CN108450463B

CN108450463B - Synergistic application of farnesol to triazole bactericide in preventing and treating powdery mildew

Info

Publication number: CN108450463B
Application number: CN201810279387.7A
Authority: CN
Inventors: 常长青; 仇善旭; 蔡恩平; 吴熔熔; 王雨婷; 李玲玉; 姜子德
Original assignee: South China Agricultural University
Current assignee: South China Agricultural University
Priority date: 2018-04-01
Filing date: 2018-04-01
Publication date: 2020-07-14
Anticipated expiration: 2038-04-01
Also published as: CN108450463A

Abstract

The invention discloses application of farnesol and triazole fungicide in preventing and controlling ustilago (A) by spore accumulationSporisorium) And Ustilago genus (Ustilago) The new application of the sterilization and synergism of the sugarcane smut, the corn smut and the smut of other crops and the like caused by the sugarcane smut, the corn smut and the smut of other crops. The farnesol and the triazole bactericide have obvious synergistic effect, can greatly reduce the use amount of chemical pesticides, has obviously better prevention and treatment effect than that of a single medicament, and has good application prospect.

Description

Synergistic application of farnesol to triazole bactericide in preventing and treating powdery mildew

Technical Field

The invention relates to the technical field of biological control, in particular to a synergistic effect of farnesol and triazole bactericide, which is mainly applied to control sugarcane smut, corn smut and smut of Farnesoid and Farnesoidsporisorium) And Ustilago genus (Ustilago) Causing black powdery mildew of other crops and the like.

Background

Sugarcane is a main raw material in the sugar industry of China, corn is a main grain crop, and the sugarcane, the corn and the corn are also important feed crops and biomass energy materials. Disease infestation is a serious problem that has plagued its development.

The smut of sugarcane is caused by Sporoxylum (Sporoxylum)sporisorium) The infection is caused. The corn smut is caused by smut genus (Hemie)Ustilago) The infection is caused. The two pathogenic bacteria are two types of fungi and also belong to semi-specific parasitic bacteria, haploid does not attack, and double-core mycelium formed by sexual cooperation infects sugarcane, corn or other plants, so that the yield of crops is reduced, and the quality of the crops is reduced.

Farnesol (Farnesol) is a natural product extracted from plants or microorganisms, is environment-friendly, safe and nontoxic, is also called as alloy albizim alcohol and 3,7, 11-trimethyl-2, 6, 10-dodecatrien-1-ol, and has the following structural formula:

。

farnesol isomers are mainly divided into trans-trans, trans-cis, cis-trans and cis-cis, and various researches show that Farnesol (Farnesol) can regulate the growth and proliferation activities of microorganisms such as bacteria, fungi and the like.

At present, measures adopted for preventing and treating sugarcane smut and corn smut comprise breeding disease-resistant varieties and chemical prevention and treatment. The triazole fungicide is a broad-spectrum, high-efficiency and internal absorption and transportation-conductive fungicide, and hexaconazole and difenoconazole are two representative varieties of the triazole fungicide, are main chemical agents for preventing and treating ustilago at present, and have good prevention and treatment effects. But the pesticide residue is serious and easy to cause environmental pollution because the detention period of the pesticide residue in water and soil is longer. The effect of developing the synergist is particularly prominent for reducing the field dosage of the pesticide.

Disclosure of Invention

The invention aims to provide a new application of farnesol in preventing and treating smut pathogenic bacteria.

The purpose of the invention is realized by the following technical scheme:

the invention provides application of farnesol in the synergistic action of triazole fungicide in preventing and treating powdery mildew; the smut mainly includes sugarcane smut, corn smut and other crop smut caused by smut and smut.

The application, in particular to the smut, which is sugarcane smut and corn smut.

The use concentration of the farnesol is 0.01-1 mu M, preferably 0.04-0.5 mu M, and the farnesol is mixed with the triazole bactericide for use so as to increase the control effect.

The triazole fungicide is difenoconazole and hexaconazole.

Preferably, the difenoconazole is a 10% microemulsion, and the use concentration is 5000-200000 times of dilution.

Preferably, the hexaconazole is 30% microemulsion, and the concentration of hexaconazole is 100000-400000 times diluted.

