Nanometer humic acid and azadirachtin coupled biopesticide and preparation method thereof

Abstract

The invention belongs to the technical field of novel biopesticides, and relates to a nano-humic acid and azadirachtin coupled biopesticide and a preparation method thereof.The nano-humic acid and azadirachtin coupled biopesticide is screened out by experimenting and optimizing the concentration and proportion of nano-humic acid and azadirachtin in the nano-humic acid and azadirachtin coupled biopesticide, and the nano-humic acid and azadirachtin coupled biopesticide is used for preparing the nano-humic acid and azadirachtin coupled biopesticide. The water-soluble fertilizer is prepared from the following components in parts by volume: 50 parts of a 2% nano humic acid solution, 1 part of a 1% azadirachtin solution, 40 parts of ddH2O and 9 parts of DMF (Dimethyl Formamide). According to the prepared nano humic acid and azadirachtin coupled biopesticide, particles of the nano humic acid can be minimized and uniform, and the nano humic acid and azadirachtin coupled biopesticide has the dual effects of biopesticide and bio-fertilizer, does not contain organic solvents with high toxicity to human bodies, such as methylbenzene and xylene, and is safer to use.

Description

Technical Field

[0001] The invention belongs to the technical field of novel biological pesticides, and in particular relates to a nano-humic acid and azadirachtin coupled biological pesticide and a preparation method thereof. Background Art

[0002] In the world's agricultural production process, in order to ensure the output of agricultural products, chemical pesticides are the most diverse and easy-to-use measures, including organophosphorus pesticides, carbamate enzyme pesticides, nicotine pesticides, etc., which play a pivotal role in agricultural pest control. More than 6 million tons of chemical pesticides are sprayed into the natural environment every year. With the large-scale and irrational use of chemical pesticides, while protecting the stable and high yield of crops, it also inevitably brings great harm and many negative effects.

[0003] Chemical pesticides are highly toxic, causing serious excess of pesticide residues in agricultural products, posing a huge threat to human food safety; they can also accidentally kill a large number of beneficial natural enemies, and penetrate into the soil and water, causing environmental pollution and affecting human health. Long-term use of a certain type of chemical pesticide can easily cause pests to develop resistance, resulting in a sharp increase in the amount of chemical pesticides used. This vicious cycle, on the one hand, greatly increases the economic burden on farmers, and on the other hand, seriously pollutes the ecological environment. my country is currently the world's largest producer and user of pesticides, with an annual pesticide market share (including imports and exports) of approximately 200 billion yuan, of which 95% is chemical pesticides.

[0004] In response to these problems of chemical pesticides, many developed countries and regions have begun to ban the promotion and use of chemical agents. With the development of economy and society, people's requirements for quality of life are increasing, and consumers' requirements for agricultural product quality and safety and awareness of protecting the ecological environment are increasing. The call for the development and use of biological pesticides with good environmental compatibility and harmless to humans is growing. The development and promotion of biological pesticides has become the main direction of the development of green agriculture and organic agriculture in the world today. Among them, the processing and utilization of natural products has become a hot spot in the research and development of biological pesticides.

[0005] Naturally occurring biopesticides are generally low in toxicity, highly environmentally compatible, quickly degraded, and less likely to accumulate toxicity in the ecological environment. Biopesticides can ensure the safety of high-end agricultural products such as green food and organic food, which are in growing demand for humankind, avoid or mitigate the negative impact of chemical pesticides, and make it difficult for pests to develop resistance. Therefore, biopesticides, labeled as "green, environmentally friendly, non-toxic, harmless, efficient, and safe," have become a trend in the development of the pesticide industry.

[0006] China is the first country in the world to use plant-based pesticides. The book "Poisonous Plants in China" lists more than 1,300 species. According to surveys and statistics, there are more than 400 species of plants from more than 30 families such as Meliaceae, Asteraceae, Leguminosae, Celastraceae, and Euphorbiaceae that can be used as pesticides in my country. Among the many available plant-based pesticides, neem (Azadirachta Indica A.Juss.) is one of the few plants that can be directly processed and used as a natural insecticide.

