wherein the concentration of the dodder extract in the insecticide is 10 wt%.

[0077] Example 3

[0078] This embodiment prepares the dodder extract from Example 1 into a directly usable insect repellent. Specifically, the dodder extract and water are formulated into a preparation; wherein the concentration of the dodder extract in the preparation is 20 wt%. This preparation is mixed with silwet surfactant at a mass ratio of 1:1000 to obtain the insect repellent.

[0079] It should be noted that the activity of insecticides is not related to surfactants; surfactants simply enable insecticides to adhere better to plant leaves.

[0080] Comparative Example 1

[0081] Comparative Example 1 describes the preparation of a dodder seed extract, which mainly includes the following steps:

[0082] Fresh dodder seeds growing on host plants were collected, ground into powder under liquid nitrogen, and then freeze-dried in a freeze dryer for 24 hours to obtain dried dodder seed powder.

[0083] Weigh the freeze-dried dodder seeds and transfer them to a clean glass beaker. Add an equal mass ratio of n-hexane solvent and cover with plastic wrap. After ultrasonic extraction (with constant stirring) for half an hour, collect the n-hexane extract. Repeat this step 3 times to collect all the n-hexane extract. Place the extract in a round-bottom flask and evaporate the solvent using a rotary evaporator for more than 24 hours until all the solvent has evaporated and a brownish-yellow oily / paste-like substance appears at the bottom of the flask. This yields the n-hexane solvent-treated dodder seed extract.

[0084] Here, the dodder extract (n-hexane solvent dodder extract) obtained in Comparative Example 1 includes: mainly fat-soluble nonpolar components, primarily fatty acid glycerides, phytosterols, fat-soluble terpenes (monoterpenes / sesquiterpenes), volatile oils, and fat-soluble pigments.

[0085] Comparative Example 2

[0086] Comparative Example 2 prepared a dodder seed extract, mainly including the following steps:

[0087] Fresh dodder seeds growing on host plants were collected, ground into powder under liquid nitrogen, and then freeze-dried in a freeze dryer for 24 hours to obtain dried dodder seed powder.

[0088] Weigh the freeze-dried dodder seeds and transfer them to a clean glass beaker. Add an equal mass ratio of ethyl acetate solvent and cover with plastic wrap. After ultrasonic extraction (with constant stirring) for half an hour, collect the ethyl acetate extract. Repeat this step 3 times to collect all the ethyl acetate extract. Place the extract in a round-bottom flask and evaporate the solvent using a rotary evaporator for more than 24 hours until all the solvent has evaporated and a pale yellow / yellowish-brown powder appears at the bottom of the flask, thus obtaining the dodder seed extract.

[0089] Here, the dodder extract (ethyl acetate solvent dodder extract) obtained in Comparative Example 2 includes: free flavonoids (free flavonoids such as dodderin, quercetin, and kaempferol), lignans; it also contains trace amounts of phenolic acids, sterol aglycones, and trace amounts of fat-soluble sterols.

[0090] Comparative Example 3

[0091] Comparative Example 3: The dodder extract prepared in Comparative Example 1 was used to prepare a ready-to-use insecticide. Specifically, the dodder extract and water were formulated into a preparation; wherein the concentration of the dodder extract in the preparation was 20 wt%. This preparation was mixed with silwet surfactant at a mass ratio of 1:1000 to obtain the insecticide.

[0092] Comparative Example 4

[0093] Comparative Example 4: The dodder extract prepared in Comparative Example 2 was used to prepare a ready-to-use insecticide. Specifically, the dodder extract and water were formulated into a preparation; wherein the concentration of the dodder extract in the preparation was 20 wt%. This preparation was mixed with Silwet surfactant at a mass ratio of 1:1000 to obtain the insecticide.

[0094] Comparative Example 5

[0095] Comparative Example 5 involved spraying the insecticide from Comparative Example 3 onto the leaves of cultivated tomatoes (200-300 µL of insecticide per plant), serving as the treatment group. A control group was also included, where water was sprayed onto the leaves of the cultivated tomatoes. Two days after spraying, the leaves of the beet armyworm were allowed to feed on the leaves for 2, 4, and 6 days.