More preferably, the toxicity to the proliferation of the smut bacterium sugarcane is 0.15 mu M of farnesol and 2 × 10 diluted by⁵The difenoconazole microemulsion with 10 percent times of the total weight is mixed for use, or the mixture ratio of the farnesol and the hexaconazole is 0.2 mu M of the farnesol plus the diluted 4 × 10⁵30% hexaconazole microemulsion;

more preferably, for the corn smut, the mixing ratio of the farnesol and the difenoconazole is 0.2 mu M of the farnesol plus the dilution 2 × 10⁵A 10% difenoconazole microemulsion.

The farnesol is obtained by purchasing, and can also be obtained by extracting plants or microorganisms. The farnesol and the triazole bactericide (difenoconazole and/or hexaconazole) are mixed in different proportions to treat sugarcane smut pathogen basidiospore and corn smut pathogen basidiospore, and the inhibition rate, the synergy ratio and the colony growth condition are counted to determine that the blending use of the farnesol and the triazole bactericide can obviously improve the antibacterial action and greatly reduce the use amount of the triazole bactericide. Therefore, the triazole fungicide has good prospect as a synergist for preventing and treating the pathogenic bacteria of the smut.

Based on the control of the later production and application cost, the invention provides a method for preventing and treating sugarcane smut and corn smut by mixing farnesol and triazole bactericide in a concentration range of 0.01-1 mu M.

Compared with the prior art, the invention has the following beneficial effects:

1) at present, the recommended dosage of 10 percent difenoconazole microemulsion in the field is 4000-10000 times of that of diluted difenoconazole, and the optimal mixing ratio of the toxicity of the smut bacteria in the invention is 0.15 mu M + diluted 2 × 10⁵The dosage of the difenoconazole microemulsion with 10 percent times is reduced by 20 times, the synergistic ratio is up to 74 times, the recommended dosage of the 30 percent hexaconazole suspending agent in the field is 1000-fold and 5000 times, and the optimal mixing ratio for the toxic action of the ustilago is 0.2 mu M plus diluted 4 × 10⁵The dosage of the hexaconazole is reduced by 80 times, and the synergistic ratio reaches 62 times.

2) Farnesol (Farnesol) is a natural product extracted from plants or microorganisms, and has certain influence on hypha formation, biofilm formation, certain oxidative stress reaction and cell morphology regulation of microorganisms such as bacteria and fungi. The invention researches the farnesol as a synergist to prevent and treat smut for the first time, and compared with the traditional synergist, the farnesol as the synergist has the advantages of greenness, safety, natural existence in the environment, capability of being degraded by soil microorganisms, and the like, and has novelty.

Drawings

FIG. 1 shows the bacteriostatic effect of the mixture of farnesol and difenoconazole on sugarcane smut, wherein the ratio of 1: 0.05. mu.mFarnesol and the dilution of difenoconazole is 1 × 10⁵Double, 0.025 μm Farnesol + Difenoconazole Dilute 2 × 10⁵2: 0.08 μm Farnesol, 5 × 10 diluted with difenoconazole⁴Double, 0.04 μm Farnesol + Difenoconazole Dilute 1 × 10⁵3: 0.1 μm Farnesol, 3.34 × 10 diluted with difenoconazole⁴Double, 0.05 μm Farnesol + Difenoconazole Dilute 6.68 × 10⁴4: 0.2 μm Farnesol, 2 × 10 diluted with difenoconazole⁴Double, 0.1 μm Farnesol + Difenoconazole Dilute 4 × 10⁴5: 0.3 μm Farnesol, 1.25 × 10 diluted with difenoconazole⁴Double, 0.15 μm Farnesol + Difenoconazole Dilute 2.5 × 10⁴6: 0.2 μm Farnesol, Difenoconazole Dilute 1 × 10⁴Double, 0.1 μm Farnesol + Difenoconazole Dilute 2 × 10⁴Fold, 7: 0.225 μm Farnesol, Difenoconazole Dilute 6.67 × 10³Double, 0.1125 μm Farnesol + Difenoconazole Dilute 1.33 × 10⁴8: 0.25 μm Farnesol, 5 × 10 diluted with difenoconazole³Fold, 0.125 μm Farnesol + Difenoconazole Dilute 1 × 10⁴And (4) doubling.

