A compound agent for preventing and controlling root-knot nematodes and a preparation method thereof

Abstract

The present invention relates to the technical field of agricultural control, and specifically discloses a composite agent for controlling root-knot nematodes. The composite agent comprises a slow-release pesticide component and an inducer attached to its surface. The present invention uses the inducer to induce the expression of relevant disease-resistant genes of diseased plants, so as to achieve the purpose of improving the disease resistance of plants, and then uses the slow-release pesticide component to control the release of pesticides to treat the diseased plants. The composite agent for controlling root-knot nematodes provided by the present invention can not only control root-knot nematodes for a long time, has excellent control effect, does not need to be applied multiple times, is not easily affected by climate, but also can promote plant growth and disease resistance. The present invention effectively solves the problems in the prior art that chemical control of root-knot nematodes is prone to pollution and nematode drug resistance, and biological control of root-knot nematodes has slow effect, limited action range and is easily affected by climate.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural control, and specifically discloses a composite agent for controlling root-knot nematodes and a preparation method thereof. Background Art

[0002] Root-knot nematodes belong to the phylum Nematoda, with the subclass Secernentea, the order Tylenchida, the suborder Tylenchina, the superfamily Tylenchoidea, the family Heteroderidae, and the subfamily Meloidogyninae. Root-knot nematode diseases are one of the important factors restricting agricultural production. After being infected, the roots of the plants have obvious galls. This disease is the most common and destructive in the growth of agricultural plants. There are many types of root-knot nematodes. Currently, more than 80 species of root-knot nematodes have been reported, which can infect a variety of monocotyledonous plants, dicotyledonous plants and herbaceous plant species. With the rapid development of the agricultural planting field, the incidence rate of root-knot nematode diseases has been increasing year by year, and even in some areas, there is a situation of complete crop failure. Based on this, controlling root-knot nematode diseases of agricultural plants has become one of the main goals in the agricultural planting field.

[0003] Currently, the most commonly used control method is still chemical control. Chemical insecticidal agents such as fosthiazate and thiamethoxam are applied in the field. However, chemical agents need to be reapplied after a period of time. Long-term use will not only affect the soil environment but also cause root-knot nematodes to develop drug resistance, and the control effect will become worse and worse. Although biological control is environmentally friendly and pollution-free, biological control has a slow effect, a limited scope of action, and is easily affected by the climate. Therefore, it is of great significance for the agricultural planting field to develop an environmentally friendly, fast-acting, widely applicable method or agent with long-term effective control of root-knot nematodes. Summary of the Invention

[0004] Aiming at the problems in the prior art that chemical control of root-knot nematodes is prone to pollution and nematode drug resistance, and biological control of root-knot nematodes has a slow effect, a limited scope of action, and is easily affected by the climate. The present invention provides a composite agent for controlling root-knot nematodes and a preparation method thereof. The composite agent for controlling root-knot nematodes provided by the present invention includes an inducer and a slow-release pesticide component. The inducer induces the expression of relevant disease-resistant genes in the plant, enhances the disease resistance of the plant, changes the permeability of the plant cell membrane, facilitates the entry of the pesticide component, and achieves the purpose of efficiently controlling root-knot nematodes. The slow-release pesticide component can avoid repeated application of the agent and achieve the purpose of long-term control of root-knot nematodes. Moreover, the composite agent provided by the present invention is not affected by the climate and has a wide range of actions. The composite agent for controlling root-knot nematodes provided by the present invention has excellent control effects, does not require multiple applications, saves labor, is not affected by the climate, has a wide range of actions, and has simple and environmentally friendly raw materials and does not cause pollution.

[0005] To achieve the above invention purpose, the present invention provides the following technical solutions.

[0006] In the first aspect of the present invention, a composite agent for preventing and controlling root-knot nematodes is provided. The composite agent includes a slow-release pesticide component and an inducer attached to its surface;

[0007] Among them, the inducer includes the following raw material components: sodium selenite, vitamin C, amino acid chelate, and polyvinyl alcohol;

[0008] The slow-release pesticide component includes a pesticide component, a porous carrier, and a water-soluble slow-release film; the pesticide component includes the following raw material components: thymus extract, dracocephalum moldavica extract, ivermectin, ammonium salt, and synergist.

