CN111543439A

CN111543439A - Agricultural bactericidal composition

Info

Publication number: CN111543439A
Application number: CN202010423726.1A
Authority: CN
Inventors: 张文娟
Original assignee: Weinan Vocational & Technical College
Current assignee: Weinan Vocational & Technical College
Priority date: 2020-05-19
Filing date: 2020-05-19
Publication date: 2020-08-18

Abstract

The invention discloses an agricultural sterilization composition, wherein the sterilization component comprises a Streptomyces parvus fermentation broth dried product and one of pyraclostrobin and isopyrazam; the mass ratio of the Streptomyces parvus fermentation broth dried product to the pyraclostrobin is 10: 1-1: 15; the mass ratio of the Streptomyces parvus fermentation broth dried product to the isopyrazam is 40: 1-1: 10. The invention has reasonable component compounding and good sterilization effect, and the activity and the sterilization effect are not simple superposition of the activities of the components, compared with the prior single preparation, the invention has obvious sterilization effect, obvious synergistic effect and good safety to crops. The invention has better control effect on banana leaf spot, cucumber powdery mildew, citrus anthracnose and strawberry powdery mildew.

Description

Agricultural bactericidal composition

Technical Field

The invention belongs to the technical field of compound pesticides, and relates to a sterilization composition which comprises a sterilization component of a compound of Streptomyces parvus fermentation liquor and pyraclostrobin or isopyrazam. The invention also discloses application of the bactericidal composition in the field of agriculture.

Background

With the development of agricultural economy, pesticides increasingly become indispensable production data in agricultural production, and play an extremely important role in the aspects of stable yield, high yield, product quality and the like of crops such as grains and the like. On the other hand, the use of agricultural chemicals is related to the safety problem of agricultural products, especially the problem of pesticide residue, not only relates to the health of people, but also becomes an important obstacle for export of agricultural products in China. With the improvement of environmental awareness of people and the continuous deepening of human sustainable development, the active development, popularization and application of biopesticides become global consensus.

In recent years, companies such as Zhangda, DuPont and Bayer in pesticide enterprises are involved in the field of biopesticides, so that the development trend of biopesticides is raised again. The structure of the pesticide product in China still mainly comprises chemical pesticides at present, and according to statistics, the market share of the pesticide product accounts for more than 90% of all pesticides, while the market share of biological pesticides is less than 10%. In the development and utilization aspects of biological pesticides, China has a plurality of biological pesticides in turn to be put into production and application, such as blasticidin, kasugamycin, validamycin, gibberellin, polyoxin, abamectin, pesticide 120, zhongshengmycin, ningnanmycin and the like, and the biological pesticides make great contribution to grain production and grain safety in China. From the macroscopic view, China is a big country for applying biological pesticides, but the varieties and the quantity of the biological pesticides are limited, the market share is not high, and the difference with the requirements of green prevention and control and green food production in China exists. So far, China has no really original biopesticide varieties, which is quite different from the status of the big countries in China. Therefore, actively screening and developing new high-efficiency and low-toxicity biopesticide varieties has very important significance for agricultural production in China and improvement of international status in China.

The natural product has rich structure and chemical diversity and is an ideal resource for developing pesticides. The microbial source biopesticide does not harm human and livestock, has no soil residue, does not pollute the environment, does not kill natural enemies, is beneficial to ecological balance and stability, and is popular with people. Agricultural antibiotics, which are important components of microbial sources, have been increasingly regarded as important by people due to their incomparable superiority to synthetic pesticides. China is a big country for researching and applying agricultural antibiotics. The registered agricultural antibiotics reach more than twenty varieties, wherein the agricultural antibiotics comprise validamycin, gibberellin, abamectin, zhongshengmycin and pyrimidine nucleoside antibiotics (agricultural antibiotics, ningnanmycin and the like are main varieties for production and application, the annual output value of the agricultural antibiotics reaches more than 20 hundred million yuan, which accounts for 90 percent of biological pesticides. the research on the aspect of the antibiotics abroad is characterized in that the research on the antibiotics mainly used for medical purposes, such as antibiosis, antitumor, antivirus, immunosuppressant and the like is more extensive, the research on the agricultural antibiotics is relatively less, the research also provides a good opportunity for developing new agricultural antibiotics, along with the wide use of the traditional antibiotics, the drug resistance of bacteria is rapidly increased, and the obvious decline trend appears when active compounds with novel structures are found from the traditional soil microorganisms, on the other hand, the unique advantages of natural products determine that the research on the natural products of the microorganisms cannot be replaced by the result of chemical synthesis research, the future development direction of natural microbial products is increasingly attracting people's attention and cannot be avoided.