FIG. 2 shows the effect of farnesol and difenoconazole on the virucity of sugarcane smut, wherein A is CK; b, diluting difenoconazole by 5000 times; c, 0.5 mu MFarnesol; d, diluting difenoconazole by 10000 times and 0.25 mu M Farnesol.

FIG. 3 shows the toxicity synergism of farnesol on difenoconazole for sugarcane smut, wherein Dif (difenoconazole) is diluted to 1 × 10⁵Fold, 2: 0.4. mu.M Farnesol, 3: Dif (difenoconazole) dilution 2 × 10⁵Double + 0.1. mu.M Farnesol 4: Dif (difenoconazole) dilution 2 × 10⁵Double + 0.15. mu.M Farnesol, 5: Dif (difenoconazole) dilution 2 × 10⁵Fold + 0.2. mu.M Farnesol.

FIG. 4 is the optimum mixing ratio of farnesol and difenoconazole for inhibition of smut sugar cane, wherein Dif (difenoconazole) is diluted 2 × 10⁴Doubling; far 0.08. mu.M Farnesol.

FIG. 5 is a graph showing the effect of farnesol and difenoconazole on Ustilago zeae in a mixed mode, wherein A is CK and B is Dif (difenoconazole) diluted 1 × 10⁵C0.4. mu.M Farnesol, D0.2. mu.M Farnesol + Dif (difenoconazole) dilution 2 × 10⁵And (4) doubling.

FIG. 6 shows the effect of farnesol and hexaconazole on the virus resistance of sugarcane smut, wherein A is CK and B is hexaconazole diluted 2 × 10⁵0.2 mu M Farnesol C, 0.3 mu M Farnesol D, 0.5 mu M Farnesol E, hexaconazole 2 × 10⁵Farnesol + 0.1. mu.M, G hexaconazole 2 × 10⁵Farnesol + 0.15. mu.M H hexaconazole 2 × 10⁵Fold +0.25 μ MFarnesol.

FIG. 7 is a graph of the virulence potentiation of hexaconazole by farnesol (smut of sugarcane), wherein the 1: Hex (hexaconazole) dilution 2 × 10⁵Double, 2:0.4 μ MFarnesol, 3: Hex (hexaconazole) dilution 4 × 10⁵Double + 0.1. mu.M Farnesol 4: Hex (hexaconazole) dilution 4 × 10⁵Double + 0.15. mu.M Farnesol, 5: Hex (hexaconazole) dilution 4 × 10⁵Fold + 0.2. mu.M Farnesol.

FIG. 8 shows the bacteriostatic effect of blending farnesol and hexaconazole on smut of sugarcane, 1: 0.08. mu.Mfarnesol, hexaconazole diluted 2 × 10⁵Double, 0.04. mu.M Farnesol + hexaconazole dilution 4 × 10⁵2: 0.1. mu.M farnesol, hexaconazole dilution 2 × 10⁵Double, 0.05. mu.M Farnesol + hexaconazole dilution 4 × 10⁵Doubling, 3: 0.2. mu.M farnesol, hexaconazole dilution 2 × 10⁵Double, 0.1. mu.M Farnesol + hexaconazole dilution 4 × 10⁵4: 0.3. mu.M farnesol, hexaconazole diluted 2 × 10⁵Double, 0.15. mu.Mfarnesol + hexaconazole dilution 4 × 10⁵5: 0.4. mu.M farnesol, hexaconazole diluted 2 × 10⁵Double, 0.2. mu.M Farnesol + hexaconazole dilution 4 × 10⁵6: 0.5. mu.M farnesol, hexaconazole diluted 2 × 10⁵Double, 0.25. mu.M Farnesol + hexaconazole dilution 4 × 10⁵And (4) doubling.

Detailed Description

The invention is further illustrated by the following detailed description of specific embodiments, which are not intended to be limiting but are merely exemplary.

Test material

Farnesol was purchased from sigma, Inc., CAS Number: 4602-84-0. Diluting the farnesol into a mother liquor with the concentration of 3.98mM by using absolute ethyl alcohol for later use. The 10 percent of difenoconazole microemulsion and the 30 percent of hexaconazole suspending agent are both produced by the plant protection institute of Chinese academy of agricultural sciences. The sugarcane smut pathogen winter spores to be tested are collected from sugarcane smut plants which are naturally attacked in Guangxi fields, the sugarcane smut pathogen basidiospores WT17 and WT18 to be tested are obtained by separating the winter spores on the sugarcane smut plants, the two haploid is identified as plus and minus respectively, the haploid can be mutually identified, sexual coordination is carried out to generate diploid hyphae, and U9 and U10 (maize smut basidiospores) are laboratory preservation strains. The culture solution used in the laboratory was YEPSA +0.05% glycerol.

