Citral biopesticide for preventing and treating wheat rhizome diseases and application of citral biopesticide

Abstract

The invention discloses a citral biopesticide for preventing and treating wheat rhizome diseases and application of the citral biopesticide. Wheat sharp eyespot and wheat stem rot are soil-borne fungal diseases, the disease control effect is weakened due to high-frequency use of chemical bactericides, the screened plant-source volatile metabolite citral and tebuconazole are mixed, the use amount of tebuconazole can be effectively reduced, the good control effect on diseases is achieved, and the pesticide composition has a good application prospect. Meanwhile, the safety to wheat production and the environment is improved.

Description

Technical Field

[0001] The invention relates to the field of agricultural plant protection, and in particular to a citral biological pesticide for preventing and treating wheat root and stem diseases and an application thereof. Background Art

[0002] Wheat sharp eyespot, also known as wheat eye spot disease, is a soil-borne fungal disease that causes serious damage to wheat growth, development and yield. Wheat sharp eyespot is mainly caused by Rhizoctonia cerealis (R.cerealis). The disease occurs in a wide range, not only in the main wheat-producing areas of my country, but also throughout the world's wheat-growing areas. It is a common disease in wheat areas. In severe cases, the yield reduction is as high as 30% to 40% or more. The pathogen of wheat sharp eyespot overwinters in diseased remains and soil. It has a very strong ability to adapt to the environment. Under suitable temperature conditions, it becomes a source of infection in the following year. Wheat may be infected with sheath blight from germination to jointing and heading. Sheath blight not only infects wheat, but also harms food crops such as corn and rice. At present, the use of chemical means to control wheat stripe blight is a fast and effective control measure. In production, a combination of seed dressing and spraying is often used to control wheat stripe blight. Commonly used agents include triazoles, such as Tebuconazole, Triadimenol, Triadimefon, etc.; however, chemical pesticides are difficult to metabolize normally in the environment, and are easily retained in the soil and absorbed by plants, and are continuously accumulated through the food chain. They are highly lethal to natural enemies and cause bacterial resistance.

[0003] Wheat crown rot, also known as "wheat cancer", is a fungal soil-borne disease that has been developing into a global wheat disease distributed in arid and semi-arid areas around the world. As a new type of wheat disease that has become popular in my country in recent years, wheat crown rot mainly occurs in Henan, Hebei, Anhui, Shandong, Jiangsu and other places. Since the discovery of wheat crown rot in Shandong Province in 2015, the disease has rapidly spread throughout the province and has continued to worsen, seriously endangering the planting safety and production quality of wheat. Wheat crown rot is caused by a variety of pathogenic fungi, the main pathogens of which are F. pseudograminearum and F. graminearum. The disease can occur from wheat seedlings to adult plants, throughout all wheat growth periods. Infection in the seedling stage leads to rotten seeds and dead seedlings, browning of the leaf sheaths and stems at the base of the stem, and browning and rot of the roots. In the late stage of the disease, the plants produce dry and white wheat ears, and the grains gradually stop filling, resulting in a reduction in wheat production, which seriously affects wheat yield and quality. Currently, the main means of preventing and controlling wheat stem rot is comprehensive prevention and control that combines agricultural prevention and chemical prevention.

[0004] Long-term single use of chemical agents will make pathogens resistant, cause environmental pollution, and be detrimental to ecological balance. In disease prevention and control, biological control can effectively reduce the use of pesticides, is beneficial to the ecological environment of the soil, and is in line with the current concept of green plant protection. Beneficial microorganisms, such as bacteria and fungi, are rich sources of various natural compounds that control plant diseases to varying degrees. Microorganisms that inhibit plant pathogens produce natural compounds, including secondary metabolites (Zubair, et al., 2021). Therefore, in the future integrated prevention and control of wheat diseases, the development and research of biocontrol agents combined with traditional chemical pesticides can not only reduce the development of resistance and be beneficial to the environment, but also maximize the benefits of integrated prevention and control.

[0005] Citral, also known as 2,6-dimethyl-2,6-octadienal and geranyl aldehyde, has a molecular formula of C 10 H 16 O, colorless or slightly yellow liquid, with a strong lemon aroma, is one of the most important representatives of open-chain monoterpenes, exists in maple oil and litsea cubeba oil, can be separated from citrus essential oil and litsea cubeba oil, and can also be obtained through artificial synthesis. In summary, a large number of studies have shown that citral has a broad spectrum of antibacterial activity, effectively slows down the post-harvest decay of fruits and vegetables, prolongs their shelf life, and has a good inhibitory effect on many pathogenic fungi.