Disclosure of Invention

Streptomyces Parvus is an actinomycete strain that is screened from contaminated environmental soils and metabolizes agriculturally active substances, and information on the isolation and identification of Streptomyces Parvus is found in the papers published by the inventors (antibiotic Activity and Composition of the Fermentation Broth of Streptomyces Parvus 33, Jundhaphur J Microbiol.2017 Autogust; 10 (8): e 12677). The inventor takes part of crop pathogenic fungi and pathogenic bacteria as research objects and evaluates the indoor living body bacteriostatic activity of Streptomyces parvus fermentation liquor. At present, agricultural application related to Streptomyces parvus still stays in a test research stage, and is not used for preventing and controlling field crop diseases, and in order to promote popularization and implementation of related research achievements of Streptomyces parvus in the field of agriculture and forestry, the invention combines test verification data in the previous stage to compound Streptomyces parvus fermentation liquor and the existing sterilization components (pyraclostrobin or isopyrazam) to provide the agricultural sterilization composition.

In order to achieve the purpose, the invention adopts the following technical scheme: an agricultural sterilization composition comprises a sterilization component and a sterilization component, wherein the sterilization component comprises a Streptomyces parvus fermentation broth dried product and one of pyraclostrobin and isopyrazam;

the mass ratio of the Streptomyces parvus fermentation broth dried product to the pyraclostrobin is 10: 1-1: 15;

the mass ratio of the Streptomyces parvus fermentation broth dried product to the isopyrazam is 40: 1-1: 10.

The Streptomyces parvus fermentation liquor dried substance and the pyraclostrobin are compounded and combined for use, the synergistic effect is shown in the range of the mass ratio of the Streptomyces parvus fermentation liquor dried substance to the pyraclostrobin being 35: 1-1: 15, and the control effect on plant diseases is enhanced.

Pyraclostrobin belongs to strobilurin bactericides and mainly acts on cytochrome bel compounds in mitochondrial respiratory chains of fungi to prevent electron transfer so as to inhibit the growth of the fungi. As one of the important strobilurin bactericides, since the strobilurin bactericides are put on the market, the strobilurin bactericide has a wide bactericidal spectrum and a large number of target germs, and has excellent effects on the aspects of improving the stress resistance of crops, promoting the growth of the crops, resisting aging, enhancing immunity and the like. The defects of the pyraclostrobin in the field are mainly shown as follows: firstly, the bactericidal action significant time of the pyraclostrobin is between that of a protective agent and that of a therapeutic agent, and the using time of the pyraclostrobin needs to be reasonably determined; secondly, the local concentration of the liquid medicine is too high along with the evaporation of water to cause burnt medicine spots and reduce the quality of crop products. According to the invention, the scheme of compounding the Streptomyces parvus fermentation broth dry product and the pyraclostrobin is adopted, and the using concentration and the using amount of the pyraclostrobin are reduced and the risk of using a single dose of the pyraclostrobin to cause harm is reduced or weakened through the synergistic effect of microbial fermentation products.

The isopyrazam is an important SDHI bactericide containing pyrazole rings which is developed by pioneer. The SDHIs bactericide acts through a protein complex II (i.e., succinate dehydrogenase or succinate-ubiquinone reductase) on the mitochondrial respiratory electron transport chain of pathogenic bacteria. With the introduction of more SDHIs bactericides and the expansion of the range of applications, resistance problems of SDHIs bactericides have been reported successively around the world. At present, many pathogenic bacteria generating resistance to SDHIs bactericides are found in field crop plants, and the pathogenic bacteria with higher risk mainly comprise botrytis cinerea, alternaria alternata, fusarium oxysporum, corynespora polystachya, powdery mildew and the like. The bactericide with different action mechanisms is compounded with the isopyrazam, so that the resistance problem of the product can be delayed, and the market share of the product in the later patent period can be maintained. In order to search for a new application way or a new application mode of the isopyrazam, the invention compounds the dried product of the Streptomyces parvus fermentation liquor with the isopyrazam.

The invention provides a preferable fermentation method of Streptomyces parvus, which comprises the following steps: inoculating Streptomyces parvus into seed culture medium (modified Gaoshi No. 1, purchased from Hippobo Biotechnology Co., Ltd., Hippocampus, Hi; inoculating fermentation strain into 50L fermentation tank containing fermentation culture medium, stirring, and setting fermentation conditions for fermentation production. Setting fermentation parameters: the liquid loading amount is 20L/50L, the initial pH value is 7.5, the rotating speed is 130rpm, the fermentation temperature is 28 ℃, and the fermentation time is 5 d. The fermentation medium comprises the following components: 5g of soluble corn starch, 2g of corn steep liquor, 4g of peptone, 1g of soluble cellulose, 5g of glucose, 0.5g of dipotassium hydrogen phosphate, 3g of calcium carbonate, 0.5g of sodium chloride and 0.5g of magnesium sulfate.