[0009] Compared with the prior art, the composite agent for preventing and controlling root-knot nematodes provided by the present invention includes two main components: an inducer and a slow-release pesticide component. Among them, the present invention uses the inducer to induce the expression of relevant disease-resistant genes in diseased plants to achieve the purpose of improving the disease resistance of plants. At the same time, the cell membrane permeability of the diseased plants treated with the inducer increases, making it easier for the subsequent pesticide component to enter, greatly improving the efficiency of preventing and controlling root-knot nematodes; the slow-release pesticide component includes, from the inside out, a pesticide component attached to the porous carrier and a degradable water-soluble slow-release film coated outside the porous carrier. Among them, the water-soluble slow-release film can slowly dissolve in humid soil and gradually release the pesticide component attached to the porous carrier to achieve the purpose of long-term prevention and control of root-knot nematodes; in addition, the porous carrier used in the present invention can also prevent soil compaction while releasing drugs, promote the growth of plants, and improve the disease resistance of plants.

[0010] To sum up, the composite agent for preventing and controlling root-knot nematodes provided by the present invention can not only prevent and control root-knot nematodes for a long time, has excellent prevention and control effects, does not need to be applied multiple times, is not affected by climate, but also can promote the growth and disease resistance of plants, effectively solving the problems of easy pollution and nematode drug resistance in chemical prevention and control of root-knot nematodes in the prior art, as well as the problems of slow effect, limited action range and easy influence by climate in biological prevention and control of root-knot nematodes.

[0011] Preferably, the porous carrier is a porous silicate-based carrier, and the specific preparation method includes the following steps: uniformly mixing dried vermiculite with an alkali solution, heating to 650°C - 750°C in an inert atmosphere, calcining, cooling, and grinding to obtain the porous silicate-based carrier.

[0012] The present invention calcines vermiculite after treatment with an alkali solution to prepare a porous silicate-based carrier. The obtained porous carrier can not only be used as a carrier for the pesticide component to assist in controlling the release of the pesticide component, but also play a role in loosening the soil, preventing soil compaction, and promoting the growth of plants; and vermiculite has low cost, simple operation, large specific surface area after calcination, and high loading fastness, and is an excellent carrier material.

[0013] Further preferably, the mass ratio of the vermiculite to the alkali solution is 5-10:1-3.

[0014] Further preferably, the temperature increase is carried out in a programmed temperature increase manner, and the heating rate of the programmed temperature increase is 10°C / min - 20°C / min.

[0015] Further preferably, the alkali solution is a sodium hydroxide solution with a concentration of 0.1mol / L - 0.5mol / L.

[0016] Further preferably, the calcination time is 1h - 2h.

[0017] Further preferably, the particle size of the porous silicate-based carrier is 30μm - 80μm.

[0018] Preferably, the water-soluble slow-release film comprises the following raw material components in parts by mass: 10-20 parts of carboxymethyl chitosan, 10-15 parts of polyvinyl alcohol, 0.5-1 part of film-forming aid, 1-3 parts of surfactant, 0.5-1 part of plasticizer, and 30-40 parts of deionized water.

[0019] The water-soluble slow-release film prepared by the present invention through specific raw material components has good water-soluble properties. Coating it on the surface of the porous silicate-based carrier loaded with pesticide components is equivalent to blocking the porous channels and enclosing the pesticide components therein. However, in a humid soil, the water-soluble slow-release film can gradually dissolve and gradually open the porous channels to achieve the purpose of controlling the release of pesticide components. Moreover, the water-soluble slow-release film also serves as a carrier for the inducer. When the film gradually dissolves, the inducer also enters the soil to induce the diseased plants.

[0020] Further preferably, the film-forming aid is any one or both of ethylene glycol isooctyl ether or diethylene glycol isooctyl ether.

[0021] Further preferably, the surfactant is sodium dodecyl sulfate and sodium dodecyl sulfonate with a mass ratio of 0.5:1 - 1.5.

[0022] Further preferably, the plasticizer is any one or more of glycerol, dioctyl phthalate or tributyl citrate.

[0023] Preferably, the inducer comprises the following raw material components in mass percentage: 0.01% - 0.05% of sodium selenite, 0.01% - 0.05% of vitamin C, 0.02% - 0.05% of amino acid chelate, 90% - 93% of polyvinyl alcohol, and the balance of water.

[0024] The main components of the inducer used in the present invention are nano-selenium obtained by reducing sodium selenite with vitamin C and amino acid chelates. The synergistic effect of the two can not only induce the expression of related genes in plants, improve the disease resistance of plants, but also change the permeability of the plant cell membrane, which is conducive to the full exertion of the activity of subsequent pesticide components.

[0025] Preferably, the pesticide components include the following raw material components in mass percentage: 0.03%-0.08% of thymus extract, 0.02%-0.04% of dracocephalum moldavica extract, 0.01%-0.04% of ivermectin, 0.05%-0.1% of ammonium salt, 0.01%-0.03% of synergist and the balance of water.