[0006] Octanal, also known as 1-octanal and n-octanal, is a colorless liquid with a strong fruity aroma. It can be used as a food flavoring, a soap detergent flavoring, and an intermediate in organic synthesis. Its molecular formula is C8H 16 O, belongs to the fatty aldehyde class, and is commonly found in essential oils of tea trees, citrus, etc. Octanal has a good antibacterial effect on pathogens and attracts insects, but there are few reports on the use of octanal in plant disease prevention and control, and its antibacterial mechanism needs to be further improved and explored. Summary of the invention

[0007] In recent years, soil-borne fungal diseases, mainly wheat stem rot and sheath blight, have continued to expand and spread, becoming the main factor restricting the high and stable yield of wheat. Due to the lack of corresponding high-resistant varieties in production, the prevention and control of wheat soil-borne diseases is still mainly chemical control, but the high frequency use of chemical fungicides has gradually increased the resistance of pathogens and weakened the effect of disease control. At present, the application of plant-derived metabolites and microbial-derived metabolites in disease control has gradually become a hot topic of concern. Plants and their secondary metabolites citral and microorganisms and their secondary metabolites octanal have potential good antibacterial components and have good effects in fruit and vegetable preservation, disease control and grain storage. In addition, because it is safe for the environment, not easy to produce drug residues and has good antibacterial effect, it has important research value in the development and application of natural antibacterial agents for plant diseases. However, there are few reports on the application of such metabolites in the prevention and control of wheat soil-borne diseases in existing studies.

[0008] In order to solve the above technical deficiencies, the present invention provides a citral biopesticide for preventing and controlling wheat root and stem diseases and its application.

[0009] The experimental results of the present invention show that both citral and octanal have good antibacterial effects, among which citral has the best antibacterial effect on the three pathogens. 50 The lowest value was 31.66 mg / L. In addition, the spore production medium with a citral concentration of 0.15 mL / L completely inhibited the spore production of Fusarium graminearum and Pseudomonas graminearum, while the two pathogens could still produce less spores when the octanal concentration was 0.15 mL / L.

[0010] When the dosage of tebuconazole was halved, it had a better inhibitory effect on pathogens when mixed with citral. 50 Value, i.e. EC value of citral used in blending 25 When inhibiting Rhizoctonia graminearum, the EC value of citral 25 The value is 17.06mg / L; when inhibiting Fusarium graminearum and Pseudomonas graminearum, the EC of citral is 25 The values ​​are 37.46mg / L and 65.33mg / L respectively.

[0011] Citral microcapsules mixed with pentazole·imidacloprid for seed dressing have a significant growth-promoting effect on wheat. Compared with the pentazole·imidacloprid (3mL / kg) treatment group, the mixed seed dressing treatment group showed a significant increase in wheat root length, fresh weight, stem base width, root-crown ratio, etc. The disease prevention effect of using 3 / 4 pentazole·imidacloprid mixed with 2ml 5% citral microcapsules for seed dressing was lower than that of the conventional pentazole·imidacloprid dosage (3mL / kg); the incidence of diseases caused by three pathogens was reduced by 8.33-16.67%, achieving the purpose of reducing the use of pesticides and increasing efficiency.

[0012] The spraying of citral microcapsules and tebuconazole mixed agents further verified that the mixed agents had good control effects on wheat soil-borne fungal diseases. Among them, the control effect on wheat stem base rot caused by Fusarium graminearum was the best. The effect of tebuconazole mixed with citral microcapsules at half the dosage was better than the recommended dosage of tebuconazole (0.4mL / L). When 0.2mL / L tebuconazole + 12mL / L 5% citral was used, the incidence rate was 41.67%, and when 0.4mL / L tebuconazole was used, the incidence rate was 50.00%.

[0013] Based on the above experimental results, we provide the following technical solutions:

[0014] The invention provides a biological pesticide composition containing citral. The effective ingredients of the composition include citral and a chemical fungicide.

[0015] Preferably, the composition comprises citral and tebuconazole.