[0096] from Figure 1 It can be seen that the tomatoes sprayed with the insecticide in Comparative Example 3 had no significant effect on the growth of beet armyworm larvae. This indicates that the use of hexane as a solvent cannot extract insect-resistant active substances (such as dodder alkaloids, polysaccharides, etc.) from dodder, or the extracted insect-resistant active substances are too few (undetectable), and therefore cannot exert the corresponding insect-resistant effect.

[0097] Comparative Example 6

[0098] Comparative Example 6 involved spraying the insecticide from Comparative Example 4 onto the leaves of cultivated tomatoes (200-300 µL of insecticide per plant), serving as the treatment group. A control group was also included, where water was sprayed onto the leaves of the cultivated tomatoes. Two days after spraying, the leaves of the beet armyworm were allowed to feed on the leaves for 2, 4, and 6 days.

[0099] from Figure 2It can be seen that the tomatoes sprayed with the insecticide in Comparative Example 4 had no significant effect on the growth of beet armyworm larvae. This indicates that ethyl acetate solvent cannot extract insecticidal active substances (such as dodder alkaloids, polysaccharides, etc.) from dodder, or the extracted insecticidal active substances are too few (undetectable), and therefore cannot exert the corresponding insecticidal effect.

[0100] Example 4

[0101] In this embodiment, the insecticide prepared in Example 3 was sprayed onto the leaves of cultivated tomatoes (200-300 µL of insecticide per plant) as the treatment group. A control group was also included, in which water was sprayed onto the leaves of the cultivated tomatoes.

[0102] The changes in the content of hormones (jasmonic acid JA, jasmonic acid-isoleucine JA-lle, salicylic acid SA, indoleacetic acid IAA, and abscisic acid ABA) in cultivated tomato leaves were detected 1 hour and 12 hours after spraying.

[0103] in, Figure 3 The changes in plant hormone content in tomato plant leaves were induced in the treatment and control groups of Example 4. Specifically, in... Figure 3 In the figure, the data are mean ± SE; n = 4-5; ns = not significant; **, P < 0.01, ***, P < 0.001.

[0104] from Figure 3 It can be seen that the insecticide prepared from dodder extract can induce a significant increase in the content of plant hormones JA, JA-Ile and SA involved in the defense response in tomato plants.

[0105] Example 5

[0106] In this embodiment, the insecticide prepared in Example 3 was sprayed exogenously onto cultivated tomatoes (200-300 µL of insecticide per plant) as the treatment group. A control group was also included, in which water was sprayed exogenously onto the cultivated tomatoes. Two days after spraying, the beet armyworm larvae were allowed to feed on the leaves of the cultivated tomatoes for 2, 4, and 6 days.

[0107] The biomass of Spodoptera litura larvae in the treatment and control groups is shown in [reference]. Figure 4 As shown; where, Figure 4 The data are mean ± SE, n=60; ns=not significant, *, P < 0.05.

[0108] from Figure 4 It can be seen that tomatoes sprayed with the insecticide prepared in Example 3 can significantly inhibit the growth of beet armyworm larvae.

[0109] Example 6

[0110] In this embodiment, the insecticide prepared in Example 3 was exogenously sprayed onto cultivated tomatoes (200-300 µL of insecticide per plant), serving as the treatment group. A control group was also included, in which water was sprayed onto the cultivated tomatoes. Two days after spraying, changes in the activity of insect-resistant proteins (i.e., trypsin inhibitors (TPIs)) in the tomato leaves of both the treatment and control groups were detected. See [link to relevant documentation]. Figure 5 As shown. In Figure 5 In the figure, the data are the mean ± SE; n = 5 in the figure; **, P < 0.01.

[0111] from Figure 5 It can be seen that spraying the insecticide prepared in Example 3 can induce a significant increase in the content of insect-resistant secondary metabolite TPI (trypsin inhibitor) in tomatoes.