[0026] The present invention uses thymus extract, dracocephalum moldavica extract and ivermectin as the main pesticide components. Thymol, which is contained in thymus extract and dracocephalum moldavica extract, is an important substance for eliminating root-knot nematodes. Combining with ivermectin can greatly improve its insecticidal efficiency. The synergistic treatment of the three can achieve the purpose of efficiently controlling root-knot nematodes.

[0027] Preferably, the amino acid chelate is any one or two of amino acid chelated calcium or amino acid chelated magnesium.

[0028] Preferably, the ammonium salt is any one or two of ammonium sulfate or ammonium chloride.

[0029] Preferably, the synergist is emamectin benzoate and polyvinyl alcohol with a mass ratio of 1:2-5.

[0030] Preferably, the preparation method of the thymus extract includes the following steps: pulverize thymus, immerse it in an ethanol solution, carry out ultrasonic treatment, and filter to obtain the thymus extract.

[0031] More preferably, the ethanol solution is an ethanol solution with a mass fraction of 60%-75%.

[0032] More preferably, the mass-volume ratio of thymus to the ethanol solution is 1g:4mL-6mL.

[0033] More preferably, the immersion time is 1h-3h.

[0034] More preferably, the frequency of the ultrasonic treatment is 30kHz-35kHz, and the time of the ultrasonic treatment is 20min-40min.

[0035] Preferably, the preparation method of the dracocephalum moldavica extract includes the following steps: carry out water extraction and alcohol extraction on dracocephalum moldavica powder in sequence, and concentrate to obtain the dracocephalum moldavica extract.

[0036] Further preferably, the specific steps of the water extraction are as follows: Disperse the Dracocephalum moldavica powder in deionized water, reflux for 60 min - 80 min, and filter to obtain the water extract.

[0037] More preferably, the mass - to - volume ratio of the Dracocephalum moldavica powder to deionized water is 1 g:10 mL - 30 mL.

[0038] Further preferably, the specific steps of the ethanol extraction are as follows: Add absolute ethanol to the water extract, reflux for 25 min - 50 min, and obtain the ethanol extract.

[0039] More preferably, the volume ratio of the water extract to absolute ethanol is 1:3 - 5.

[0040] Further preferably, the temperature of the concentration is 95°C - 110°C.

[0041] In the second aspect of the present invention, a preparation method of the composite agent for preventing and controlling root - knot nematodes as described above is provided, including the following steps:

[0042] Step 1: Weigh each raw material component of the pesticide component according to the designed ratio, mix them evenly to obtain the pesticide component liquid; Immerse the porous carrier in the pesticide component liquid, perform ultrasonic treatment, and filter to obtain the first combined pesticide;

[0043] Step 2: Weigh each raw material component of the water - soluble slow - release film according to the designed ratio, mix them evenly to obtain the water - soluble slow - release film slurry; Immerse the first combined pesticide in the water - soluble slow - release film slurry, filter, and dry to obtain the slow - release pesticide component;

[0044] Step 3: Weigh each raw material component of the inducer according to the designed ratio, mix them evenly, add the slow - release pesticide component, oscillate, and dry to obtain the composite agent for preventing and controlling root - knot nematodes.

[0045] Preferably, in Step 1, the frequency of the ultrasonic treatment is 35 kHz - 45 kHz, and the time of the ultrasonic treatment is 20 min - 30 min.

[0046] Preferably, in Step 1, the drying temperature is 80°C - 95°C, and the drying time is 8 h - 12 h.

[0047] Preferably, in Step 2, the drying temperature is 70°C - 90°C, and the drying time is 2 h - 3 h.

[0048] Preferably, in Step 3, the oscillation time is 5 min - 20 min.

[0049] Preferably, in Step 3, the drying temperature is 90°C - 100°C, and the drying time is 3 h - 5 h.

[0050] In summary, the present invention provides a composite agent for preventing and controlling root-knot nematodes. By using an inducer to induce the expression of related genes in diseased plants, the disease resistance of the plants is improved, and the permeability of the plant cell membrane is changed, which is beneficial for the subsequent treatment of pesticide components, achieving the purpose of efficiently preventing and controlling root-knot nematodes. The slow-release pesticide component can not only control the long-term release of the drug, but also prevent soil compaction and promote plant growth. The composite agent provided by the present invention can not only prevent and control root-knot nematodes for a long time and efficiently, but also promote the improvement of the disease resistance of plants, and will not cause chemical pollution. At the same time, the control effect is not easily affected by climate, effectively solving the problems of chemical pollution and nematode drug resistance in the prior art for chemical control of root-knot nematodes, as well as the slow effect, limited action range and susceptibility to climate in biological control of root-knot nematodes, providing a new idea for the prevention and control of root-knot nematodes. Specific Embodiments

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0052] The preparation method of the thymus extract used in each embodiment and comparative example of the present invention specifically includes the following steps:

[0053] 50 g of thymus is crushed and immersed in 200 mL of 70% ethanol solution for 2 h. After immersion, ultrasonic treatment is carried out at a frequency of 30 kHz for 30 min, and then filtered to obtain the thymus extract.