[0016] The present invention provides a biological pesticide composition containing citral, which can be used for preventing and controlling Rhizoctonia graminearum. The composition is prepared by adding different doses of citral to 0.05 mg / L of tebuconazole so that the final concentration is 6 mg / L, 11.95 mg / L, 23.85 mg / L, 35.75 mg / L, 47.65 mg / L, or within the range of corresponding proportion components.

[0017] The present invention provides a biological pesticide composition containing citral, which can be used for preventing and controlling Fusarium graminearum. The composition is prepared by adding different doses of citral to 0.09 mg / L of tebuconazole so that the final concentration is 6.04 mg / L, 29.84 mg / L, 59.59 mg / L, 89.34 mg / L, 119.09 mg / L, or within the range of corresponding proportion components.

[0018] The present invention provides a biological pesticide composition containing citral, which can be used for preventing and controlling Fusarium graminearum. The composition is prepared by adding different doses of citral to 0.2 mg / L of tebuconazole so that the final concentration is 29.95 mg / L, 59.7 mg / L, 119.2 mg / L, 178.7 mg / L, 238.2 mg / L, or within the range of corresponding proportion components.

[0019] Preferably, the composition comprises citral, penthazole and imidacloprid.

[0020] The invention provides a biological pesticide composition containing citral, which can be used for wheat seed dressing to prevent and control wheat soil-borne diseases. The composition is 3 / 4 pentazole·imidacloprid+1.5ml 5% citral microcapsule and 3 / 4 pentazole·imidacloprid+2ml 5% citral microcapsule, or within the range of corresponding proportion components.

[0021] The invention provides a biological pesticide composition containing citral, which can be used for wheat seed dressing to prevent and control wheat soil-borne diseases. The composition is 3 / 4 tebuconazole·imidacloprid+2ml 5% citral microcapsule, or within the range of corresponding proportion components.

[0022] The invention provides a biological pesticide composition containing citral, which can be applied to wheat spraying to prevent and control wheat soil-borne diseases. The composition is 0.2mL / L tebuconazole+12mL / L 5% citral microcapsules, or within the range of corresponding proportion components.

[0023] The beneficial effect of the present invention is that the present invention compares and analyzes the plant-derived volatile metabolite citral and finds that it has strong antibacterial activity against wheat soil-borne pathogenic fungi. On this basis, the screened metabolites are mixed with tebuconazole, which can effectively reduce the usage of tebuconazole, have a good control effect on the disease, and improve the safety of wheat production and the environment. The research results will provide a reference for the development of new natural fungicides for the prevention and treatment of wheat soil-borne diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 These are the antibacterial effects of citral and octanal on Rhizoctonia graminearum, where row A shows the antibacterial effect of citral and row B shows the antibacterial effect of octanal.

[0025] Figure 2 It is the antibacterial effect of citral and octanal on Fusarium graminearum, where A is the antibacterial effect of citral and B is the antibacterial effect of octanal.

[0026] Figure 3 It is the antibacterial effect of citral and octanal on Fusarium graminearum, where A is the antibacterial effect of citral and B is the antibacterial effect of octanal.

[0027] Figure 4 The effect of citral and octanal on the spore production of Fusarium graminearum.

[0028] Figure 5 The effect of citral and octanal on the spore production of Fusarium graminearum.

[0029] Figure 6 The antibacterial effect of different concentrations of tebuconazole on Rhizoctonia graminearum.

[0030] Figure 7 The antibacterial effect of different concentrations of tebuconazole on Fusarium graminearum.

[0031] Figure 8 The antibacterial effect of different concentrations of tebuconazole on Fusarium graminearum.

[0032] Fig. 9 The antibacterial effect of half-reduced tebuconazole mixed with citral on Rhizoctonia graminearum.

[0033] Fig.10 It is the antibacterial effect of adding different concentrations of citral on Fusarium graminearum when the concentration of tebuconazole is halved.

[0034] Fig.11 The antibacterial effect of adding different concentrations of citral on Fusarium graminearum when the concentration of tebuconazole is halved.

[0035] Fig.12 These are experimental photos of the growth-promoting effect of a mixture of pentazole·imidacloprid and citral microcapsules on wheat seed dressing, among which A is the growth-promoting effect of clean water treatment; B is the growth-promoting effect of pentazole·imidacloprid seed dressing; C: the growth-promoting effect of 3 / 4 pentazole·imidacloprid + 1.5ml citral microcapsules mixed with seed dressing; D is the growth-promoting effect of 3 / 4 pentazole·imidacloprid + 2ml citral microcapsules mixed with seed dressing; E is the growth-promoting effect of 3 / 4 pentazole·imidacloprid seed dressing.