[0112] Example 7

[0113] In this embodiment, the insecticide prepared in Example 3 was applied exogenously to Sanxing tobacco (200-300 µL of insecticide per plant) as the treatment group. A control group was also included, in which water was applied exogenously to the Sanxing tobacco. After 48 hours of treatment, both the treatment and control groups were allowed to feed on the cultivated tobacco leaves for 2, 5, and 8 days, respectively.

[0114] For the changes in bioweight of Spodoptera litura larvae in the treatment and control groups, see [reference needed]. Figure 6 As shown in Figure A (data is mean ± SE; in Figure 4 In Figure A, n = 50, and in Figure C, n = 11-12; **, P < 0.01, ***, P < 0.001).

[0115] Two days after the beet armyworm fed on tobacco leaves, photographs of the ingested tobacco in the treatment and control groups are shown below. Figure 6 As shown in Figure B.

[0116] Photographs showing the body size of the beet armyworms in the treatment and control groups 8 days after they fed on tobacco. (See attached image) Figure 6 As shown in Figure C.

[0117] from Figure 6 It can be seen that spraying the insecticide prepared from the ethanol solvent Cuscuta extract (i.e., the insecticide prepared in Example 3) can significantly improve the insect resistance of tobacco.

[0118] Example 8

[0119] In this embodiment, the insecticide prepared in Example 3 was sprayed exogenously onto Arabidopsis thaliana (150-200 µL of insecticide per plant) as the treatment group. A control group was also added, in which water was sprayed exogenously onto Arabidopsis thaliana. Two days after treatment, the larvae of the beet armyworm were allowed to feed on the leaves of the cultivated Arabidopsis thaliana for 2, 4, and 6 days.

[0120] The changes in bioweight of Spodoptera litura larvae in the treatment and control groups are shown in [reference needed]. Figure 7 As shown in Figure A (in Figure A, the data are mean ± SE, n=50, *, P < 0.05, **, P < 0.01).

[0121] Photographs showing the body size of the insects in the treatment and control groups 6 days after the beet armyworm fed on Arabidopsis thaliana. (See attached image) Figure 7 As shown in Figure B (where n = 10).

[0122] from Figure 7 It can be seen that spraying the insecticide prepared from the ethanol solvent Cuscuta extract (i.e., the insecticide prepared in Example 3) can significantly improve the insect resistance of Arabidopsis thaliana.

[0123] Example 9

[0124] In this embodiment, the insecticide prepared in Example 3 was sprayed exogenously onto the leaves of Arabidopsis thaliana (150-200 µL of insecticide per plant) as the treatment group; a control group was also added, in which water was sprayed exogenously onto the leaves of Arabidopsis thaliana. The leaves of the treatment group and the control group were removed and the petioles were wrapped with absorbent paper to keep them moist. The leaves of the control group and the treatment group were placed alternately, and then the larvae of the beet armyworm were allowed to feed on the leaves.

[0125] The photo of the beet armyworm three hours after feeding can be found here. Figure 8 Figure A in the image. See also the photo of the beet armyworm 16 hours after feeding. Figure 8 Figure B in the figure shows the number of Spodoptera litura moths remaining on Arabidopsis leaves 3 and 16 hours after feeding. (See Figure B for details.) Figure 8 Figure C in the diagram.

[0126] from Figure 8 It can be seen that the insect repellent prepared from the ethanol solvent Cuscuta extract (i.e., the insect repellent prepared in Example 3) has a repellent effect on Spodoptera litura.

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An insecticide, characterized in that, The insecticide includes dodder seed extract; wherein, the preparation method of the dodder seed extract includes the following steps: First extraction process: The dried dodder powder is subjected to a first extraction process using a first solvent, and then the first solvent extract is removed to obtain the powder after the first extraction process; wherein, the first solvent is an aliphatic alkane solvent; The second extraction process involves using a second solvent to perform a second extraction process on the powder after the first extraction process, and then removing the second solvent extract to obtain the powder after the second extraction process; wherein, the second solvent is an ester-based organic solvent. The third extraction process involves using a third solvent to perform a third extraction on the powder after the second extraction process, and collecting the third solvent extract; wherein the third solvent is one or more of ethanol, methanol, and water. Solvent removal treatment step: The third solvent extract is subjected to solvent removal treatment to obtain Cuscuta chinensis extract.