[0054] The preparation method of the dracocephalum moldavica extract used in each embodiment and comparative example of the present invention specifically includes the following steps:

[0055] 10 g of dracocephalum moldavica powder is dispersed in 250 mL of deionized water, refluxed for 60 min, and filtered to obtain 60 mL of aqueous extract; 250 mL of absolute ethanol is added to the aqueous extract and refluxed for 40 min to obtain an ethanol extract; the ethanol extract is concentrated at 100 °C to obtain the dracocephalum moldavica extract.

[0056] Example 1

[0057] This example provides a composite agent for preventing and controlling root-knot nematodes, which specifically includes the following:

[0058] The composite agent includes a slow-release pesticide component and an inducer attached to its surface. Among them, the inducer includes the following raw material components: 0.03 g of sodium selenite, 0.05 g of vitamin C, 0.02 g of amino acid chelated calcium, 92.7 g of polyvinyl alcohol and 7.2 g of water;

[0059] The slow-release pesticide component includes a pesticide component, a porous carrier, and a water-soluble slow-release film; wherein, the pesticide component includes raw material components with the following mass percentages: 0.08 g of thymus extract, 0.03 g of dracocephalum moldavica extract, 0.04 g of ivermectin, 0.06 g of ammonium sulfate, 0.01 g of synergist, and 99.78 g of water, and the synergist is emamectin benzoate and polyvinyl alcohol with a mass ratio of 1:2;

[0060] The porous carrier is a porous silicate-based carrier, and the specific preparation method includes the following steps: Mix 100 kg of dried vermiculite with 20 g of 0.2 mol / L sodium hydroxide solution evenly, under an inert atmosphere, heat it to 700 °C at a heating rate of 20 °C / min, calcine for 1.5 h, quickly cool to room temperature, and grind to a particle size of 30 μm - 50 μm to obtain the porous silicate-based carrier;

[0061] The water-soluble slow-release film includes raw material components with the following mass parts: 15 g of carboxymethyl chitosan, 12 g of polyvinyl alcohol, 0.8 g of 2-ethylhexyl glycol ether, 2 g of surfactant, 1 g of glycerol, and 35 g of deionized water; wherein, the surfactant is sodium dodecyl sulfate and sodium dodecyl sulfonate with a mass ratio of 0.5:1.2;

[0062] The preparation method of the composite medicament includes the following steps:

[0063] Step 1: Weigh each raw material component of the pesticide component according to the designed ratio, mix evenly to obtain a pesticide component liquid, immerse the porous carrier in the pesticide component liquid, perform ultrasonic treatment at a frequency of 40 kHz for 20 min, filter, and dry at 90 °C for 10 h to obtain the first combined pesticide;

[0064] Step 2: Weigh each raw material component of the water-soluble slow-release film according to the designed ratio, mix evenly to obtain a water-soluble slow-release film slurry, immerse the first combined pesticide in the water-soluble slow-release film slurry, filter, and dry at 85 °C for 2.5 h to obtain the slow-release pesticide component;

[0065] Step 3: Weigh each raw material component of the inducer according to the designed ratio, mix evenly, add the slow-release pesticide component, oscillate for 10 min, and dry at 95 °C for 4 h to obtain the composite medicament for preventing and controlling root-knot nematodes.

[0066] Example 2

[0067] This example provides a composite medicament for preventing and controlling root-knot nematodes, which specifically includes the following content:

[0068] The composite agent includes a slow-release pesticide component and an inducer attached to the surface thereof, wherein the inducer includes the following raw material components: 0.05g of sodium selenite, 0.03g of vitamin C, 0.05g of amino acid chelated magnesium, 90.3g of polyvinyl alcohol and 9.57g of water;

[0069] The slow-release pesticide component includes a pesticide component, a porous carrier, and a water-soluble slow-release film; wherein the pesticide component includes the following raw material components in percentage by weight: 0.03g of thyme extract, 0.04g of cyperus rotundus extract, 0.01g of ivermectin, 0.1g of ammonium chloride, 0.03g of a synergist, and 99.79g of water, wherein the synergist is emamectin benzoate and polyvinyl alcohol in a mass ratio of 1:3;