[0036] Fig.13 It is the control effect of soil-borne diseases of wheat by mixing tebuconazole, imidacloprid and citral microcapsules for seed dressing.

[0037] Fig.14 It is the control effect of spraying a mixture of tebuconazole, imidacloprid and citral microcapsules on soil-borne diseases of wheat. DETAILED DESCRIPTION

[0038] This patent has conducted a series of experiments, and the experimental materials are as follows:

[0039] 1. Test strains

[0040] Test pathogens: R.cerealis, F.graminearum, F.pseudograminearum provided by our laboratory

[0041] 2. Test culture medium

[0042] PDA medium (Potato dextrose agar)

[0043] CMC medium (carboxymethylcellulose sodium salt)

[0044] 3. Test reagents

[0045] Citral, Octanal, 5% citral microcapsules, tebuconazole, imidacloprid, tebuconazole.

[0046] 4. The wheat variety used for the test was Jimai 22.

[0047] Example 1 Fumigation and antibacterial effects of citral and octanal on three pathogens

[0048] 1. Antibacterial effects of citral and octanal on Rhizoctonia graminearum

[0049] In order to compare the antibacterial effects of citral and octanal on Rhizoctonia graminearum, the fumigation antibacterial activity was determined by the growth rate method. Six concentrations (0 mg / L, 11.9 mg / L, 23.8 mg / L, 35.7 mg / L, 47.6 mg / L, and 59.5 mg / L) were set in the citral experimental group. Six concentrations (0 mg / L, 22 mg / L, 33 mg / L, 44 mg / L, 55 mg / L, and 66 mg / L) were set in the octanal experimental group. The cells were cultured at 25 °C in an incubator to compare the antibacterial effects. The results showed that as the concentration continued to increase, the inhibition rate of citral and octanal on Rhizoctonia graminearum also increased (the results are shown in Table 1). The EC value of citral on Rhizoctonia graminearum 50 The EC value of octanal against Rhizoctonia graminearum was 31.66 mg / L. 50 was 33.35 mg / L, and both showed good antibacterial effects, and the effect of citral was better than that of octanal (see the results in Figure 1 and Table 2 ).

[0050] Table 1 Antibacterial effect of citral on Rhizoctonia graminearum

[0051]

[0052] Table 2 Indoor toxicity determination of citral and octanal against Rhizoctonia graminearum

[0053]

[0054] 2. Antibacterial effects of citral and octanal on Fusarium graminearum

[0055] In order to compare the antibacterial effects of citral and octanal on Fusarium graminearum, the fumigation antibacterial activity was determined by the growth rate method. Six concentrations (0 mg / L, 29.75 mg / L, 59.5 mg / L, 89.25 mg / L, 119 mg / L, 148.75 mg / L) were set for the citral experimental group. Six concentrations (0 mg / L, 55 mg / L, 110 mg / L, 165 mg / L, 220 mg / L, 275 mg / L) were set for the octanal experimental group. The cells were cultured at 25 °C in an incubator to compare the antibacterial effects. The results showed that the EC of citral against Fusarium graminearum was 1.3447 W / m. 50 The EC value of octanal against Fusarium graminearum is 80.81 mg / L. 50 is 133.51 mg / L, and citral is better than octanal (see the results Figure 2 and Table 3, Table 4).

[0056] Table 3 Antibacterial effect of citral on Fusarium graminearum

[0057]

[0058] Table 4 Indoor toxicity test of citral and octanal against Fusarium graminearum

[0059]

[0060] 3. Antibacterial effects of citral and octanal on Fusarium graminearum

[0061] In order to compare the antibacterial effects of citral and octanal on F. graminearum, the fumigation antibacterial activity was determined by the growth rate method. Six concentrations (0 mg / L, 59.5 mg / L, 119 mg / L, 178.5 mg / L, 238 mg / L, and 297.5 mg / L) were set for the citral experimental group. Six concentrations (0 mg / L, 110 mg / L, 165 mg / L, 220 mg / L, 275 mg / L, and 330 mg / L) were set for the octanal experimental group. The cells were cultured at 25 °C in an incubator to compare the antibacterial effects. The results showed that the EC of citral against F. graminearum was 1.3447 W / m. 50 The EC value of octanal against Fusarium graminearum was 129.36 mg / L. 50 is 179.03 mg / L, and the effect of citral is better than that of octanal (see the results Figure 3 and Table 5, Table 6).

