CN110129209B

CN110129209B - Violet purpurea fungus strain and application thereof

Info

Publication number: CN110129209B
Application number: CN201910398095.XA
Authority: CN
Inventors: 洪永生; 伍建榕; 马焕成; 魏玉倩; 洪英娣; 马翔; 张东华; 闫晓慧
Original assignee: Southwest Forestry University
Current assignee: Southwest Forestry University
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2022-05-20
Anticipated expiration: 2039-05-14
Also published as: CN110129209A

Abstract

The invention discloses a lilac violet fungus strain and application thereof, wherein the lilac violet fungus strain is classified and namedPurpureocillium lilacinumAnd the preservation unit: china general microbiological culture Collection center (CGMCC), preservation date: 28/12/2018, accession number: CGMCC No.17067, wherein the lilac purple fungus belongs to the fungus kingdom, Eumycota, fungi imperfecti, order hyphomycetales, family hyphomycetaceae, genus lilac purple. The application is the application of the lilac purple fungus strain in preparing biological preparations for preventing and controlling fire ants.

Description

Violet purpurea fungus strain and application thereof

Technical Field

The invention belongs to the technical field of microorganism separation culture, and particularly relates to a lilac violet fungus strain and application thereof.

Background

In 23.9.2004, plant quarantine stations in Wuchuan city reported that local solenopsis invicta was seriously harmed. In 17 days 1 month 2005, red imported fire ants were added to national plant inspection pests, national plant quarantine pests, national forestry quarantine pests and national forestry dangerous pests.

The rapid invasion of the solenopsis invicta is benefited by strong fecundity and attack capability, the population growth is rapid, and the high density of ant nests is caused. The red imported fire ants are from south america, are feeding insects and arthropods, sometimes also feed eggs of small mammals, lizards, birds and birds, and also feed seeds, buds, fruits and the like of various crops to influence the growth of the crops. Solenopsis invicta often damages utility electronics equipment, causing utility failure. Red fire ants have toxic capsules and stings and can continuously sting, people with sensitive physique can cause death because toxic proteins generate allergic reaction. Areas invaded by the solenopsis invicta will be rapidly increased in the future, and the use amount of chemical agents is increased, but the traditional chemical control can cause serious 3R problem.

The biological control is an ideal and environment-friendly method for controlling the red imported fire ants. Entomogenous fungi, as a class of important pathogenic bacteria of pests, play an important role in the biological control of pests. The entomopathogenic fungi can be prepared into microbial preparations after development, is convenient to use, has high biological safety to human and livestock, and has no concern about environmental pollution and residual quantity.

The natural pathogenic bacteria of Solenopsis invicta (Burm) pers are separated from Solenopsis invicta (Burm) pers by Lianxi Yan of agricultural university in south ChinaPenicillium (A. penicillium)Paecilomyces lilacinus) The result of the strain shows that the highest pathogenicity strain paecilomyces lilacinus PL04 has the highest death rate of 70.60 percent to 15d of red imported fire ant workers. Therefore, it is necessary to find pathogenic fungi of the solenopsis invicta, screen out strains with strong lethal toxicity to the solenopsis invicta, and further comprehensively control the harmful organisms of the solenopsis invicta.

Disclosure of Invention

The first purpose of the invention is to provide a purplish lilac fungus strain; the second purpose is to provide the application of the lilac purple fungus strain.

All percentages used in the present invention are volume percentages unless otherwise indicated.

The first object of the present invention is achieved by a fungus strain of the genus Viola ((A))Purpureocillium lilacinum) Designated PLHHYSFJ02, was identified as violet spore (synonyms: paecilomyces) fungal strains (A), (B)Purpureocillium lilacinum) The agent is separated from the natural lethal red imported fire ants, and the preservation unit is as follows: china general microbiological culture Collection center (CGMCC), preservation date: 28/12/2018, accession number: CGMCC No.17067, wherein the lilac purple fungus belongs to the fungus kingdom, Eumycota, fungi imperfecti, order hyphomycetales, family hyphomycetaceae, genus lilac purple.