[0070] The porous carrier is a porous silicate-based carrier, and the specific preparation method includes the following steps: 100 kg of dried vermiculite and 30 g of 0.15 mol / L sodium hydroxide solution are mixed uniformly, heated to 750° C. at a heating rate of 15° C. / min under an inert atmosphere, calcined for 1 hour, rapidly cooled to room temperature, and ground to a particle size of 50 μm-80 μm to obtain the porous silicate-based carrier;

[0071] The water-soluble sustained-release film comprises the following raw material components in parts by mass: 20 g of carboxymethyl chitosan, 10 g of polyvinyl alcohol, 0.5 g of diethylene glycol isooctyl ether, 2 g of a surfactant, 1 g of dioctyl phthalate, and 30 g of deionized water; wherein the surfactant is sodium lauryl sulfate and sodium lauryl sulfonate in a mass ratio of 0.5:1;

[0072] The preparation method of the composite medicament comprises the following steps:

[0073] Step 1: Weigh the raw material components of the pesticide component according to the designed ratio, mix them evenly to obtain a pesticide component liquid, immerse the porous carrier in the pesticide component liquid, ultrasonicate at a frequency of 45 kHz for 20 minutes, filter, and dry at 95° C. for 8 hours to obtain a first combination pesticide;

[0074] Step 2: Weigh the raw material components of the water-soluble slow-release film according to the designed ratio, mix them evenly to obtain a water-soluble slow-release film slurry, impregnate the first combination pesticide into the water-soluble slow-release film slurry, filter, and dry at 80° C. for 2.5 hours to obtain the slow-release pesticide component;

[0075] Step 3: Weigh the raw material components of the inducer according to the designed ratio, mix them evenly, add the slow-release pesticide component, shake for 7 minutes, and dry at 100° C. for 3.5 hours to obtain the composite agent for controlling root-knot nematodes.

[0076] Example 3

[0077] This embodiment provides a composite agent for preventing and controlling root-knot nematodes, which specifically includes the following content:

[0078] The composite agent includes a slow-release pesticide component and an inducer attached to its surface. Among them, the inducer includes the following raw material components: 0.01 g of sodium selenite, 0.01 g of vitamin C, 0.04 g of amino acid chelated calcium, 91.8 g of polyvinyl alcohol, and 8.14 g of water;

[0079] The slow-release pesticide component includes a pesticide component, a porous carrier, and a water-soluble slow-release film; among them, the pesticide component includes the following raw material components in mass percentage: 0.05 g of thymus extract, 0.04 g of dracocephalum moldavica extract, 0.04 g of ivermectin, 0.07 g of ammonium sulfate, 0.02 g of synergist, and 99.78 g of water. Among them, the synergist is emamectin benzoate and polyvinyl alcohol with a mass ratio of 1:5;

[0080] The porous carrier is a porous silicate-based carrier, and the specific preparation method includes the following steps: Mix 100 kg of dried vermiculite with 15 g of 0.5 mol / L sodium hydroxide solution evenly, and under an inert atmosphere, heat it to 650 °C at a heating rate of 10 °C / min, calcine for 2 h, quickly cool to room temperature, and grind to a particle size of 30 μm - 80 μm to obtain the porous silicate-based carrier;

[0081] The water-soluble slow-release film includes the following raw material components in mass parts: 10 g of carboxymethyl chitosan, 15 g of polyvinyl alcohol, 0.5 g of ethylene glycol isooctyl ether, 1 g of surfactant, 0.5 g of tributyl citrate, and 40 g of deionized water; among them, the surfactant is sodium dodecyl sulfate and sodium dodecyl sulfonate with a mass ratio of 0.5:1.5;

[0082] The preparation method of the composite agent includes the following steps:

[0083] Step 1: Weigh each raw material component of the pesticide component according to the designed ratio, mix them evenly to obtain a pesticide component solution, immerse the porous carrier in the pesticide component solution, perform ultrasonic treatment at a frequency of 35 kHz for 30 min, filter, and dry at 80 °C for 12 h to obtain the first combined pesticide;

[0084] Step 2: Weigh each raw material component of the water-soluble slow-release film according to the designed ratio, mix them evenly to obtain a water-soluble slow-release film slurry, immerse the first combined pesticide in the water-soluble slow-release film slurry, filter, and dry at 75 °C for 3 h to obtain the slow-release pesticide component;

[0085] Step 3: Weigh each raw material component of the inducer according to the designed ratio, mix them evenly, add the slow-release pesticide component, oscillate for 15 min, and dry at 90 °C for 5 h to obtain the compound agent for preventing and controlling root-knot nematodes.