The dried product of the Streptomyces parvus fermentation liquor is a powder prepared by taking the fermentation liquor of actinomycetes Streptomyces parvus as a raw material and adopting a spray drying mode. Filtering to remove the Streptomyces parvus thallus, and spray drying the obtained sterile filtrate to obtain the dried Streptomyces parvus fermentation liquor. Setting spray drying parameters: the inlet air temperature is 115 ℃, and the feeding amount is 6%.

In another aspect, the invention discusses the application of the agricultural bactericidal composition in preventing and treating crop diseases.

Specifically, the crop diseases which can be controlled by applying the agricultural bactericidal composition comprise sigatoka, cucumber powdery mildew, citrus anthracnose and strawberry powdery mildew.

Specifically, when the agricultural bactericidal composition is applied, the agricultural bactericidal composition is prepared into a preparation convenient for preventing and treating crop diseases.

Regarding the formulation form of the agricultural bactericidal composition, preferably, the formulation which can be formulated according to the method known to those skilled in the art may be a suspension, a water dispersible granule, a wettable powder, a dispersible oil suspension or an aqueous emulsion. In the preparation of the above formulation, different auxiliary components (adjuvants) of the pesticide preparation can be selected and used as required. The auxiliary components are one or more of a dispersing medium, a dispersing agent, an emulsifying agent, a wetting agent, a thickening agent, a defoaming agent, an antifreezing agent, a disintegrating agent, a binder and a filler.

For the suspending agents, usable are: dispersants such as one or more of polycarboxylate, lignosulfonate, alkylnaphthalene sulfonate (dispersant NNO), TERSPERSE2020 (alkyl naphthalene sulfonate, available from henseme, usa); emulsifier such as one or more of Nongru 700# (common name: alkylphenol formaldehyde resin polyoxyethylene ether), Nongru 2201, span-60 # (common name: sorbitan stearate), Tween-60 # (common name: polyoxyethylene sorbitan stearate), Nongru 1601# (common name: triphenylethylphenol polyoxypropylene polyoxyethylene block polymer), TERSPERSE 4894 (Hensmei company, USA); wetting agents such as one or more of alkyl phenol polyoxyethylene ether formaldehyde condensate sulfate, alkyl phenol polyoxyethylene ether phosphate, phenethyl phenol polyoxyethylene ether phosphate, alkyl sulfate, alkyl sulfonate, naphthalene sulfonate, TERSPERSE 2500 (available from henseme, usa); thickening agent such as one or more of xanthan gum, polyvinyl alcohol, bentonite, and magnesium aluminum silicate; preservatives such as one or more of formaldehyde, benzoic acid, sodium benzoate; stabilizer such as one or more of epoxidized soybean oil, epichlorohydrin, and triphenyl phosphate; defoaming agents such as silicone-based defoaming agents; antifreeze agents such as one or more of ethylene glycol, propylene glycol, glycerol, urea, inorganic salts such as sodium chloride; the water is deionized water.

For water dispersible granules, the person skilled in the art is familiar with the use of corresponding auxiliaries for carrying out the invention. Dispersants such as one or more of polycarboxylates (TERSPERSE 2700, T36, GY-D06, etc.), lignosulfonates, alkylnaphthalene sulfonates; wetting agents such as one or more of alkyl sulfate, alkyl sulfonate, naphthalene sulfonate; disintegrating agent such as one or more of ammonium sulfate, sodium sulfate, polyvinylpyrrolidone, starch and its derivatives, and bentonite; binder such as one or more of starch, glucose, polyvinyl alcohol, polyethylene glycol, sodium carboxymethylcellulose, and sucrose; the filler is one or more of diatomite, kaolin, white carbon black, light calcium carbonate, talcum powder, attapulgite and pottery clay.

For wettable powders, the auxiliaries which can be used are: dispersants such as one or more of polycarboxylates (TERSPERSE 2700, T36, GY-D06, etc.), lignosulfonates (Ufoxane 3A, Bordetese NA, Bordetese CA-SA, etc.), naphthalene and alkylnaphthalene formaldehyde condensate sulfonates (NNO, MF, Morwet D-425, Tamol NN, TERSPERSE2020, etc.), nekal BX (sodium dibutylnaphthalene sulfonate), EO-PO block polyethers, alkylphenol polyoxyethylene ether phosphates, alkylphenol polyoxyethylene ether formaldehyde condensate Sulfates (SOPA); wetting agents such as one or more of sulfates (K-12), sulfonates (ABS-Na, BX, Terwet 1004, etc.), composite wetting agents (Morwet EFW); the filler is one or more of diatomite, kaolin, light calcium carbonate, talcum powder, white carbon black, attapulgite, argil, ammonium sulfate, urea, sucrose, glucose, corn starch, sodium sulfate, sodium polyphosphate and the like.