Test medium

YEPSA culture medium, namely 10 g of yeast extract, 20 g of peptone, 20 g of sucrose and 18 g of agar, adding deionized water to the volume of the mixture to be 1000 m L, and then performing conventional sterilization, YEPS liquid culture medium, namely YEPSA culture medium without agar, wherein 0.5% of glycerol is added to the culture medium for assisting dissolution when the culture medium is used.

Example one

On the basis of the preliminary test, the farnesol and the 10 percent difenoconazole microemulsion are prepared into mother liquor with a certain concentration gradient according to the proportion for standby (the farnesol is 0.05 mu M, 0.08 mu M, 0.1 mu M, 0.2 mu M, 0.3 mu M, 0.4 mu M and 0.5 mu M; the 10 percent difenoconazole microemulsion (dilution): 1 × 10⁵5 × 10 times of⁴3.34 × 10⁴2 × 10⁴1.25 × 10⁴Double, 1 × 10⁴6.67 × 10³5 × 10 times of³Double), pick a little sugarcane smut bacterium basidiospore from the plate to culture in 6m L YEPS culture solution overnight as seed solution, centrifugally collect the thallus the next day, and re-suspend the thallus (OD) with YEPS liquid culture medium₆₀₀0.2) for standby, respectively sucking mother liquor with different concentrations of 300 mu L into a sterilized centrifuge tube with the concentration of 2m L, adding the basidiospore suspension with the same amount, uniformly mixing to form an independent use group, respectively sucking mother liquor with different concentrations of farnesol, the mother liquor with the concentration of 250 mu L and the mother liquor with the concentration of 250 mu L, mixing in a sterilized centrifuge tube with the concentration of 5m L, adding the bacteria liquid with the same volume, uniformly mixing to form a mixed group, sucking a sterilized centrifuge tube with the concentration of YEPS, the concentration of 500 mu L into the sterilized centrifuge tube with the concentration of 5m L, adding the bacteria liquid with the same volume, uniformly mixing to form a control group₆₀₀Thereafter, the cells were incubated at 28 ℃ for 20 hours in a shaker at 200rpm/min, and the final OD of each treatment was measured₆₀₀By calculating OD₆₀₀The net growth amount was determined to obtain the inhibition ratio.

The experimental result shows (see figure 1), the mixing use effect of the farnesol and the difenoconazole is obviously better than the inhibition effect of single use and concentration expansion, the optimal mixing group for inhibiting the ustilago saccharatum is 0.025 mu M farnesol + diluted 2 × 10⁵The inhibition effect of the difenoconazole is more than 99 percent, while the farnesol inhibition rate of 0.05 mu M is only 6 percent, and the difenoconazole is diluted to 1 × 10⁵The inhibition ratio of difenoconazole is 25%. only when difenoconazole is diluted to 5 × 10³The inhibition rate reaches 98 percent in times.

Example two

On the basis of a preliminary test, firstly preparing the farnesol and 10% difenoconazole microemulsion into mother liquor with a certain concentration gradient according to a certain proportion for later use (0.5 mu M of farnesol and 5000 times of dilution of the 10% difenoconazole microemulsion), selecting a little of saccharomycete aschersonia from a flat plate, culturing the saccharomycete aschersonia in 6M L YEPS culture solution overnight to be used as seed solution, transferring the seed solution to 500 mu L-50M L YEPS culture solution for enlarged culture (until OD is reached₆₀₀0.2), respectively sucking mother liquor of 500 mu L to 5m L sterilized centrifuge tubes with different concentrations, adding bacterial liquid with the same volume, mixing uniformly, then removing 250 mu L farnesol and 250 mu L to dilute 10% difenoconazole microemulsion with 5000 times of concentration to the 5m L sterilized centrifuge tube, adding bacterial liquid with the same volume, mixing uniformly, adding bacterial liquid with the same volume to 500 mu L YEPS to the 5m L sterilized centrifuge tube, mixing uniformly, placing in a shaker at 28 ℃ and 200rpm/min for culturing for 24h, and then diluting 10 bacterial liquid treated with each concentration by using fresh YEPS liquid culture medium³And taking 200 mu L to be coated on a YEPSA solid culture medium, placing the YEPSA solid culture medium in an incubator at 28 ℃ for standing culture for 48h, and finally determining the toxicity effect of the farnesol and 10% difenoconazole microemulsion on the proliferation of the Ustilago virens.