[0062] Table 5 Antibacterial effect of citral on F. graminearum

[0063]

[0064] Table 6 Indoor toxicity test of citral and octanal against Fusarium graminearum

[0065]

[0066] In summary, the antibacterial effects of citral and octanal on Rhizoctonia graminearum, Fusarium graminearum and Pseudofusarium graminearum were measured respectively. The results showed that citral had a good antibacterial effect on Rhizoctonia graminearum, Fusarium graminearum and Pseudofusarium graminearum.

[0067] Example 2 Effect of citral and octanal on the number of spores produced by pathogens

[0068] 1. Effects of citral and octanal on the spore production of Fusarium graminearum

[0069] In order to verify that citral is better than octanal, different doses of citral and octanal were added to the conidial medium with Fusarium graminearum cake to make the concentrations of 0mL / L, 0.05mL / L, 0.1mL / L, 0.15mL / L, and 0.2mL / L, respectively, and the effects of the two on the conidial production of Fusarium graminearum were analyzed. The results showed that the conidial production of Fusarium graminearum in the medium without citral and octanal was 1.8×106 In the 0.15mL / L spore-forming medium with citral, Fusarium graminearum completely lost its spore-forming ability. However, in the 0.15mL / L spore-forming medium with octanal, Fusarium graminearum was still able to produce spores (see Figure 4 and Table 7).

[0070] Table 7 Effects of different concentrations of citral and octanal on the spore production of Fusarium graminearum

[0071]

[0072] 2. Effects of citral and octanal on the spore production of Fusarium graminearum

[0073] In order to verify that citral is better than octanal, different doses of citral and octanal were added to the conidia production medium with the addition of the Pseudo-graminearum Fusarium cake to make the concentrations of 0mL / L, 0.05mL / L, 0.1mL / L, 0.15mL / L, and 0.2mL / L, and the effects of the two on the conidia production of Pseudo-graminearum Fusarium were analyzed. The results showed that the conidia production of Pseudo-graminearum Fusarium in the culture medium without the addition of citral and octanal was 1.6×10 6 In the 0.15mL / L conidia medium with citral, the spore production of Fusarium graminearum completely lost its ability to produce spores. In the 0.15mL / L conidia medium with octanal, the conidia production was reduced to 1.0×10 5 The conidial capacity of 100 / mL was significantly inhibited, and the experiment proved that citral was better than octanal (see Figure 5 and Table 8).

[0074] Table 8 Effects of different concentrations of citral and octanal on the spore production of Fusarium graminearum

[0075]

[0076] In summary, in the spore-forming medium containing 0.15 mL / L citral, Fusarium graminearum and Pseudofusarium graminearum have lost their spore-forming ability. However, in the spore-forming medium containing 0.15 mL / L octanal, Fusarium graminearum and Pseudofusarium graminearum can still produce spores. The experiment also proves that citral is better than octanal.

[0077] The test results further prove that the two metabolites, citral and octanal, can directly attack different pathogens and inhibit the spore production of pathogens and then inhibit the growth of pathogens. At the same time, conidia are the key medium for the spread and diffusion of pathogens. Controlling the formation of conidia is of great significance to the occurrence and spread of crop diseases. Therefore, it is very important to further study the control effect of the two metabolites, which also lays a good foundation for the development and utilization of natural fungicides in the future.

[0078] Example 3 Antibacterial effect of tebuconazole on three pathogenic bacteria

[0079] 1. Antibacterial effect of tebuconazole on Rhizoctonia graminearum

[0080] In order to determine the antibacterial effect of tebuconazole on Rhizoctonia graminearum, 6 tebuconazole plates with different concentrations (0 mg / L, 0.03125 mg / L, 0.0625 mg / L, 0.125 mg / L, 0.25 mg / L, and 0.5 mg / L) were prepared and inverted in a 25°C incubator. The results showed that as the concentration of tebuconazole gradually increased, the colony diameter decreased significantly. The EC value of tebuconazole on Rhizoctonia graminearum was 0.1747 W / m. 50 0.1 mg / L (see Figure 6 and Table 9).