2. The insecticide according to claim 1, characterized in that, The aliphatic alkane solvents include one or more of n-hexane, petroleum ether, and pentane.

3. The insecticide according to claim 1, characterized in that, The ester organic solvent is ethyl acetate and / or methyl acetate.

4. The insecticide according to claim 1, characterized in that, Prior to the first extraction step, the process further includes: Steps for preparing dried dodder powder: Grind dodder seeds into powder and dry them to obtain dried dodder powder.

5. The insecticide according to claim 1, characterized in that, The first extraction process includes: mixing the first solvent and dodder powder in a container, performing a first ultrasonic extraction process for half an hour to one hour, and then discarding the first solvent extract; wherein the first ultrasonic extraction process is repeated 3 to 5 times; wherein, during the first ultrasonic extraction process, the mass ratio of the first solvent to the powder is 1:1 to 1:1.

5.

6. The insecticide according to claim 1, characterized in that, The second extraction process includes: mixing the second solvent and the powder after the first extraction process in a container, performing a second ultrasonic extraction process for half an hour to one hour, and then discarding the second solvent extract; wherein the second ultrasonic extraction process is repeated 3 to 5 times; wherein, during the second ultrasonic extraction process, the mass ratio of the second solvent to the powder is 1:1 to 1:1.

5.

7. The insecticide according to claim 1, characterized in that, The third extraction process includes: mixing the third solvent and the powder after the second extraction process in a container, performing a third ultrasonic extraction process for half an hour to one hour, and collecting the third solvent extract; wherein, the third extraction process is repeated 3 to 5 times, and all the third solvent extracts are collected; wherein, in the third ultrasonic extraction process, the mass ratio of the third solvent to the powder is 1:1 to 1:1.

5.

8. The insecticide according to claim 1, characterized in that, The dodder seed extract includes: flavonoids, glycosides, lignans, triterpenoids, alkaloids, and polysaccharides; among which, The flavonoids include quercetin, kaempferol, and isorhamnetin; The glycosides include quercetin-3-O-glucoside and kaempferol-3-O-rutin glycoside; The lignans include pinoresinin and eugenolin; The triterpenoids include oleanolic acid and ursolic acid; The alkaloids include dodderine.

9. The insecticide according to claim 1, characterized in that, The insecticide is a plant pest insecticide.

10. The insecticide according to claim 9, characterized in that, The plant pest control agent is an insect control agent for crop pests.

11. The insecticide according to claim 9, characterized in that, The plant pests include beet armyworm larvae, fall armyworm, cotton bollworm, and armyworm.

12. The insecticide according to claim 1, characterized in that, The insecticide is an inhibitor of insect feeding.

13. The insecticide according to claim 1, characterized in that, The insecticide is used to promote the increase of plant hormones JA and SA, as well as to promote the increase of the content of insect-resistant secondary metabolite TPI in plants.

14. The insecticide according to claim 1, characterized in that, The insecticide comprises dodder extract and water; wherein the concentration of the dodder extract in the insecticide is 10-20 wt%.

15. The insecticide according to claim 1, characterized in that, The insecticide comprises a formulation and a surfactant; wherein the formulation comprises dodder extract and water; wherein the concentration of the dodder extract in the formulation is 10-20 wt%; and the mass ratio of the formulation to the surfactant is 1:1000 to 1:2000.

16. The insecticide according to claim 15, characterized in that, The surfactant is a nonionic surfactant.

17. A method for controlling plant pests, characterized in that, The insecticide according to any one of claims 1-15 is sprayed on plants for the control of pests.

18. The method for controlling plant pests according to claim 17, characterized in that, The plants mentioned include crops.

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