The lilac violet purple mould (synonym: Paecilomyces) fungus strain of the invention (A)Purpureocillium lilacinum) The gene is named as PLHHYSFJ02, is separated from solenopsis invicta, and is preserved in China General Microbiological Culture Collection Center (China General Microbiological Culture Collection Center, CGMCC for short) in 28 days 12 and 12 months in 2018. The address is No. 3 of Xilu No.1 of Beijing, Chaoyang, the institute of microbiology, Chinese academy of sciences, zip code 100080). The preservation number is CGMCC No: 17067.

the strain has good pathogenic effect on the solenopsis invicta, can penetrate through the solenopsis invicta somites in a short time, parasitizes the solenopsis invicta and breeds.

The strain can rapidly propagate after contacting the solenopsis invicta.

The strain produces spores on the surface of the solenopsis invicta, and after the spores are produced, conidia are collected on the surface of the solenopsis invicta and are inoculated to the solenopsis invicta. The Koehz's law verifies that the same virulence lethal effect can be achieved when the conidia of the tie-back strain infects other solenopsis invicta used in health experiments.

The strain is obtained by the following specific steps:

A. collecting red imported fire ants: collecting live insects and naturally dead insects of the red imported fire ants, finding out the nest of the red imported fire ants, collecting and feeding the living insects and the naturally dead insects indoors.

B. Strain separation and screening: autoclave all required experimental materials and operate all steps in a sterile worktop.

Cleaning the solenopsis invicta dead naturally by using 75% of ethanol solution for 5 seconds, sterilizing the surface of the solenopsis invicta for 2-3 minutes by using 0.1% of mercuric chloride solution, slowly showering the surface of the solenopsis invicta for 3 times by using sterile water, separating the solenopsis invicta according to different parts of the head, the chest and the abdomen by using sterilized tweezers, and carefully placing different body parts of the separated solenopsis invicta into a culture medium.

The culture medium is a common PDA culture medium.

Transferring the mixture into a constant temperature incubator at 25 +/-for 5 d. The purification was repeated twice.

C. And (3) strain preservation: timely storing pathogenic strains of solenopsis invicta in a laboratory, selecting strains which grow vigorously in a propagation culture medium, inoculating the strains into a storage culture medium, performing static culture in the dark at 25 +/-7 ℃ for 7 days, and freezing and storing in a refrigerator at 4 ℃; the storage culture medium is a PDA culture medium; inoculating the strain to a slant of a common PDA test tube in a sterile operation box, culturing at 25 +/-7 days, and storing in a refrigerator at 4 ℃.

The components of the PDA solid medium in g/L are as follows: 160-240 g of potatoes, 10-20 g of glucose, 15-20 g of agar and natural PH.

The PDA solid medium preferably comprises the following components in g/L: 200g of potato, 20g of glucose, 20g of agar and natural PH.

The specimen in the step A is collected from the Dianlong district, the Yingong district, the Dongchuan district and the Dehong Dai Jingpo City of autonomous State mango.

The specimen collection in the step A is carried out on the road side, in the grassland, in the flower and tree clump soil and in the eucalyptus forest.

And B, collecting the specimen in the step A under the environment of drying and sufficient illumination.

And B, indoor feeding of the step A is complete nest feeding with red imported fire ants.

And step B, operating under an alcohol lamp, burning an inoculating needle and an inoculating loop on flame outer flame of the alcohol lamp, and operating all separation steps around the alcohol lamp.

And B, sterilizing materials required by tests such as an inoculating needle, an inoculating loop, sterile water, tweezers, a culture medium and the like in a high-pressure steam type sterilizer at the temperature of 121 ℃ for more than 30 minutes.

And step B, the sterile operating platform comprises the steps of inoculating the culture medium, and sealing all propagation culture media by a seal film imported from America.

Optimizing the propagation culture condition in the step B; and (5) carrying out static culture in the dark at 25 +/-9 d.

The conditions for the preservation and culture in the step C are preferred; and (3) carrying out dark static culture at 26 ℃ for 9 d.

A fungus of the genus lilium (synonym: Paecilomyces) and a method for biologically controlling the solenopsis invicta comprise the steps of strain activation and propagation, spore suspension preparation and solenopsis invicta death virulence detection, and specifically comprise the following steps:

A. strain activation and propagation: the fungus strain of the lilac purple spore fungus (synonym: Paecilomyces) is (A)Purpureocillium lilacinum) PLHHYSFJ02 is inoculated on an activation and propagation culture medium, and cultured for 15 days at 25 +/-DEG C until a large number of conidia are produced, so as to obtain the activation and propagation spore-producing strain.