[0007] Azadirachtin extracted from neem seeds has the highest insecticidal activity, including compounds such as azadirachtin A, B, C, D, E, F, G, H, I, and J. According to a large number of experiments by scientists, azadirachtin has been confirmed to have insecticidal activity against more than 400 species of agricultural, forestry, storage and sanitary pests in more than 10 orders, including Lepidoptera, Culicidae, Homoptera, Hemiptera, Orthoptera, Diptera, Hymenoptera, Blattodea, Phasmatodea, and Isoptera, and also has a good killing effect on a variety of nematodes and fungi. The toxic activity and mechanism of action of azadirachtin on pests are mainly manifested in making insects refuse to eat, avoid and inhibit the growth and development of insects, interfering with the endocrine system of pests, preventing the larvae from molting and pupating normally, and causing the death of pests. It has the characteristics of pests not easily developing resistance, long lasting effect, easy degradation in the environment and safety to non-target organisms. Long-term use can effectively control the density and size of pest populations. It is a new type of environmentally friendly insecticide with broad spectrum, high efficiency, low toxicity and low residue, which is the most studied and recognized by countries around the world.

[0008] The late Chinese botanist, Academician Zhao Shanhuan, spoke highly of neem, which is a representative of botanical insecticides. It almost meets all the standards required for an ideal pesticide: broad spectrum, little interference with natural enemies, no obvious vertebrate toxicity or plant medicine, rapid degradation in the environment, abundant regional resources, and renewable, making it a relatively perfect insecticide.

[0009] However, azadirachtin is unstable to light and heat and has very low water solubility. In order to solve this problem, azadirachtin products in most countries in the world are currently emulsifiable concentrates. The most fatal disadvantage of emulsifiable concentrates is that they often use toxic toluene, xylene, etc. as organic solvents, which poses a great safety hazard to humans, plants, animals and the ecological environment.

[0010] Humus is the main part of soil organic matter and is a black amorphous organic colloid. Humus is not only the main source of soil nutrients, but also has an important impact on the physical, chemical and biological properties of the soil. It is one of the indicators of soil fertility. Humus can exist in the soil in the form of free humic acid and humic acid salts, or it can be tightly combined with mineral clay particles in a gel state to become an important colloidal substance. The supramolecular structure of humic acid contains substances similar to auxins, about 240 kinds of which can approach plant cells and extracellular receptors, thereby increasing the activity of proton pumps.

[0011] Humic acid and its products have many uses: in agriculture, humic acid fertilizers made by combining with nitrogen, phosphorus, potassium and other elements (for example, humic acid can be made into ammonium humate fertilizer by neutralizing humic acid with ammonia) have the functions of increasing fertilizer efficiency, improving soil, stimulating crop growth, and improving the quality of agricultural products; nitrohumic acid can be used as an acidifier for rice seedling cultivation; humic acid magnesium, humic acid zinc, and humic acid urea iron have good effects in supplementing soil magnesium deficiency, corn zinc deficiency, and fruit tree iron deficiency, respectively. Summary of the invention

[0012] The purpose of the present invention is to provide a nano-humic acid and azadirachtin coupled biological pesticide and a preparation method thereof, so as to solve the problem that the azadirachtin products of the emulsifiable concentrate formulations proposed in the above background technology often use toxic toluene, xylene, etc. as organic solvents, which poses a great safety hazard to humans, plants, animals and the ecological environment.

[0013] In order to achieve the above technical objectives, the technical solution of the present invention is: The invention provides a nano humic acid and azadirachtin coupled biological pesticide, which comprises the following components by volume: 50 parts of 2% nano humic acid solution, 1 part of 1% azadirachtin solution, 40 parts of ddH2O and 9 parts of DMF.