[0081] Table 9 Indoor toxicity determination of tebuconazole against Rhizoctonia graminearum

[0082]

[0083] 2. Antibacterial effect of tebuconazole on Fusarium graminearum

[0084] In order to determine the antibacterial effect of tebuconazole on Fusarium graminearum, 6 tebuconazole plates with different concentrations (0 mg / L, 0.0625 mg / L, 0.125 mg / L, 0.25 mg / L, 0.5 mg / L, 1 mg / L) were prepared and inverted in a 25°C incubator. The results showed that as the concentration of tebuconazole gradually increased, the colony diameter decreased significantly. The EC value of tebuconazole on Fusarium graminearum was 2.34. 50 0.18 mg / L (see Figure 7 and Table 10).

[0085] Table 10 Indoor toxicity determination of tebuconazole against Fusarium graminearum

[0086]

[0087] 3. Antibacterial effect of tebuconazole on Fusarium graminearum

[0088] In order to determine the antibacterial effect of tebuconazole on F. graminearum, 6 tebuconazole plates with different concentrations (0 mg / L, 0.125 mg / L, 0.25 mg / L, 0.5 mg / L, 1 mg / L, and 2 mg / L) were prepared and inverted in a 25°C incubator. The results showed that tebuconazole had a good inhibitory effect on F. graminearum, and EC 50 0.41 mg / L (see Figure 8 and Table 11).

[0089] Table 11 Indoor toxicity determination of tebuconazole against Fusarium graminearum

[0090]

[0091] Example 4 Antibacterial effect of tebuconazole mixed with citral at half the dosage on wheat soil-borne pathogens

[0092] 1. Antibacterial effect of tebuconazole mixed with citral at half the dosage against Rhizoctonia graminearum

[0093] EC of Rhizoctonia graminearum by using tebuconazole 25 (i.e. tebuconazole 0.05 mg / L), set up 7 concentration treatments (0 mg / L, tebuconazole 0.05 mg / L, adding different doses of citral to the tebuconazole 0.05 mg / L culture dish cover to make the final concentration 6 mg / L, 11.95 mg / L, 23.85 mg / L, 35.75 mg / L, 47.65 mg / L), and inverted culture in a 25°C incubator. The results showed that the antibacterial rate was 28% at 0.05 mg / L (tebuconazole), and the antibacterial effect was significantly enhanced after adding different doses of citral. At this time, the EC mixed with citral and tebuconazole was 50 Value, i.e. EC value of citral used in blending 22 The value was 17.06 mg / L, indicating that the mixture of citral and tebuconazole can have a synergistic effect (see Fig. 9 and Table 12, Table 13).

[0094] Table 12 Antibacterial effect of tebuconazole at half dosage mixed with citral on Rhizoctonia cerealis

[0095]

[0096] Table 13 Indoor toxicity test of tebuconazole halved and citral mixed against Rhizoctonia cerealis

[0097]

[0098] 2. Antibacterial effect of tebuconazole mixed with citral at half the dosage on Fusarium graminearum

[0099] EC of Tebuconazole against Fusarium graminearum 25 (i.e. tebuconazole 0.09 mg / L), set up 7 concentration treatments (0 mg / L, tebuconazole 0.09 mg / L, adding different doses of citral to the tebuconazole 0.09 mg / L culture dish cover to make the final concentration 6.04 mg / L, 29.84 mg / L, 59.59 mg / L, 89.34 mg / L, 119.09 mg / L), and inverted culture in a 25°C incubator. The results showed that the antibacterial rate was 25% at 0.09 mg / L (tebuconazole), and the antibacterial effect was significantly enhanced after adding different doses of citral. At this time, the EC mixed with citral and tebuconazole was 50 Value, i.e. EC value of citral used in blending 25 The value is 37.46 mg / L (see Fig.10 and Table 14, Table 15).