B. Preparation of spore suspension: inoculating the strain on a PDA culture medium, and culturing for 15d in a constant temperature incubator at 25 ℃ +/-15 ℃.

Conidia in the culture dish were rinsed with sterile aqueous solution supplemented with 0.05% Tween-80. Pouring the bacteria liquid and spore in the culture dish into a cup, shaking for 30min, and filtering with a piece of lens wiping paperFinally, an countless spore suspension was obtained. Using a hemocytometer, placed under a microscope, the number of all conidia in the inner 400 compartments was recorded. Finally, the total spore number of the prepared spore suspension is calculated, and the prepared spore suspension is diluted to be 1.0 multiplied by 10⁷Each is mL⁻¹A spore suspension.

The preparation method can also comprise the step of preparing spore suspensions with other concentrations.

And the brand of the blood counting plate in the step B is a blood counting plate with 16 grids multiplied by 25 grids for precision finding in Shanghai.

And the Tween-80 is used as a fungal conidium dispersant, and the Tween-80 is polyoxyethylene sorbitan monooleate.

The second object of the invention is achieved by the use of said fungus strain of the genus violaxanthus for the preparation of a biological preparation for the biological control of fire ants.

And (3) biocontrol effect determination: uniformly coating insect-preventing escaping powder on the cup mouth of the plastic cup, and uniformly spraying 1.0 multiplied by 10 red fire ants in the plastic cup by using a small-sized spray can⁷each.mL⁻¹A spore suspension.

Transferring to an incubator for 10 days at constant temperature, opening the incubator every 24 hours, taking out the plastic cups, and recording the number of dead workers. And picking out the dead worker ants for moisturizing culture, checking whether fungi grow out, and comparing the reasons for the death of the worker ants of the solenopsis invicta. The cumulative mortality rate of workers is carefully calculated. The experiment was repeated three times.

The biocontrol effect of the present invention includes the following aspects.

1. The strain has good pathogenic effect on the solenopsis invicta, can penetrate through the joint of the solenopsis invicta in a short time, and parasitizes in the solenopsis invicta and propagates.

2. The strain of the invention has rapid growth and large spore yield, and is beneficial to large-scale production, popularization and application.

3. The biocontrol bacterium for the solenopsis invicta is obtained by separating the natural infection, death and separation of the solenopsis invicta under the natural environment condition, so that the biocontrol bacterium can be used as a biological control method for the solenopsis invicta, and has the advantages of simple operation process and good control effect.

Drawings

FIG. 1 shows the fungus strains of the purple lilac spore fungus (synonyms: Paecilomyces) of example 1: (Purpureocillium lilacinum) The colony positive morphology of the strain is obtained when the PLHHYSFJ02 is cultured on a common PDA culture medium for 7 d;

FIG. 2 shows the fungus strains of the purple lilac spore fungus (synonyms: Paecilomyces) of example 1: (Purpureocillium lilacinum) PLHHYSFJ02 conidiophore micrographs;

FIG. 3 shows the fungus strains of the purple lilac spore fungus (synonyms: Paecilomyces) of example 5: (Purpureocillium lilacinum) PLHHYSFJ02 hyphae and conidia;

FIG. 4 shows the P.lilacinus (synonym: Paecilomyces) fungal strain (A.sp.) (A.Purpureocillium lilacinum) The morphological characteristics of the PLHHYSFJ02 strain which infects solenopsis invicta in the nest, invades solenopsis invicta body node and is observed under the microscope of body growth and development;

FIG. 5 shows the fungus strains of the purple lilac spore fungus (synonym: Paecilomyces) of example 6: (Purpureocillium lilacinum) Infection of solenopsis invicta with PLHHYSFJ02 in the nest results in the death of solenopsis invicta.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to be limiting in any way, and any modifications or alterations based on the teachings of the present invention are intended to fall within the scope of the present invention.