The experimental result shows (see fig. 2) that difenoconazole and farnesol with certain concentrations in the graph have inhibition effects on the proliferation and growth of smut sugarcane, and when the concentrations of the difenoconazole and the farnesol are reduced to 1/2, the difenoconazole and the farnesol are mixed with each other, so that the toxicity effect is more obvious.

On the basis, the use concentration of the farnesol is continuously reduced, and the lowest effective concentration of the farnesol is sought, wherein the control group is independently used, namely the farnesol is 0.4 mu M, and the 10 percent of difenoconazole microemulsion is 1 × 10⁵0.1 mu M +2 × 10 percent of mixed group (farnesol +10 percent difenoconazole microemulsion)⁵0.15. mu.M +2 × 10⁵0.2. mu.M +2 × 10⁵Doubling; control group: YEPS, process the same. Culturing at 28 deg.C in a shaker at 200rpm/min for 24 hr. The treated bacterial solutions at each concentration were subsequently diluted 10 with fresh YEPS broth⁴And (4) absorbing 200 mu L, spreading on a YEPSA solid culture medium, placing in an incubator at 28 ℃ for standing culture for 48h, counting the number of colonies treated, and calculating the synergy ratio of each treatment group by taking the synergy of the control group as 1.

The results of the experiments show (please seeFIG. 3) shows that the effect of the mixture of farnesol and 10% difenoconazole microemulsion is more obvious than that of the mixture of the farnesol and the 10% difenoconazole microemulsion which are used independently and the concentration of the difenoconazole microemulsion is doubled, which indicates that the farnesol and the difenoconazole have synergistic action, the graph shows that the synergistic action is continuously increased along with the increase of the concentration of the farnesol, and the optimal mixture ratio of the farnesol and the difenoconazole to the multiplication toxicity of the smut bacteria is 0.15 mu M + diluted 2 × 10⁵The synergistic ratio of the 10 percent difenoconazole microemulsion is 74 times.

EXAMPLE III

On the basis of a preliminary test, firstly, preparing the farnesol and 10% difenoconazole microemulsion into mother liquor with a certain concentration gradient for later use (the farnesol: 0.08 mu M, 10% difenoconazole microemulsion: diluted 2 × 10)⁴Double), selecting a little sugarcane smut bacterium basidiospore from the plate, culturing in 6m L YEPS culture solution overnight as seed solution, transferring to 500 mu L-50 m L YEPS culture solution the next day for expansion culture (to OD)₆₀₀Is 0.2) for standby, the concentration of the farnesol is controlled to be 0.08 mu M, and the concentration dilution of the difenoconazole is prepared to be 2 × 10⁴Multiplying, then setting gradient to dilute to 0.5 times, 0.4 times, 0.25 times, 0.1 times and 0.05 times of the mother liquor, mixing farnesol with 250 mu L and difenoconazole with the same volume and different concentrations in a centrifuge tube, respectively taking the farnesol with 500 mu L and the mother liquor of azoxystrobin as independent groups, taking 500 mu L YEPS as a blank control, repeatedly setting, adding 500 mu L bacterial liquid in all the centrifuge tubes, uniformly mixing, culturing for 20h in a shaker at 28 ℃, 200rpm/min, and measuring the final OD of each treatment₆₀₀By calculating OD₆₀₀And (4) obtaining the inhibition rate by the net growth amount to obtain the optimal mixed group for inhibiting the smut bacteria.

Referring to FIG. 4, the experimental results show that Farnesol and difenoconazole have synergistic effect on controlling ustilago graminis and that the dosage of chemical agents can be greatly reduced by adding Farnesol, and when the concentration of the Farnesol is 0.04 mu M, the minimum concentration of the difenoconazole is 1 × 10⁵The inhibition rate is 0.91, which is higher than the effect of single use.