For dispersible oil suspensions, the adjuvants that can be used are: dispersing agent such as one or more of polycarboxylate, lignosulfonate, alkylnaphthalene sulfonate (dispersant NNO), TERSPERSE2020 (product of Huntsman corporation, U.S. alkyl naphthalene sulfonate); the emulsifier is selected from BY (polyoxyethylene castor oil) series emulsifier (BY-110, BY-125, BY-140), agricultural milk 700# (common name: alkylphenol formaldehyde resin polyoxyethylene ether), agricultural milk 2201, span-60 # (common name: sorbitan monostearate), Tween-60 # (common name: sorbitan monostearate polyoxyethylene ether), agricultural milk 1601# (common name: phenethylphenol polyoxyethylene polyoxypropylene ether), and TERSPERSE 4894 (produced BY Henshimei corporation, USA); wetting agents such as one or more of alkylphenol polyoxyethylene ether formaldehyde condensate sulfate, alkylphenol polyoxyethylene ether phosphate, phenethylphenol polyoxyethylene ether phosphate, alkyl sulfate, alkyl sulfonate, naphthalene sulfonate, TERSPERSE 2500 (available from henseme, usa); thickening agent such as one or more of white carbon black, polyvinyl alcohol, bentonite, and magnesium aluminum silicate; antifreeze agents such as one or more of ethylene glycol, propylene glycol, glycerol, urea, inorganic salts such as sodium chloride; dispersing medium such as one or more of soybean oil, oleum Rapae, oleum Maydis, methyl oleate, diesel oil, engine oil, and mineral oil.

For aqueous emulsions, the auxiliaries which can be used are: emulsifying agents such as nonylphenol polyoxyethylene (EO 10) ether phosphate, tristyrylphenol polyoxyethylene ether phosphate, Nongru No. 700 (common name: alkylphenol formaldehyde resin polyoxyethylene ether), Nongru No. 2201, span-60 (common name: sorbitan stearate), Tween-60 (common name: polyoxyethylene sorbitan stearate), TX-10 (common name: octylphenol polyoxyethylene (10) ether), Nongru 1601 (common name: tristyrylphenol polyoxypropylene polyoxyethylene block polymer), Nongru No. 600, Nongru No. 400; solvent such as one or more of xylene, toluene, cyclohexanone, solvent oil (trade name: S-150, S-180, S-200); one or more stabilizers such as triphenyl phosphite, epichlorohydrin and epoxidized soybean oil; an antifreezing agent: one or more of ethylene glycol, propylene glycol, glycerol, urea, and inorganic salts such as sodium chloride; thickening agent such as one or more of xanthan gum, polyvinyl alcohol, bentonite, and magnesium aluminum silicate; the antiseptic is one or more of formaldehyde, benzoic acid, and sodium benzoate, and the water is deionized water.

The agricultural bactericidal composition has the advantages or beneficial effects that:

the agricultural bactericidal composition comprises a first active ingredient Streptomyces parvus fermentation liquor dried product and a second active ingredient which is one of pyraclostrobin and isopyrazam. The mass ratio of the Streptomyces parvus fermentation broth dry product to the pyraclostrobin is 10: 1-1: 15, and the Streptomyces parvus fermentation broth dry product and the pyraclostrobin show a synergistic effect; the mass ratio of the Streptomyces parvus fermentation broth dry product to the isopyrazam is 40: 1-1: 10, and the Streptomyces parvus fermentation broth dry product and the isopyrazam show a synergistic effect. The invention innovatively explores the application of the Streptomyces parvus fermentation broth dry product in plant disease control, is combined with one of pyraclostrobin and isopyrazam for use, and can be well used for controlling diseases such as banana leaf spot, cucumber powdery mildew, citrus anthracnose, strawberry powdery mildew and the like. In addition, the bactericidal composition has the advantages of reasonable components, treatment and protection effects, good bactericidal effect, low medication cost, good safety to crops and accordance with the safety requirement of pesticide preparations.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the embodiments described herein are merely illustrative of the present invention and are not intended to limit the invention, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Example 1

This example uses mycelium dry weight measurements to determine the combined virulence of Streptomyces parvus fermentation broth dry matter (denoted as SP) in combination with one of pyraclostrobin (denoted as PSN) and isopyrazam (denoted as IZM) against A. bananas.