The Classification and naming of the lilac purple fungus strainsPurpureocillium lilacinumAnd the preservation unit: china general microbiological culture Collection center (CGMCC), preservation date: 28/12/2018, accession number: CGMCC No.17067, wherein the lilac purple fungus belongs to the fungus kingdom, Eumycota, fungi imperfecti, order hyphomycetales, family hyphomycetaceae, genus lilac purple.

The application of the lilac purple fungus strain is the application of the lilac purple fungus strain in preparing biological preparations for preventing and treating fire ants.

The biological preparation for preventing and controlling fire ants by using the lilium fungus strain comprises the steps of strain activation and propagation, preparation of spore suspension and biocontrol effect measurement, and specifically comprises the following steps:

A. strain activation and propagation: inoculating the lilium fungus strain to an activation and propagation culture medium, and culturing for 10-20 days at 20-30 ℃ to obtain an activation and propagation spore-producing strain; the activation and propagation culture medium is a PDA culture medium;

B. preparation of spore suspension: inoculating activated and expanded spore-producing strains to a PDA culture medium, culturing for 10-20 days at a constant temperature of 20-30 ℃, washing spores in a culture dish by using a sterile aqueous solution added with 0.05% Tween-80, pouring bacterial liquid and spores in the culture dish into a cup, oscillating for 30min, filtering by using mirror wiping paper to finally obtain an uncounted spore suspension, placing the suspension under a microscope, counting by using a blood counting plate, recording the number of all spores in 400 cells in the suspension, finally calculating the total spore number of the prepared spore suspension, and diluting to prepare the spore suspension with different concentration gradients;

C. and (3) biocontrol effect determination: uniformly coating insect-preventing escaping powder on the cup mouth of the plastic cup, and uniformly spraying the steamed stuffed bun suspension liquid with different concentration gradients to the solenopsis invicta in the plastic cup by using a small-sized spray can.

The invention is further illustrated by the following specific examples:

example 1

A fungus Strain of the species Purpurena lilacinus (synonym: Paecilomyces: (A))Purpureocillium lilacinum) Acquisition, identification and preservation of PLHHYSFJ 02.

(1) Violet purple spore fungus (synonym: Paecilomyces) strain (A)Purpureocillium lilacinum) Obtaining and identifying PLHHYSFJ 02.

The purple lilac spore fungus (synonym: Paecilomyces) is separated from red imported fire ants, which are collected from the east tricyclic pathway of Kunming city, Panlong district, Yingong district, Dongchuan district and Dehong Dai Jingpo autonomous Ozhou mango city in Yunnan province. And (4) feeding the complete nest with the red imported fire ants in a laboratory.

Cleaning solenopsis invicta with 75% ethanol solution for 5 s, sterilizing the surface of the solenopsis invicta with 0.1% mercuric chloride solution for 2-3 min, slowly showering with sterile water for 3 times, separating the solenopsis invicta with sterilized tweezers, and carefully placing different parts of the solenopsis invicta into culture medium for isolation culture.

Inoculating to a propagation culture medium, and standing and culturing at 25 +/-dark for 9 days until bacterial colonies grow out. The propagation culture medium is a PDA culture medium. After the bacterial colony grows out, selecting the strain with good growth vigor to a preservation culture medium, and preserving and culturing the strain, wherein the preservation culture medium is a PDA culture medium.

The PDA solid medium components are preferably as follows in g/L: 200g of potato, 20g of glucose, 20g of agar and natural pH.

The isolated strain PLHHYSFJ02 was further characterized morphologically and molecularly by biological property observation, and the results of the experiment were recorded as follows.

A. Morphological characteristics: culturing in PDA culture medium at 25 deg.C + -7 d, colony diameter is 5cm, spore stalk is upright, and bottle stalk component with dense arrangement is branched. Small stems are bottle-shaped or slightly enlarged, and are wheel-shaped branches. A slender neck is formed by the gradual tapering of the base to the top. Conidia cross-growing in an oval shape. The conidium is in a single spore chain shape.

B. The culture characteristics are as follows: the characteristics of the colonies cultured on a PDA culture medium at 25 +/-10 days are as follows: slow growth, sheepskin-like, pink-purple, light yellow on the reverse side. White colonies in the initial stage of the PDA culture medium gradually turn pink, the edges of mycelia are in a plush shape, and the mycelia are thin.