(as shown in FIG. 4, group 7, 0.05Dif +0.5Far, i.e., 1 × 10⁵Double +0.04 μ M)

Example four

On the basis of preliminary tests, the farnesol and 10% of difenoconazole microemulsion are prepared into the product of 0.4 mu M farnesol and 1 × 10 diluted by 10% of difenoconazole microemulsion⁵Selecting a little corn smut bacteria basidiospore from the plate, culturing in 6m L YEPS culture solution overnight as seed solution, transferring to 500 mu L-50 m L YEPS culture solution the next day, and performing amplification culture (to OD₆₀₀0.2) for use, 0.4. mu.M farnesol and dilution 1 × 10, respectively⁵Putting the mother liquor of difenoconazole and YEPS of 500 mu L respectively into different sterilized centrifuge tubes, and taking 0.4 mu M farnesol and diluting 1 × 10⁵250 mu L of each difenoconazole mother liquor is put into the same centrifuge tube, 500 mu L bacterial suspension is added into each centrifuge tube, three groups of the centrifugal tubes are arranged for repetition, the centrifuge tube is placed into a shaker at 28 ℃ and 200rpm/min for culturing for 24h, and then the bacterial liquid treated in each centrifuge tube is diluted by 10 times by using fresh YEPS liquid culture medium⁵And taking 200 mu L, spreading on a YEPSA solid culture medium, placing in an incubator at 28 ℃ for standing culture for 48h, counting the number of colonies, and observing the gain effect.

The results show (see FIG. 5) 0.2. mu.M farnesol + Dilute 2 × 10⁵The mixing ratio of the 10 percent difenoconazole microemulsion is also suitable for inhibiting the proliferation and growth of the corn smut, and the figure shows that the inhibiting effect of the 0.4 mu M farnesol and the difenoconazole is obviously not mixed and the inhibiting effect achieved when the concentration is reduced by half is good, when the 0.2 mu M farnesol and the diluted 2 × 10⁵The toxicity of the microemulsion of 10 percent difenoconazole to the maize smut is higher than 95 percent.

EXAMPLE five

On the basis of the preliminary test, firstly, the farnesol and 30% hexaconazole suspending agent are prepared into mother liquor with a certain concentration gradient according to the proportion for standby (farnesol: 0.2 mu M, 0.3 mu M, 0.5 mu M; 30% hexaconazole suspending agent (dilution): 2 × 10⁵Twice, twice) selecting a little sugarcane smut bacteria basidiospore from a flat plate to be cultured in 6m L YEPS culture solution overnight to be used as seed solution, transferring the seed solution to 500 mu L to 50m L YEPS culture solution for enlarged culture (until OD600 is 0.2) the next day, respectively sucking mother liquor with different concentrations from 500 mu L to 5m L into a sterilized centrifuge tube, adding bacterial liquid with the same volume to be mixed and marking as an independent use group, and respectively sucking mother liquor with different concentrations of farnesol250 mu L and 250 mu L hexaconazole mother solution are mixed in a 5m L sterilized centrifuge tube, equal volume of bacterial liquid is added and mixed to be recorded as a mixed use group, YEPS500 mu L to 5m L sterilized centrifuge tube is sucked to be added and mixed to be recorded as a control group, the control group is placed in a shaker at 28 ℃ and 200rpm/min for culturing for 24h, then fresh YEPS liquid culture medium is used for diluting bacterial liquid with each concentration for 103 times, 200 mu L is sucked to be coated on YEPSA solid culture medium and placed in a 28 ℃ incubator for standing and culturing for 48h, and finally, the toxicity effect of farnesol and 30 percent hexaconazole suspending agent on the proliferation of ustilago charitis is determined (figure 6)

On the basis, the use concentration of the farnesol is continuously reduced, and the minimum effective concentration of the farnesol is sought, wherein the control group comprises 0.4 mu M of the farnesol and 30 percent of hexaconazole suspending agent 2 × 10⁵0.1 mu M +4 × 10 of mixed component (farnesol +30% hexaconazole suspending agent)⁵0.15. mu.M +4 × 10⁵0.2. mu.M +4 × 10⁵Doubling; control group: YEPS, process the same. Culturing at 28 deg.C in a shaker at 200rpm/min for 24 hr. The treated bacterial solutions at each concentration were subsequently diluted 10 with fresh YEPS broth⁴And (4) absorbing 200 mu L, spreading on a YEPSA solid culture medium, placing in an incubator at 28 ℃ for standing culture for 48h, counting the number of colonies treated, and calculating the synergy ratio of each treatment group by taking the synergy of the control group as 1.