[0014] As an improvement, the preparation method of 1% azadirachtin is: take 1 mg of azadirachtin and dissolve it in 99 mg of DMF to prepare 1% azadirachtin.

[0015] As a further improvement, the preparation method of the 2% nano-humic acid is: take 2 mg of nano-humic acid and dissolve it in 98 mg of ddH2O to prepare 2% nano-humic acid.

[0016] The present invention also provides a method for preparing a nano-humic acid and azadirachtin coupled biological pesticide, wherein 50 μL of 2% nano-humic acid and 1 μL of 1% azadirachtin are mixed with ddH2O and DMF.

[0017] As a further improvement, in the nano-humic acid and azadirachtin coupled biological pesticide, the volume ratio of ddH2O to DMF is 9:1.

[0018] Due to the adoption of the above technical solution, the beneficial effects of the present invention are: The invention screens out the nano-humic acid and azadirachtin coupled biological pesticide by experimenting and optimizing the concentration and ratio of the nano-humic acid and azadirachtin in the nano-humic acid and azadirachtin coupled biological pesticide, and can make the nano-humic acid particles reach the minimum and uniformity.

[0019] The nano humic acid and azadirachtin coupled biological pesticide prepared by the invention has the dual functions of biological pesticide and biological fertilizer, and does not contain organic solvents such as toluene and xylene that are highly toxic to human body, so it is safer to use. DETAILED DESCRIPTION

[0022] Example 1 The preparation method of the nano-humic acid and azadirachtin coupled biopesticide with a volume fraction of 1% azadirachtin solution being 0% is as follows: S1: Dissolve 1 mg of azadirachtin in 99 mg of DMF to prepare a 1% azadirachtin solution for later use; S2: Dissolve 2 mg of nano-humic acid in 98 mg of ddH2O to prepare a 2% nano-humic acid solution for later use; S3: Take 10 mg of the 1% azadirachtin solution prepared in step S1, dissolve it in 90 mg of DMF, dilute it to a 0.1% azadirachtin solution, and set aside; S4: Take 50 μL of the 2% nano-humic acid solution in step S2, 40 μL of ddH2O and 10 μL of DMF and mix them to form a 1% azadirachtin solution with a volume fraction of 0% nano-humic acid and azadirachtin coupled biopesticide.

[0023] Example 2 The preparation method of the biopesticide coupled with nano-humic acid and azadirachtin with a volume fraction of 0.3% of azadirachtin solution is as follows: S1: Dissolve 1 mg of azadirachtin in 99 mg of DMF to prepare a 1% azadirachtin solution for later use; S2: Dissolve 2 mg of nano-humic acid in 98 mg of ddH2O to prepare a 2% nano-humic acid solution for later use; S3: Take 10 mg of the 1% azadirachtin solution prepared in step S1, dissolve it in 90 mg of DMF, dilute it to a 0.1% azadirachtin solution, and set aside; S4: Take 50 μL of the 2% nano-humic acid solution in step S2, 3 μL of the 0.1% azadirachtin solution in step S3, 40 μL of ddH2O and 7 μL of DMF and mix them to form a 1% azadirachtin solution with a volume fraction of 0.3% of nano-humic acid and azadirachtin coupled biopesticide.

[0024] Example 3 The invention discloses a method for preparing a biopesticide coupled with nano-humic acid and azadirachtin with a volume fraction of 0.5% of azadirachtin solution.

[0025] The preparation method of this embodiment is the same as that of Example 2, except that the amount of 0.1% azadirachtin solution added in step S4 of this embodiment is 5 μL.

[0026] Example 4 The invention discloses a method for preparing a biopesticide coupled with nano-humic acid and azadirachtin with a volume fraction of 0.7% of azadirachtin solution.

[0027] The preparation method of this embodiment is the same as that of Example 2, except that the amount of the 0.1% azadirachtin solution added in step S4 of this embodiment is 7 μL.