[0100] Table 14 Antibacterial effect of tebuconazole mixed with citral at half the dosage on Fusarium graminearum

[0101]

[0102]

[0103] Table 15 Indoor toxicity test of half-tebuconazole and citral mixed with Fusarium graminearum

[0104]

[0105] 3. Antibacterial effect of tebuconazole mixed with citral at half the dosage on Fusarium graminearum

[0106] EC of Fusarium graminearum using tebuconazole 25 (i.e. tebuconazole 0.2 mg / L), set up 7 concentration treatments (0 mg / L, tebuconazole 0.2 mg / L, adding different doses of citral to the tebuconazole 0.2 mg / L culture dish cover to make the final concentration 29.95 mg / L, 59.7 mg / L, 119.2 mg / L, 178.7 mg / L, 238.2 mg / L), and inverted culture in a 25°C incubator. The results showed that the antibacterial rate was 28% at 0.2 mg / L (tebuconazole), and the antibacterial effect was significantly enhanced after adding different doses of citral. At this time, the EC of citral mixed with tebuconazole was 50 Value, i.e. EC value of citral used in blending 22 The value is 65.33 mg / L, which also shows that the mixture of citral and tebuconazole can have a synergistic effect (see Fig.11 and Table 16, Table 17).

[0107] Table 16 Antibacterial effect of tebuconazole at half dosage mixed with citral on pseudograminearum Fusarium

[0108]

[0109] Table 17 Indoor toxicity test of half-tebuconazole mixed with citral against Fusarium graminearum

[0110]

[0111] Example 5 Biocontrol Effect of Mixing Tebuconazole and Imidacloprid with Citral Microcapsules in Seed Dressing

[0112] 1. Evaluation of the growth-promoting effect of seed dressing with a mixture of tebuconazole, imidacloprid and citral microcapsules

[0113] At present, citral has not been applied to wheat diseases, so determining the effect of mixed seed dressing on wheat plant growth is crucial for the subsequent evaluation of disease prevention effects.

[0114] The test showed that the plant height of wheat treated with mixed seed dressing was second only to that of the control group, and the root length, fresh weight, stem base width and root-to-crown ratio of wheat treated with mixed seed dressing were higher than those of other treatment groups. There were slight differences in root length, stem base width and root-to-crown ratio between the mixed seed dressing treatment groups; there were no significant differences in plant height and fresh weight. Overall, the growth promotion effect of the 3 / 4 pentazole·imidacloprid+2ml 5% citral microcapsule treatment group was better (see the results). Fig.12 and Table 18).

[0115] Table 18 Effect of seed dressing with mixture of pentazole, imidacloprid and citral microcapsules on wheat growth

[0116]

[0117] *The same letters in each column indicate that the difference is not significant (P>0.05), and different letters indicate that the difference is significant (P<0.05).

[0118] 2. The effect of seed dressing with a mixture of tebuconazole, imidacloprid and citral microcapsules on the prevention of two soil-borne wheat diseases

[0119] A pot experiment was conducted to observe the disease prevention effect of mixed seed dressing on wheat soil-borne diseases. The wheat was taken out of the soil and washed 2-3 times with clean water, taking care not to damage the lesion morphology. The incidence of wheat was counted and the disease index of wheat was calculated. The pot experiment showed that all treatment groups could prevent and control wheat diseases compared with the control group, and the mixed seed dressing treatment group had a better effect. The two mixed treatment groups were better than the tebuconazole·imidacloprid treatment group in preventing and controlling wheat sheath blight and wheat stem base rot.

[0120] In the prevention and control of wheat sheath blight caused by Rhizoctonia graminearum, the incidence of the two mixed treatment groups was reduced by 2.78% and 8.33% respectively, and the disease index was reduced by 1.85 and 5.09 compared with the group treated with pentoconazole and imidacloprid (3ml / kg). In the prevention and control of wheat sheath blight caused by Rhizoctonia graminearum, the incidence of the two mixed treatment groups was reduced by 8.84% and 15.78% respectively, and the disease index was reduced by 9.26 and 13.89 compared with the group treated with pentoconazole and imidacloprid (3ml / kg). In the prevention and control of wheat sheath blight caused by Rhizoctonia graminearum, the incidence of the two mixed treatment groups was reduced by 13.89% and 16.67% respectively, and the disease index was reduced by 9.26 and 12.96 compared with the group treated with pentoconazole and imidacloprid (3ml / kg). Overall, 3 / 4 pentoconazole and imidacloprid + 2ml 5% citral microcapsules have a better disease prevention effect (see the results). Fig.13 and Table 19).