Preparing the medicament into high-concentration mother liquor, diluting the mother liquor into liquid medicines with series concentrations, adding the liquid medicines into a quantitative liquid culture medium according to different dosages to prepare a liquid culture medium with the medicament, and repeating the concentration treatment for 4 times. Quantitatively sucking liquid culture solution containing mycelium from a sterile pipette, injecting into liquid culture medium containing medicine, and setting blank control. Culturing at 28 deg.C under constant temperature shaking condition for 10 days, filtering mycelium with filter paper, drying in electrothermal constant temperature air blast drying oven at 85 deg.C, weighing mycelium dry weight with electronic balance, and comparing with blank control to calculate antibacterial effect of each treatment on mycelium growth. EC calculation Using SPSS software₅₀And the correlation coefficient (SR), the results are shown in tables 1 and 2.

TABLE 1 indoor toxicity of SP and PSN combinations against Musa paradisiaca

TABLE 2 indoor virulence of SP and IZM combinations against sigatoka bacteria

Treatment agent	The actual measurement of EC50(mg/L)	Theoretical EC50(mg/L)	SR
				SP	53.33
IZM	9.53
				SP60:IZM1	44.27	50.47	1.14
SP50:IZM1	36.20	49.59	1.37
				SP40:IZM1	31.14	47.95	1.54
SP30:IZM1	28.67	46.44	1.62
				SP20:IZM1	26.04	43.75	1.68
SP10:IZM1	21.62	37.61	1.74
				SP5:IZM1	17.06	30.20	1.77
SP1:IZM1	8.88	16.17	1.82
				SP1:IZM2	6.20	11.04	1.78
SP1:IZM4	6.02	10.30	1.71
				SP1:IZM6	5.94	9.92	1.67
SP1:IZM8	6.04	9.79	1.62
				SP1:IZM10	6.19	9.72	1.57
SP1:IZM15	6.69	9.63	1.44
				SP1:IZM30	7.33	9.61	1.31

From the measurement results in the table 1, the Streptomyces parvus fermentation broth dried product and the pyraclostrobin are combined at the mass ratio of 10: 1-1: 15, and the synergy effect is shown on the sigatoka bacteria; in the mass ratio of 1:1 to 1:10, the correlation coefficient (SR) is over 1.7 and reaches 1.77 at the maximum (SP1: PSN 5). From the measurement results shown in Table 2, the Streptomyces parvus fermentation broth dry product and the isopyrazam are combined at a mass ratio of 40:1 to 1:10, so that the synergy effect on the alternaria leaf spot bacteria is shown; in the mass ratio of 10:1 to 1: 4, the correlation coefficient (SR) is over 1.7 and reaches 1.82 at the maximum (SP1: IZM 1).

Example 2

This example determines the combined virulence of Streptomyces parvus broth dry (denoted SP) in combination with one of pyraclostrobin (denoted PSN) and isopyrazam (denoted IZM) against powdery mildew of cucumber.

The test method refers to part 11 of agricultural chemical indoor bioassay test standard bactericide of the national people's republic of China, part 11 of test potting method for preventing and treating powdery mildew of cucurbits, the test object is cucumber powdery mildew sphaerotheca fuliginea, the test object is cucumber seedlings with susceptibility to powdery mildew, the potting culture is carried out until 2-4 true leaf stages, pure water with a small amount of surfactant (Tween 80) is used for washing fresh spores on full-grown cucumber leaves with powdery mildew, and double-layer gauze is used for filtering to prepare the cucumber seedlings with the spore concentration of 1 × 10⁵One spore/ml of suspension ready for use.

The preparation is prepared into the required treatment preparation, and 5 different concentration gradients (the control effect is set according to the geometric progression in the range of 5-90%) are set for a single preparation and each mixed preparation at first. Each treatment was repeated 4 times for 3 pots, and a blank was set for treatments containing only solvent and surfactant but no active ingredient. Inoculating spore suspension 24h before treating with the agent, uniformly spraying the liquid medicine on the leaf surface until the liquid medicine is completely wetted, and naturally drying the liquid medicine for later use. The potted cucumber after inoculation and medicament treatment is naturally dried, then is moved to a thermostatic chamber and is cultured for 7 to 10 days at the temperature of 20 to 24 ℃. When the blank control diseased leaf rate reaches more than 80%, investigating the diseased situation of each treatment in a grading way, investigating at least 30 leaves in each treatment, wherein the grading standard is as follows:

level 0: no disease;

level 1: the area of the lesion spots accounts for less than 5% of the area of the whole leaf;

and 3, level: the area of the lesion spots accounts for 6 to 15 percent of the area of the whole leaf;

and 5, stage: the area of the lesion spots accounts for 16 to 25 percent of the area of the whole leaf;

and 7, stage: the area of the lesion spots accounts for 26 to 50 percent of the area of the whole leaf;

and 9, stage: the area of the lesion spots accounts for 50 to 75 percent of the area of the whole leaf;

stage 11: the area of the lesion spots accounts for more than 75 percent of the area of the whole leaf.