[0086] Comparative Example 1

[0087] This comparative example provides a compound agent for preventing and controlling root-knot nematodes, which is different from Example 1 in that there is no inducer, and the specific content is as follows.

[0088] The compound agent is a slow-release pesticide agent, which includes a pesticide component, a porous carrier and a water-soluble slow-release film; wherein, the pesticide component includes raw material components with the following mass percentages: 0.08 g of thymus extract, 0.03 g of dracocephalum moldavica extract, 0.04 g of ivermectin, 0.06 g of ammonium sulfate, 0.01 g of synergist and 99.78 g of water, wherein the synergist is emamectin benzoate and polyvinyl alcohol with a mass ratio of 1:2;

[0089] The porous carrier is a porous silicate-based carrier, and the specific preparation method includes the following steps: Mix 100 kg of dried vermiculite with 20 g of 0.2 mol / L sodium hydroxide solution evenly, and under an inert atmosphere, heat it to 700 °C at a heating rate of 20 °C / min, calcine for 1.5 h, quickly cool to room temperature, and grind to a particle size of 30 μm - 50 μm to obtain the porous silicate-based carrier;

[0090] The water-soluble slow-release film includes raw material components with the following mass parts: 15 g of carboxymethyl chitosan, 12 g of polyvinyl alcohol, 0.8 g of ethylene glycol isooctyl ether, 2 g of surfactant, 1 g of glycerol and 35 g of deionized water; wherein, the surfactant is sodium dodecyl sulfate and sodium dodecyl sulfonate with a mass ratio of 0.5:1.2;

[0091] The preparation method of the compound agent for preventing and controlling root-knot nematodes includes the following steps:

[0092] Step 1: Weigh each raw material component of the pesticide component according to the designed ratio, mix them evenly to obtain a pesticide component solution, immerse the porous carrier in the pesticide component solution, perform ultrasonic treatment at an ultrasonic frequency of 40 kHz for 20 min, filter, and dry at 9 °C for 10 h to obtain the first combined pesticide;

[0093] Step 2: Weigh each raw material component of the water-soluble slow-release film according to the designed ratio, mix them evenly, add the slow-release pesticide component, oscillate for 10 min, and dry at 85 °C for 2.5 h to obtain the compound agent for preventing and controlling root-knot nematodes.

[0094] Comparative Example 2

[0095] This comparative example provides a compound agent for controlling root-knot nematodes. The difference from Example 1 is that sodium selenite and vitamin C in the inducer are replaced with oligochitosan, and the specific contents are as follows.

[0096] The compound agent includes a slow-release pesticide component and an inducer attached to its surface. The inducer includes the following raw material components: 0.08 g of oligochitosan, 0.02 g of amino acid chelated calcium, 92.7 g of polyvinyl alcohol, and 7.2 g of water;

[0097] The slow-release pesticide component includes a pesticide component, a porous carrier, and a water-soluble slow-release film; wherein, the pesticide component includes the following raw material components in mass percentage: 0.08 g of thymus extract, 0.03 g of dracocephalum moldavica extract, 0.04 g of ivermectin, 0.06 g of ammonium sulfate, 0.01 g of synergist, and 99.78 g of water, wherein the synergist is emamectin benzoate and polyvinyl alcohol with a mass ratio of 1:2;

[0098] The porous carrier is a porous silicate-based carrier. The specific preparation method includes the following steps: Mix 100 kg of dried vermiculite with 20 g of 0.2 mol / L sodium hydroxide solution evenly, and under an inert atmosphere, heat it to 700 °C at a heating rate of 20 °C / min, calcine for 1.5 h, quickly cool to room temperature, and grind to a particle size of 30 μm - 50 μm to obtain the porous silicate-based carrier;

[0099] The water-soluble slow-release film includes the following raw material components in parts by mass: 15 g of carboxymethyl chitosan, 12 g of polyvinyl alcohol, 0.8 g of ethylene glycol isooctyl ether, 2 g of surfactant, 1 g of glycerol, and 35 g of deionized water; wherein, the surfactant is sodium dodecyl sulfate and sodium dodecyl sulfonate with a mass ratio of 0.5:1.2;

[0100] The preparation method of the compound agent for controlling root-knot nematodes includes the following steps:

[0101] Step 1: Weigh each raw material component of the pesticide component according to the designed ratio, mix evenly to obtain a pesticide component liquid, immerse the porous carrier in the pesticide component liquid, perform ultrasonic treatment at an ultrasonic frequency of 40 kHz for 20 min, filter, and dry at 90 °C for 10 h to obtain the first combined pesticide;

[0102] Step 2: Weigh each raw material component of the water-soluble slow-release film according to the designed ratio, mix evenly to obtain a water-soluble slow-release film slurry, immerse the first combined pesticide in the water-soluble slow-release film slurry, filter, and dry at 85 °C for 2.5 h to obtain the slow-release pesticide component;

[0103] Step 3: Weigh each raw material component of the inducer according to the designed ratio, mix them evenly, add the slow-release pesticide component, oscillate for 10 min, and dry at 95 °C for 4 h to obtain the compound agent for preventing and controlling root-knot nematodes.