[0028] Example 5 The method for preparing a 1% azadirachtin solution with a volume fraction of 1% nano-humic acid and azadirachtin coupled biological pesticide has the following specific steps: S1: Dissolve 1 mg of azadirachtin in 99 mg of DMF to prepare a 1% azadirachtin solution for later use; S2: Dissolve 2 mg of nano-humic acid in 98 mg of ddH2O to prepare a 2% nano-humic acid solution for later use; S3: Take 50 μL of the 2% nano-humic acid solution in step S2, 1 μL of the 1% azadirachtin solution in step S3, 40 μL of ddH2O and 7 μL of DMF and mix them to form a 1% azadirachtin solution with a volume fraction of 1% nano-humic acid and azadirachtin coupled biopesticide.

[0029] Example 6 The invention discloses a method for preparing a biopesticide coupled with nano-humic acid and azadirachtin with a volume fraction of 3% of azadirachtin solution.

[0030] The preparation method of this embodiment is the same as that of Embodiment 5, except that the amount of 1% azadirachtin solution added in step S3 of this embodiment is 3 μL.

[0031] Example 7 The invention discloses a method for preparing a biopesticide coupled with nano-humic acid and azadirachtin with a volume fraction of 5% of azadirachtin solution.

[0032] The preparation method of this embodiment is the same as that of Embodiment 5, except that the amount of 1% azadirachtin solution added in step S3 of this embodiment is 5 μL.

[0033] The present invention also performs electron microscope scanning photography on the nano-humic acid and azadirachtin coupled biopesticides with different azadirachtin contents in the 1% azadirachtin solutions prepared in Examples 1 to 7, and the photography steps are as follows: Take 10 μL of the nano-humic acid and azadirachtin coupled biological pesticide in Examples 1 to 7 respectively, drop it on a silicon wafer, dry the solvent, and then scan it with an electron microscope. According to the analysis of the scanning results, as the doping ratio of azadirachtin increases, the size of humic acid gradually decreases. From the 1200 magnification screen, the undoped humic acid has a very clear shape, while the doping of azadirachtin makes the humic acid gradually blurred and flat; from the 5500 magnification screen, the 1% doping ratio can clearly see that the humic acid becomes smaller particles. From the 7500 magnification screen, the 1% doping ratio can clearly see that the humic acid becomes smaller particles. Therefore, the nano-humic acid and azadirachtin coupled biological pesticide prepared in Example 5 is the best ratio, which can make the nano-humic acid particles minimum and uniform.

[0034] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A nano-humic acid and azadirachtin coupled biological pesticide, characterized in that: The composition comprises the following components by volume: 50 parts of 2% nano humic acid solution, 1 part of 1% azadirachtin solution, 40 parts of ddH2O and 9 parts of DMF.

2. The nano-humic acid and azadirachtin coupled biological pesticide according to claim 1, characterized in that: The preparation method of 1% azadirachtin is as follows: 1 mg of azadirachtin is dissolved in 99 mg of DMF to prepare 1% azadirachtin.

3. The nano-humic acid and azadirachtin coupled biological pesticide according to claim 1, characterized in that: The preparation method of the 2% nano-humic acid is as follows: 2 mg of nano-humic acid is dissolved in 98 mg of ddH2O to prepare 2% nano-humic acid.

4. A method for preparing the nano-humic acid and azadirachtin coupled biological pesticide according to claim 1, characterized in that: Take 50 μL of 2% nano-humic acid and 1 μL of 1% azadirachtin and mix them evenly with ddH2O and DMF to form nano-humic acid and azadirachtin coupled biopesticide.

5. The method for preparing the nano-humic acid and azadirachtin coupled biological pesticide according to claim 4, characterized in that: In the nano-humic acid and azadirachtin coupled biological pesticide, the volume ratio of ddH2O and DMF is 9:1.