Calculating the formula:

disease index [ ∑ (number of diseased leaves at each stage × relative stage value)/(total investigated leaf number × 11) ] × 100;

control effect (%) [ (control disease index-treatment disease index)/control disease index ] × 100.

The synergistic coefficient (SR) of each composition was determined by the Wadley method, and the results are shown in tables 3 and 4.

TABLE 3 indoor toxicity of SP and PSN combinations against cucumber powdery mildew

Treatment agent	Measured EC₅₀(mg/L)	Theoretical EC₅₀(mg/L)	SR
				SP	41.24	--	--
PSN	18.65	--	--
				SP40:PSN1	31.11	40.75	1.31
SP20:PSN1	28.22	40.63	1.44
				SP15:PSN1	27.40	40.55	1.48
SP12:PSN1	26.43	39.38	1.49
				SP10:PSN1	25.99	40.28	1.55
SP8:PSN1	25.19	40.06	1.59
				SP5:PSN1	24.35	39.69	1.63
SP2:PSN1	22.80	38.99	1.71
				SP1:PSN1	21.35	37.15	1.74
SP1:PSN2	19.28	34.31	1.78
				SP1:PSN5	11.02	18.85	1.71
SP1:PSN10	11.14	18.82	1.69
				SP1:PSN12	11.39	18.80	1.65
SP1:PSN15	11.88	18.78	1.58
				SP1:PSN20	12.67	18.75	1.48
SP1:PSN30	13.02	17.84	1.37

TABLE 4 indoor toxicity of SP and IZM combinations against cucumber powdery mildew

From the measurement results in table 3, it is known that the Streptomyces parvus fermentation broth dried product and pyraclostrobin are used in combination at a mass ratio of 10:1 to 1:15, and the synergy effect on the alternaria leaf spot bacteria is shown. From the measurement results shown in table 4, it was found that the Streptomyces parvus fermentation broth dried product and isopyrazam were used in combination at a mass ratio of 40:1 to 1:10, and showed a synergistic effect on alternaria leaf spot.

Example 3

This example determines the combined virulence of Streptomyces parvus broth dry (denoted SP) in combination with one of pyraclostrobin (denoted PSN) and isopyrazam (denoted IZM) against C.citricola.

Diluting each treatment agent into a drug-containing PDA plate with the concentration of 1 mug/mL by adopting a plate hypha growth inhibition method of NY/T1156.6-2006, respectively, cutting a bacterial cake from the edge of a bacterial colony by using a sterilization puncher with the diameter of 5mm under the aseptic operation condition, inoculating the bacterial cake to the center of the drug-containing PDA plate by using an inoculator, covering a dish cover with the hypha facing upwards, culturing at a constant temperature of 24 ℃ for 48 hours, measuring the diameter of the bacterial colony by using a caliper with the unit of mm, vertically measuring the diameter of each bacterial colony by using a cross method once, and taking the average value. The synergistic coefficient (SR) of each composition was determined by the Wadley method, and the results are shown in tables 5 and 6.

Calculation of hypha growth inhibition rate: inhibition (%) [ (blank hypha diameter-drug-treated hypha diameter)/blank hypha diameter ] × 100

TABLE 5 indoor toxicity of SP and PSN combinations against Colletotrichum citrinum

TABLE 6 indoor toxicity of SP and IZM combinations against Colletotrichum citrinum

Treatment agent	The actual measurement of EC50(mg/L)	Theoretical EC50(mg/L)	SR
				SP	30.64	--	--
IZM	5.89	--	--
				SP60:IZM1	20.66	29.13	1.41
SP50:IZM1	19.68	28.93	1.47
				SP40:IZM1	18.86	28.67	1.52
SP30:IZM1	18.15	28.31	1.56
				SP20:IZM1	17.48	27.79	1.59
SP10:IZM1	16.55	26.98	1.63
				SP5:IZM1	13.12	22.17	1.69
SP1:IZM1	11.25	18.90	1.68
				SP1:IZM2	3.61	5.98	1.66
SP1:IZM4	3.75	5.97	1.59
				SP1:IZM6	3.84	5.96	1.55
SP1:IZM8	3.94	5.95	1.51
				SP1:IZM10	3.92	5.88	1.50
SP1:IZM15	4.12	5.94	1.44

From the measurement results in table 5, it is known that the Streptomyces parvus fermentation broth dried product and pyraclostrobin are used in combination at a mass ratio of 10:1 to 1:15, and the synergy effect on the alternaria leaf spot bacteria is shown. From the measurement results shown in Table 6, it was found that the Streptomyces parvus fermentation broth dried product and the isopyrazam were used in combination at a mass ratio of 40:1 to 1:10, and showed a synergistic effect on Phyllostachys zearaldii.