[0104] Comparative Example 3

[0105] This comparative example provides a compound agent for preventing and controlling root-knot nematodes. The difference from Example 1 is that both the thymol extract and the dracocephalum moldavica extract in the pesticide component are replaced with an equal amount of thiazolezine, and other components and preparation processes remain unchanged, which will not be elaborated here.

[0106] Comparative Example 4

[0107] This comparative example provides a commercially available agent for preventing and controlling root-knot nematodes, with the brand name of "Charcoal Seller - Wireless Soothing".

[0108] In order to further reflect the technical effects of the present invention, the present invention conducted pot control efficacy tests and field control efficacy tests on the compound agents for preventing and controlling root-knot nematodes obtained in Examples 1-3 and Comparative Examples 1-4. The test object was cucumber, and the specific contents were as follows.

[0109] Pot control efficacy test

[0110] Set 8 treatment groups, one group as the blank control, and the other 7 groups were respectively applied with the compound agents provided in Examples 1-3 and Comparative Examples 1-4. Retrieve the rhizosphere soil (5 cm - 20 cm soil layer) of crops from the greenhouse where root-knot nematodes occur frequently, and sub-pack it in cultivation pots. The specification of the cultivation pots is length * width * height = 24 cm * 19.5 cm * 26.5 cm, 500 g per pot. After sub-packing, detect the number of root-knot nematodes and eggs in each pot of soil. Sow cucumber seeds in the cultivation pots, mix 0.3 g of the compound agent with 10 kg of soil and apply the medicine, with a depth ≥ 15 cm, and conduct conventional management. Sampling of the potted soil was carried out at 0, 10 d, 20 d, 30 d, and 50 d after applying the medicine. Take 100 g of rhizosphere soil, and separate nematodes by the improved Baermann funnel method. Collect the nematode liquid with a small glass bottle, after standing for 2.5 h, suck out two-thirds of the supernatant, and add water at 100 °C to kill the nematodes. Observe with a stereomicroscope and count. Calculate the reduction rate of the pest population and the control effect.

[0111] Calculation formula: Reduction rate of the pest population = (number of pests before treatment - number of pests after treatment) / number of pests before treatment × 100%;

[0112] Control effect of the pest population = (reduction rate of the pest population in the treatment - reduction rate of the pest population in the blank) / (1 - reduction rate of the pest population in the blank) × 100%; The results are shown in Table 1.

[0113] Field control efficacy test

[0114] Eight treatment groups were set up, one group was a blank control, and the other seven groups were respectively treated with the compound agents provided by Examples 1-3 and Comparative Examples 1-4. Each treatment group had an area of 10 m 2 Each group planted 50 cucumber seedlings, mixed 30g of the compound pesticide with 1000kg of soil, and applied the pesticide at a depth of ≥15cm. During the harvest period, soil samples of 5cm-15cm were randomly collected from 10 points in each group to investigate the number of second-instar root-knot nematodes in the soil and the degree of root disease, and the disease index and control effect were calculated. The disease severity grading standard is as follows: Level 0, no root knots on the roots; Level 1, mild infection, only a few small root knots, and a root knot rate of ≤3%; Level 2, a root knot rate of 3%-25%; Level 3, many root knots, and a root knot rate of 25%-50%; Level 4, there are secondary root knots on the nodules, and a root knot rate of 50%-75%; Level 5, the root knots are connected to each other into root knot clumps, and the root knot rate is ≥75%.

[0115] Calculation method: disease index (%) = ∑ (number of diseased plants at each level × relative level value) / (total number of plants surveyed × 5) × 100;

[0116] Control effect (%) = (disease index of blank control area - disease index of treated area) / (disease index of blank control area) × 100;

[0117] At the same time, the fresh weight of the cucumber fruits of each plant was measured on the 15th day of the harvest period. Among them, 5 samples were taken from a single cucumber plant using the five-point sampling method, and the fresh weight of the cucumber fruits of the single plant was averaged. Each treatment group was harvested separately, and the total yield of each treatment group at the final harvest was recorded. The results are shown in Table 2.