C. Stability of the strain: the growth temperature range of the strain is 15-35 ℃, the suitable growth temperature is 20-30 ℃, the growth pH value is 5.5-7.5, and the optimum pH value is 6.5-7.

D. 5.8S R DNA sequence analysis: performing DNA sequence determination on the strain, taking the total DNA of the strain PLHHYSFJ02 as a template, and performing PCR amplification on a 5.8 sr DNA sequence of the strain under the guide of primers ITS1 (5 '-TCCGTAGGTGAACCTGCGG 3') and ITS4 (5 '-TCCGTAGGTGAACCTGCGG 3'), wherein the PCR reaction system is as follows: 2 XTaq Master Mix 25. mu.L, deionized water 20. mu.L, primer ITS 11.5. mu.L, primer ITS 41.5. mu.L, DNA 2. mu.L, total 50 ul. PCR reaction conditions of a, 94 ℃ for 3 min; b. 30 s at 94 ℃, 40s at 56 ℃, 50s at 72 ℃ and 35 cycles; c. preserving at 72 deg.C for 10 min and 4 deg.C.

DNA sequence analysis: sending the PCR reaction product to a biological company for sequencing to obtain an ITS sequence, performing recheck, comparing in the National Center for Biotechnology Information (NCBI), and comparing the results to show that the strain PLHHYSFJ02 and the purple spore (synonym: Paecilomyces) fungus strain (A)Purpureocillium lilacinum) The similarity of the 5.8S r DNA sequence reaches 99%. Identifying the strain PLHHYSFJ02 as a fungus Paecilomyces lilacinus (synonym: Paecilomyces) of the genus P.lilacinus by sequence alignment and morphological characteristicsPurpureocillium lilacinum). The 5.8S r DNA sequence of the strain PLHHYSFJ02 is as follows:

(2) violet purple spore fungus (synonym: Paecilomyces) strain (A)Purpureocillium lilacinum) Deposit of PLHHYSFJ 02.

From the above identification results, it was confirmed that the strain PLHHYSFJ02, which is a kind of fungi belonging to the genus Porphyra (synonyms: Paecilomyces), was named PLHHYSFJ02 and was deposited in the China General Microbiological Culture Collection Center (China General Microbiological Culture Collection Center, CGMCC, Inc. having the address of CGMCC No. 3, Minn institute of microbiology, Soy code 100080) on 28.12.2018 in the General Microbiological Culture Collection Center of China Committee for cultivation management of microorganisms. The preservation number is CGMCC No: 17067.

Example 2

A strain of lilium purple spore (synonym: Paecilomyces) fungus (A), (B) and (C)Purpureocillium lilacinum) PLHHYSFJ02 is used to prepare biocontrol microbial inoculum.

(1) And (4) preparing a spore suspension.

Firstly, the purple lilac spore fungus (synonym: Paecilomyces) strain is prepared (Purpureocillium lilacinum) The PLHHYSFJ02 strain is inoculated on a common PDA culture medium and cultured in a 25 ℃ plus or minus incubator for 15d at constant temperature.

Sterilized sterile water was then added with 0.05% Tween-80.

The spores in the petri dish were rinsed with sterile aqueous solution.

And (3) pouring the bacterial liquid and the spores in the culture dish into a cup, continuously shaking for 30min, and filtering by using a piece of lens wiping paper to finally obtain an countless spore suspension.

The hemocytometer was removed, placed under a microscope, and the number of all spores in the 400-cell interior was recorded.

Finally, the total spore number of the prepared spore suspension was calculated and diluted to 1.0X 10⁶each.mL⁻¹A spore suspension.

(2) And (5) result approval and verification.

The slide was dropped with a spore suspension of undiluted concentration and a spore suspension after dilution. The number of spores on the slide glass of the spore suspension at the undiluted concentration and the spore suspension after dilution was observed under a microscope to determine whether the difference was significant.

Example 3

A fungus Strain of the species Purpurena lilacinus (synonym: Paecilomyces: (A))Purpureocillium lilacinum) PLHHYSFJ02 is used to prepare biocontrol microbial inoculum.

(1) And (4) preparing a spore suspension.

Firstly, the purple lilac spore fungus (synonym: Paecilomyces) strain is prepared (Purpureocillium lilacinum) The PLHHYSFJ02 strain is inoculated on a common PDA culture medium and cultured in an incubator at 26 ℃ for 15 days at constant temperature.