Example 4

This example determines the field efficacy of Streptomyces parvus broth dry (denoted as SP) in combination with one of pyraclostrobin (denoted as PSN) and isopyrazam (denoted as IZM) on sigatoka.

The test was carried out in banana plantago leaf spot of Guangxi Wuming county, where the incidence of banana leaf spot is severe throughout the year. The test method refers to the GB/T17980.95-2004 pesticide field efficacy test rule (II) fungicide efficacy test for preventing and treating sigatoka. The test agents and the amounts are detailed in table 7. Blank control was also set, and each treatment was repeated 4 times, with 10 bananas per plot, for a total of 48 plots, and arranged in random blocks. The whole plant is uniformly sprayed by adopting a conventional spraying method. The application for the 1 st time is carried out at the initial stage of the banana leaf spot disease, and the application for the second time is carried out 14 days later, and the application is carried out for 2 times in total.

The investigation and statistical method comprises the following steps: the incidence of leaf development was investigated 14 days after the first dose and 14 days after the second dose. Randomly surveying 3 plants in each cell, surveying 8-13 leaves (not opening heart leaves but counting) from top leaves to bottom leaves of each banana, and recording the total leaf number and the leaf number of each stage of disease of the survey.

The grading method comprises the following steps:

level 0: no disease spots;

level 1: the lesion area accounts for less than 5% of the whole leaf area;

and 3, level: the lesion area accounts for 6 to 15 percent of the whole leaf area;

and 5, stage: the lesion area accounts for 16 to 25 percent of the whole leaf area;

and 7, stage: the lesion area accounts for 26-50% of the whole leaf area;

and 9, stage: the lesion area accounts for more than 50% of the whole leaf area.

The control effect is calculated according to the disease index, and the test result is shown in table 7. The influence on the growth, leaf color, flowers and fruits of bananas after application of the pesticide is observed visually after each pesticide application, and the safety of the pesticide on banana plants is examined.

Disease index [ Σ (each stage of diseased leaf number × relative stage number)/(total investigated leaf number × 9) ] × 100

Control effect (%) [ (control disease index-treatment disease index)/control disease index ] × 100

TABLE 7 field control of sigatoka

The results in table 7 show that compared with the single agents of the Streptomyces parvus fermentation broth dry product, the pyraclostrobin and the isopyrazam, the combined preparation (WP) of the Streptomyces parvus fermentation broth dry product, the pyraclostrobin and the isopyrazam obviously improves the field pesticide effect on the banana leaf spot, is safe to banana plants and has no phytotoxicity.

Example 5

This example determines the field efficacy of Streptomyces parvus broth dry (denoted as SP) in combination with one of pyraclostrobin (denoted as PSN) and isopyrazam (denoted as IZM) on citrus anthracnose.

The test was carried out in Ganzhou city, Jiangxi province, Citrus plantation. The test agents and the amounts are detailed in table 8. Blank control is additionally arranged, each treatment is repeated for 4 times, 5 citrus trees are arranged in each cell, 48 cells are totally arranged, random blocks are arranged, and protective plants are arranged in intervals. The whole plant is uniformly sprayed by adopting a conventional spraying method. The application is carried out 1 time respectively in the young fruit stage and the fruit expansion stage of the citrus for 2 times in total.

The investigation and statistical method comprises the following steps:

disease index surveys are conducted 14 days after the first medicine and 14 days after the second medicine, 3 citrus trees are surveyed randomly in each cell, samples are taken from each plant according to east, west, south and north, 25 fruits are surveyed at each point, the total number of the surveyed fruits and the number of diseased fruits at each level are recorded, the disease index is calculated, and the results are shown in table 8.

The classification standard is as follows:

level 0: no disease;

level 1: the area of the connected disease spots accounts for less than 5% of the whole fruit area;

and 3, level: the area of the connected disease spots accounts for 5 to 10 percent of the whole fruit area;

and 5, stage: the connected area of the disease spots accounts for 11 to 25 percent of the whole fruit area;

and 7, stage: the area of the connected disease spots accounts for 26-50% of the whole fruit area;

and 9, stage: the area of the connected disease spots accounts for more than 50 percent of the whole fruit area.