The experimental results show (see fig. 7) that the effect of blending farnesol and 30% hexaconazole suspending agent is more obvious than that of single use and concentration is expanded by one time, which indicates that the two suspending agents have synergistic effect, and the graph shows that the synergistic effect is continuously increased along with the increase of the concentration of the farnesol, and the optimal mixing ratio for the multiplication toxicity of the smut of sugarcane is 0.2 mu M + diluted 4 × 10⁵The efficiency of the hexaconazole is 62 times.

EXAMPLE six

On the basis of the preliminary test, firstly, preparing the farnesol and 30% hexaconazole suspending agent into mother liquor with a certain concentration gradient according to the proportion for standby (0.08 MuM, 0.1 MuM, 0.2 MuM, 0.3 MuM, 0.4 MuM, 0.5 MuM for farnesol; 30% hexaconazole suspending agent (dilution): 2 × 10⁵Doubling) a little of sugarcane smut bacteria basidiospore from the flat plate is picked up at 6m L YOvernight culture in EPS culture medium as seed liquid, centrifuging the next day to collect thallus, and resuspending thallus (OD) in YEPS liquid culture medium₆₀₀0.2) for standby, respectively sucking mother liquor with different concentrations of 300 mu L into a sterilized centrifuge tube with the diameter of 2m L, respectively sucking mother liquor with the diameter of 150 mu L farnesol and mother liquor with the diameter of 150 mu L hexaconazole, respectively mixing the mother liquor and the mother liquor in the sterilized centrifuge tube with the diameter of 2m L, using 300YEPS as a control, adding the basidiospore suspension with the same amount, uniformly mixing, setting three times for each concentration treatment, and then measuring the initial OD (optical density) of each treatment by using a spectrophotometer₆₀₀Thereafter, the cells were incubated at 28 ℃ for 20 hours in a shaker at 200rpm/min, and the final OD of each treatment was measured₆₀₀By calculating OD₆₀₀The net growth was evaluated to determine the inhibition ratio (FIG. 8).

Referring to fig. 8, the blending effect of farnesol and 30% hexaconazole suspending agent is obviously better than that of single use and the synergistic effect of the suspending agent is also obvious, namely, 0.04 mu M farnesol and dilution 4 × 10⁵The inhibition rate of hexaconazole reaches 94 percent, and the hexaconazole is diluted to 2 × 10⁵The inhibition rate of farnesol is 74% and the inhibition rate of farnesol at 0.08. mu.M is 8%.

Claims

1. The application of farnesol in the synergistic effect of the triazole fungicide in preventing and treating the powdery mildew is that the triazole fungicide is difenoconazole and hexaconazole.

2. Use according to claim 1, wherein the smut is crop smut caused by smut or smut.

3. Use according to claim 2, wherein the smut is crop smut caused by smut from sugar cane or corn.

4. Use according to claim 1 or 2, wherein farnesol is used in a concentration of 0.01 μ M to 1 μ M.

5. The use according to claim 4, wherein the difenoconazole is a 10% microemulsion used at a concentration of 5000 to 200000 times dilution.

6. The use according to claim 4, wherein hexaconazole is 30% microemulsion and is used in a concentration of 100000-400000 times diluted.

7. The use of claim 4, wherein the mixing ratio of the farnesol and the difenoconazole is 0.15 μ M for the proliferation toxicity of the smut bacteria, namely the farnesol + the diluted 2 × 10⁵A 10% difenoconazole microemulsion.

8. The use of claim 4, wherein the ratio of farnesol to difenoconazole is 0.2 μ M farnesol + diluted 2 × 10 for the multiplication toxicity of smut corn⁵A 10% difenoconazole microemulsion.

9. The use of claim 4, wherein the mixture ratio of farnesol and difenoconazole is 0.04 μ M farnesol + diluted 4 × 10 for the inhibition of smut bacteria⁵A 10% difenoconazole microemulsion.

10. The use of claim 4, wherein the farnesol and hexaconazole are mixed in a ratio of 0.2 μ M farnesol + diluted 4 × 10 for the multiplication virulence of smut sugarcane⁵30% hexaconazole microemulsion.