Sterilized sterile water was then added with 0.05% Tween-80.

The spores in the petri dish were rinsed with sterile aqueous solution.

Finally, the total spore number of the prepared spore suspension was calculated and diluted to 1.0X 10⁷each.mL⁻¹A spore suspension.

(2) And (5) result approval and verification.

Example 4

The fungus strain(s) of the lilium purple spore (synonym: Paecilomyces) is adopted (I)Purpureocillium lilacinum) And (3) carrying out biological control effect measurement on the PLHHYSFJ 02.

Firstly, knocking a nest of the red fire ants, attracting the red fire ants to attack by using a sterilized cotton ball, putting the cotton ball and the red fire ants bitten by the cotton ball into a plastic cup with the bottom of 3 cm together, selecting the red fire ants with the same size as each other, keeping the red fire ants in the cup, and counting, wherein each cup of the red fire ants is tested by 30 insects.

And uniformly coating insect-preventing escaping powder on the cup mouth. Preventing the red imported fire ants from escaping.

Uniformly spraying 1.0 × 10 pieces of fire ants in the plastic cup with a small-sized spray can⁶each.mL⁻¹Adding a cotton ball dropwise added with 15% sterile honey water into the spore suspension to supplement nutrition for Solenopsis invicta. A certain amount of sterile water is injected into the cotton ball in the plastic cup to achieve the purpose of moisturizing, and the plastic cup cover is sealed and is pricked with a plurality of small holes for ventilation.

A sterile aqueous solution to which 0.05% Tween-80 was added was used as a control.

And (3) transferring the two materials together to an incubator for constant-temperature culture for 10d, opening the incubator every 24 hours, taking out the plastic cup, recording the number of dead workers, picking out the dead workers for moisturizing culture, and checking whether fungi grow.

Comparing the reasons of the death of the ergate of the solenopsis invicta. The cumulative mortality rate of workers is carefully calculated. The experiment was repeated three times.

Example 5

The fungus strain (A) is a Paecilomyces (synonym: Paecilomyces)Purpureocillium lilacinum) And (3) carrying out biological control effect measurement on the PLHHYSFJ 02.

Uniformly spraying 1.0 × 10 red fire ants in a plastic cup with a small-sized watering can⁷each.mL⁻¹Adding a cotton ball dropwise added with 15% sterile honey water into the spore suspension to supplement nutrition for Solenopsis invicta. A certain amount of sterile water is injected into the cotton ball in the plastic cup to achieve the purpose of moisturizing, and the plastic cup cover is sealed and is pricked with a plurality of small holes for ventilation.

Example 6

The fungus strain(s) of the lilium purple spore (synonym: Paecilomyces) is adopted (I)Purpureocillium lilacinum) PLHHYSFJ02 was used for real soil environmental biocontrol.

1. A method for preparing conidia according to the procedure (1) of example 2 described above, comprising inoculating a strain of the fungus Viola lilacinus (synonym: Paecilomyces), (I)Purpureocillium lilacinum) PLHHYSFJ02 conidia were added to a 0.05% tween-80 solution, and the experimental and control groups were set at the following concentrations or methods:

1.0×10⁶each.mL⁻¹Spore suspension,1.0×10⁷each.mL⁻¹Spore suspension, blank control, clear water.

Each 2 ant nests are treated, the ant nests are knocked, a large number of red fire ants are induced to climb out of the surfaces of the ant nests, and violet spore fungus strains (synonyms: Paecilomyces) with different concentrations are respectively sprayed (A) (B)Purpureocillium lilacinum) Conidia suspension of PLHHYSFJ02, the formicary was visually inspected for complete wet-out and spraying was stopped.

And after the biological control treatment is carried out for 10 days, digging an ant nest, checking and counting the number of dead red fire ants.

Example 7

The fungus strain(s) of the lilium purple spore (synonym: Paecilomyces) is adopted (I)Purpureocillium lilacinum) Analysis of data on the biological control effect of PLHHYSFJ 02.