The calculation method of disease index and prevention and treatment effect comprises the following steps:

TABLE 8 field efficacy against citrus anthracnose

The results in table 8 show that compared with the single dose of the Streptomyces parvus fermentation broth dry product, the pyraclostrobin and the isopyrazam, the combined preparation (WP) of the Streptomyces parvus fermentation broth dry product and the pyraclostrobin and the isopyrazam is obviously improved in field pesticide effect on the citrus anthracnose, is safe to citrus plants and has no phytotoxicity.

Example 6

This example determines the field efficacy of Streptomyces parvus broth dry (denoted as SP) in combination with one of pyraclostrobin (denoted as PSN) and isopyrazam (denoted as IZM) on strawberry powdery mildew.

The test was carried out on strawberry in Xingping city, Shaanxi province. The test method refers to the GB/T17980.119-2004 pesticide field efficacy test criterion (pesticide efficacy test for preventing and treating strawberry powdery mildew with bactericide). The test agents and the dosages are shown in Table 9. Another blank control was set, with 4 replicates per treatment, 20 strawberries per cell, 48 cells total, randomized block permutation. The whole plant is uniformly sprayed by adopting a conventional spraying method. The application for the 1 st time is carried out at the early stage of strawberry powdery mildew, and the application for the second time is carried out 14 days later, and the application is carried out for 2 times in total.

The investigation and statistical method comprises the following steps:

disease index surveys are conducted 14 days after the first medicine and 14 days after the second medicine, 5 points are surveyed randomly in each cell, all leaves of 3 plants are surveyed at each point, each leaf is recorded according to the percentage of scab to the leaf area in a grading mode, the total leaf number and the leaf number of each grade of disease are recorded and surveyed, the disease index is calculated, and the results are shown in a table 9.

The classification standard is as follows:

level 0: no disease;

TABLE 9 field drug effect for controlling strawberry powdery mildew

The results in table 9 show that compared with the single agents of the Streptomyces parvus fermentation broth dry product, the pyraclostrobin and the isopyrazam, the combined preparation (WP) of the Streptomyces parvus fermentation broth dry product, the pyraclostrobin and the isopyrazam is obviously improved in the field efficacy on strawberry powdery mildew, is safe to strawberry plants and has no phytotoxicity.

In conclusion, the composition is prepared by compounding two active ingredients, the activity and the bactericidal effect of the composition are not simple superposition of the activities of the ingredients, and compared with the existing single preparation, the composition has obvious bactericidal effect, obvious synergistic effect and good safety to crops and meets the safety requirement of pesticide preparations.

Claims

1. An agricultural sterilization composition comprises a sterilization component, a sterilization component and a fungicide, wherein the sterilization component comprises a dried streptomyces parvus fermentation liquor and one of pyraclostrobin and isopyrazam;

the mass ratio of the dried Streptomyces parvus fermentation liquor to the isopyrazam is 40: 1-1: 10.

2. The agricultural bactericidal composition as set forth in claim 1, wherein the dried product of the fermentation broth of streptomyces parvus is prepared by: the bacterial cells of Streptomyces parvus were removed by filtration, and the resulting sterile filtrate was spray-dried at an inlet air temperature of 115 ℃ with a feed amount of 6%.

3. The agricultural fungicidal composition according to claim 1, wherein the process for preparing the Streptomyces parvus fermentation broth comprises: inoculating streptomyces parvus into a seed culture medium, and performing amplification culture to obtain a fermentation strain; inoculating fermentation strain into fermentation tank, stirring, and fermenting;

setting fermentation parameters: the liquid loading amount is 20L/50L, the initial pH value is 7.5, the rotating speed is 130rpm, the fermentation temperature is 28 ℃, and the fermentation time is 5 d;

the fermentation medium comprises the following components: 5g of soluble corn starch, 2g of corn steep liquor, 4g of peptone, 1g of soluble cellulose, 5g of glucose, 0.5g of dipotassium hydrogen phosphate, 3g of calcium carbonate, 0.5g of sodium chloride and 0.5g of magnesium sulfate.

4. Use of the agricultural fungicidal composition according to any one of claims 1 to 3 for controlling crop diseases.

5. Use according to claim 4, wherein the crop diseases comprise banana leaf spot, cucumber powdery mildew, citrus anthracnose, strawberry powdery mildew.

6. The use of claim 4, wherein the agricultural bactericidal composition is prepared for use in a formulation for controlling crop diseases.