[0121] By reducing the dosage of penthazole·imidacloprid by 1 / 4 and mixing it with citral microcapsules, it was found that the control effect after mixing was better than the standard dosage of penthazole·imidacloprid. Therefore, the optimal ratio of citral microcapsules and penthazole·imidacloprid when applied in the field can be explored to effectively control wheat soil-borne diseases, which will be particularly important for citral to control plant diseases.

[0122] Table 19 Effect of mixed seed dressing on the prevention of soil-borne diseases of wheat

[0123]

[0124] 3.6 Control effect of spraying a mixture of tebuconazole and citral microcapsules on two soil-borne wheat diseases

[0125] The pot experiment was used to determine the disease prevention effect of citral and tebuconazole microcapsules spray on wheat soil-borne diseases. The wheat was taken out of the pot and the wheat root system was rinsed with clean water. Be careful not to damage the lesion morphology. The incidence rate and disease index of wheat were counted and calculated. As shown in Table 20, the treatment group can inhibit the disease compared with the control group. The mixed spray has the best disease prevention effect on wheat scab, with an incidence rate of 41.67% and a significant reduction in lesions (see the results). Fig.14 ), the disease index was 30.86, which was better than 0.4mL / L tebuconazole. In addition, the disease prevention effect of the mixed agent for wheat sheath blight and wheat stem base rot was second only to 0.4mL / L tebuconazole, and the difference in incidence was less than 10%. After applying 0.2mL / L tebuconazole + 12mL / L 5% citral microcapsules, the incidence of wheat sheath blight dropped from 72.22% to 37.97%, and the disease index dropped from 37.35 to 20.52; the incidence of wheat stem base rot dropped from 79.63% to 49.07%, and the disease index dropped from 56.17 to 28.70.

[0126] Table 20 Disease prevention effect of mixed spray on wheat diseases

[0127]

[0128]

[0129] The above is only a preferred implementation of this patent. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of this patent. These improvements and substitutions should also be regarded as the scope of protection of this patent.

Claims

1. A citral biopesticide for preventing and treating wheat root and stem diseases, characterized in that: The active ingredient of the pesticide is citral.

2. A citral biopesticide composition for preventing and treating wheat root and stem diseases, characterized in that: The effective ingredients of the composition include citral and chemical fungicide.

3. The composition according to claim 2, characterized in that: The composition includes citral and tebuconazole.

4. The use of the composition according to claim 3, characterized in that: The composition is used for preventing and controlling Rhizoctonia graminearum, and the composition is prepared by adding different dosages of citral to 0.05 mg / L of tebuconazole to make the final concentration be 6 mg / L, 11.95 mg / L, 23.85 mg / L, 35.75 mg / L, 47.65 mg / L, or within the range of corresponding proportion components.

5. The use of the composition according to claim 3, characterized in that: The composition is used for preventing and controlling Fusarium graminearum, and the composition is prepared by adding different dosages of citral to 0.09 mg / L of tebuconazole to make the final concentration be 6.04 mg / L, 29.84 mg / L, 59.59 mg / L, 89.34 mg / L, 119.09 mg / L, or within the range of corresponding proportion components.

6. The use of the composition according to claim 2, characterized in that: The composition is used for preventing and controlling Fusarium graminearum, and the composition is prepared by adding different dosages of citral to 0.2 mg / L of tebuconazole to make the final concentration be 29.95 mg / L, 59.7 mg / L, 119.2 mg / L, 178.7 mg / L, 238.2 mg / L, or within the range of corresponding proportion components.

7. The composition according to claim 3, characterized in that: The composition comprises citral, penthazole and imidacloprid.

8. The use of the composition according to claim 7, characterized in that: The composition is used for wheat seed dressing to prevent and control wheat soil-borne diseases. The composition is 3 / 4 pentazole·imidacloprid+1.5ml 5% citral microcapsule and 3 / 4 pentazole·imidacloprid+2ml 5% citral microcapsule, or within the range of corresponding proportion components.

9. The use of the composition according to claim 8, characterized in that: The composition is applied to wheat seed dressing for preventing and controlling wheat soil-borne diseases, and the composition is 3 / 4 tebuconazole·imidacloprid+2 ml 5% citral microcapsules, or within the range of corresponding proportion components.

10. 根据权利要求3所述组合物的应用 ， 其特征在于 ： 所述组合物应用于小麦喷雾防治小麦土传病 The composition is 0.2 mL / L tebuconazole + 12 mL / L 5% citral microcapsules, or within the range of corresponding proportions.

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