In a laboratory, carrying out spray treatment on the solenopsis invicta in spore suspension liquid with different concentrations, and continuously recording the death rate of the solenopsis invicta for 10 days; knocking the ant nest to induce a large number of red fire ants to climb out of the surface of the ant nest, and spraying different concentrations of lilac violet fungus strains (synonyms: Paecilomyces) respectivelyPurpureocillium lilacinum) PLHHYSFJ02 conidia suspensions were analyzed using SPSS 22.0 software to calculate lethality at each concentration. The experimental data were processed using SPSS 22.0 software for differential significance analysis.

The calculation formula is as follows:

mortality (%). mortality vs. number of dead insects/number of insects before treatment X100%

Corrected mortality (%) - (treatment mortality-control mortality)/(1-control mortality) × 100%

The results show that spray treatment of 10 days later for the fungus Paecilomyces (A)Purpureocillium lilacinum) The conidia of the PLHHYSFJ02 strain has the toxicity effect on the red imported fire ants:

1.0×10⁶each.mL⁻¹Spore suspension, 1.0X 10⁷each.mL⁻¹The spore suspension concentrations corresponded to a corrected mortality of 67.05% and 70.55%, respectively. As shown in table 1. The results show that the fungus strains of the genus Arisaema (synonym: Paecilomyces) ((R))Purpureocillium lilacinum) PLHHYSFJ02 pairsThe lethal effect of red fire ants is very rapid.

TABLE 1 determination of virulence of Solenopsis invicta spore suspensions of PLHHYSFJ02 strain at different concentrations

Note that different letter representations after the data differed significantly at the 0.05 level

Regression analysis of conidium concentration and solenopsis invicta corrected mortality was performed using SPSS 22.0 software. The regression equation is 11.125X + 2.143.

The concentration X is converted using a base 10 logarithm.

The results show that after 10 days of spray treatment, the fungus strain (synonym: Paecilomyces) of the genus lilac (Paecilomyces)Purpureocillium lilacinum) The PLHHYSFJ02 strain conidia has toxicity effect on the whole ant nest of the red imported fire ants:

the field drug effect toxicity of the strain to the solenopsis invicta is 1.0 multiplied by 10⁶each.mL⁻¹Spore suspension, 1.0X 10⁷each.mL⁻¹The spore suspension concentrations correspond to 311 and 389 solenopsis invicta deaths, respectively. The results show that the strain of Paecilomyces fungus: (Purpureocillium lilacinum) PLHHYSFJ02 was able to cause a concentrated mass of deaths to solenopsis invicta in the nest and in the soil. The death speed is high.

Claims

1. The lilac purple fungus strain is characterized in that the lilac purple fungus strain is classified and namedPurpureocillium lilacinumThe preservation unit is as follows: china general microbiological culture Collection center (CGMCC), preservation date: 28/12/2018, accession number: CGMCC No.17067, wherein the lilac purple fungus belongs to the fungus kingdom, Eumycota, fungi imperfecti, order hyphomycetales, family hyphomycetaceae, genus lilac purple.

2. Use of a fungus strain of the genus violaxanthus according to claim 1, characterized in that it is used for the preparation of a biological preparation for the biological control of fire ants.

3. The use of a fungus strain of the genus violaxanthus according to claim 2, wherein the preparation of a biological control fire ant biological agent from a fungus strain of the genus violaxanthus comprises the steps of strain activation and propagation, preparation of a spore suspension, and biocontrol effect measurement, and specifically comprises:

A. strain activation and propagation: inoculating the lilium fungus strain to an activation and propagation culture medium, and culturing for 10-20 days at 20-30 ℃ to obtain an activation and propagation spore-producing strain; the activation and multiplication culture medium is a PDA culture medium;

B. preparation of spore suspension: inoculating activated and expanded spore-producing strains to a PDA culture medium, culturing for 10-20 days at a constant temperature of 20-30 ℃, washing spores in a culture dish by using a sterile aqueous solution added with 0.05% Tween-80, pouring bacterial liquid and spores in the culture dish into a cup, continuously shaking for 30min, filtering by using mirror wiping paper to finally obtain an uncounted spore suspension, placing the spore suspension under a microscope, counting by using a blood counting plate, recording the number of all spores in 400 cells in the cup, finally calculating the total spore number of the prepared spore suspension, and diluting to prepare the spore suspension with different concentration gradients;