[0118] Table 1 Potted plant prevention effect test results

[0119]

[0120] Table 2 Field test results

[0121]

[0122] As can be seen from Tables 1 and 2, the composite agent for controlling root-knot nematodes provided by the embodiments of the present invention provides long-term control with only a single application, achieving a population control efficiency of 91.33% at 50 days. Furthermore, when applied to field control, the control efficiency also reached over 88%. This indicates that the composite agent for controlling root-knot nematodes provided by the present invention can effectively improve the control efficiency of root-knot nematodes and promote crop growth.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite agent for controlling root-knot nematodes, characterized in that: The composite agent is composed of a slow-release pesticide component and an inducer attached to the surface thereof; The inducer is composed of the following raw material components: sodium selenite, vitamin C, amino acid chelate and polyvinyl alcohol; The slow-release pesticide components are, from the inside out, the pesticide component attached to the porous carrier and the degradable water-soluble slow-release film coated on the outside of the porous carrier; the pesticide components are composed of the following raw materials: thyme extract, cyperus rotundus extract, ivermectin, ammonium salt and synergist; The porous carrier is a porous silicate-based carrier, and the specific preparation method includes the following steps: mixing the dried vermiculite with an alkaline solution, heating to 650° C.-750° C. under an inert atmosphere, calcining, cooling, and grinding to obtain the porous silicate-based carrier; The water-soluble sustained-release film is composed of the following raw material components in parts by mass: 10-20 parts of carboxymethyl chitosan, 10-15 parts of polyvinyl alcohol, 0.5-1 parts of a film-forming aid, 1-3 parts of a surfactant, 0.5-1 parts of a plasticizer, and 30-40 parts of deionized water; The film-forming aid is any one or both of ethylene glycol isooctyl ether and diethylene glycol isooctyl ether; The surfactant is sodium lauryl sulfate and sodium lauryl sulfonate in a mass ratio of 0.5:1-1.5; The plasticizer is any one or more of glycerol, dioctyl phthalate or tributyl citrate; The amino acid chelate is any one or both of amino acid chelated calcium and amino acid chelated magnesium; The ammonium salt is any one or both of ammonium sulfate and ammonium chloride; The synergist is emamectin benzoate and polyvinyl alcohol in a mass ratio of 1:2-5; The preparation method of the thyme extract comprises the following steps: crushing thyme, soaking in an ethanol solution, ultrasonicating, and filtering to obtain the thyme extract; The preparation method of the Herba Lycopersicon esculentum extract comprises the following steps: extracting Herba Lycopersicon esculentum powder with water and alcohol in sequence, and concentrating the extract to obtain the Herba Lycopersicon esculentum extract.

2. The composite agent for controlling root-knot nematodes according to claim 1, wherein: The mass ratio of the vermiculite to the alkaline solution is 5-10:1-3; and / or The temperature is increased by programmed temperature increase, and the rate of the programmed temperature increase is 10°C / min-20°C / min; and / or The alkaline solution is a 0.1 mol / L-0.5 mol / L sodium hydroxide solution; and / or The calcination time is 1h-2h; and / or The particle size of the porous silicate-based carrier is 30 μm-80 μm.

3. The composite agent for controlling root-knot nematodes according to claim 1, wherein: The inducer is composed of the following raw material components in percentage by weight: 0.01%-0.05% sodium selenite, 0.01%-0.05% vitamin C, 0.02%-0.05% amino acid chelate, 90%-93% polyvinyl alcohol and the balance water; and / or The pesticide component is composed of the following raw material components in percentage by mass: 0.03%-0.08% of thyme extract, 0.02%-0.04% of cyperus rotundus extract, 0.01%-0.04% of ivermectin, 0.05%-0.1% of ammonium salt, 0.01%-0.03% of synergist and the balance of water.

4. The method for preparing the composite agent for controlling root-knot nematodes according to any one of claims 1 to 3, wherein: The steps include: Step 1: Weighing the raw material components of the pesticide component according to the designed ratio, mixing them evenly to obtain a pesticide component liquid; immersing the porous carrier in the pesticide component liquid, sonicating, and filtering to obtain a first combined pesticide; Step 2: Weighing the raw material components of the water-soluble slow-release film according to the designed ratio, mixing them evenly to obtain a water-soluble slow-release film slurry; impregnating the first combination pesticide into the water-soluble slow-release film slurry, filtering, and drying to obtain the slow-release pesticide component; Step 3: Weigh the raw material components of the inducer according to the designed ratio, mix them evenly, add the slow-release pesticide component, shake, and dry to obtain the composite agent for controlling root-knot nematodes.

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