CN109355208B

CN109355208B - A kind of high pathogenicity biocontrol bacteria Cordyceps javanica and its application

Info

Publication number: CN109355208B
Application number: CN201811505030.2A
Authority: CN
Inventors: 邱宝利; 欧达; 阿里·肖卡特; 张利荷
Original assignee: South China Agricultural University
Current assignee: South China Agricultural University
Priority date: 2018-12-10
Filing date: 2018-12-10
Publication date: 2020-04-14
Anticipated expiration: 2038-12-10
Also published as: CN109355208A

Abstract

The invention discloses Cordyceps javanica with high pathogenicity biocontrol bacteria and its application. The present invention finds that Cordyceps javanica ( Cordyceps javanica ) has a strong infestation and insecticidal effect on Bemisia tabaci and Citrus psyllids, and a highly pathogenic Cordyceps javanica strain GZQ-1 was screened out in August 2018. It was deposited in the Guangdong Provincial Microbial Culture Collection Center on May 20, and the strain preservation number: GDMCC No: 60437. This strain is an entomopathogenic fungus, which can be used as a living biological pesticide, and has a very good effect in the biological control of Bemisia tabaci and Citrus psyllid, as well as in the control of diseases caused by Bemisia tabaci and Citrus psyllid-borne pathogens. Strong application potential.

Description

High-pathogenicity biocontrol bacterium Java cordyceps sinensis and application thereof

Technical Field

The invention belongs to the technical field of biological control. More particularly, relates to a high-pathogenicity biocontrol bacterium Java cordyceps and application thereof.

Background

Insect pests refer to the damage caused by harmful insects to the growth of plants. For example, Bemisia tabaci (benisia tabaci (genodus)) tomato, cucumber, pepper and other vegetables and cotton and other crops, Bemisia tabaci directly pricks plant juice to cause plant weakness, nymphs and adults can also secrete honeydew to induce the generation of sooty mould, and when the density is high, leaves are black, thus seriously affecting photosynthesis. In addition, the bemisia tabaci can also transmit more than 70 virus diseases on 30 crops, and different biotypes transmit different viruses, so that the caused harm is not easily seen. Further, for example, diaphorina citri (diaphorinaciti kuwayama) is an important vector insect for citrus greening disease, and represents a great threat to the healthy development of the citrus industry in our country and even in the world. The damaged tender shoot of the host can be withered, deformed and the like. The psyllids also secrete white honeydew and adhere to branches and leaves, which can cause the occurrence of soot diseases. What is worse, the psyllids feed, lay eggs and reproduce on the citrus greening disease plants, so that a large amount of bacteria-carrying imagoes can be generated, and the imagoes can spread the greening disease by transferring into new harmful plants. The main harmful crops of diaphorina citri are rutaceae plants, the heaviest of citrus plants, namely wampee, murraya paniculata and citric acid.

At present, the control of insect pests is mainly based on traditional chemical control. However, most of pesticides are extremely toxic and are forbidden by China, and a series of problems of massive death of natural enemy insects, loss of biological diversity, generation of drug resistance in different degrees, pollution to the ecological environment and the like are caused by long-term and massive use of chemical pesticides, and the problem of overproof pesticide residues also sometimes occurs. In the face of such passive situation, research and application of non-chemical means for pest control have been urgent problems.

Biological control becomes the most effective and promising control means for pests due to the advantages of green, environmental protection, persistent effect and the like. Biological control is a control technology for controlling harmful biological populations by using beneficial organisms and products thereof, and mainly inclines the dynamic balance among organisms towards the direction beneficial to agricultural production by using interdependent and mutually restricted food chains among the organisms. Therefore, the search for effective biological control products and application techniques is one of the main research directions for sustainable pest control in the future.

Disclosure of Invention

The invention aims to solve the technical problems of overcoming the defects and technical defects of insect pest control methods such as bemisia tabaci and diaphorina citri and providing a biocontrol bacterium with high pathogenicity, namely Cordyceps javanicus (cordyces japonica). The strain is an entomopathogenic fungus, and can be used as a living biological pesticide with high pathogenicity for preventing and treating bemisia tabaci and diaphorina citri.

The invention aims to provide a high-pathogenicity biocontrol bacterium Java cordyceps.

The invention also aims to provide application of the cordyceps javanicus in preventing and treating bemisia tabaci and diaphorina citri.

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

the research of the invention finds that the Java cordyceps sinensis (Cordycepsjavanica) has strong infection insecticidal effect on bemisia tabaci and diaphorina citri, a Java cordyceps sinensis strain GZQ-1 with high pathogenicity is screened, and is preserved in Guangdong province microorganism strain preservation center in 2018, 20 days, with the strain preservation number: GDMCC No: 60437, the preservation address is No. 59 building 5 of No. 100 Dazhong Jie-Lu-100 Guangzhou city.

Therefore, the following applications should be within the scope of the present invention:

application of Cordyceps javanicus in preventing and treating Bemisia tabaci and/or diaphorina citri is provided.

Application of Cordyceps javanicus in preparing pesticide for preventing and treating bemisia tabaci and/or diaphorina citri is provided.

Application of Cordyceps javanicus in preventing and treating diseases caused by Bemisia tabaci and/or diaphorina citri or preparing medicines for preventing and treating diseases is provided.

In addition, a drug containing the cordyceps javanicus and capable of preventing and treating bemisia tabaci and/or diaphorina citri and a drug containing the cordyceps javanicus and capable of preventing and treating diseases caused by the bemisia tabaci and/or diaphorina citri are also within the protection scope of the invention.

Preferably, the Java cordyceps is the above Java cordyceps strain GZQ-1.

Preferably, the diseases caused by the bemisia tabaci and/or the diaphorina citri refer to diseases caused by the bemisia tabaci and/or the diaphorina citri as transmission vectors.

Specifically, the diseases caused by bemisia tabaci as a transmission medium comprise geminivirus diseases such as yellow leaf curl disease, and the diseases caused by diaphorina citri as a transmission medium comprise citrus yellow dragon disease.

The invention has the following beneficial effects:

the invention obtains a Java cordyceps sinensis strain GZQ-1 with high pathogenicity to bemisia tabaci and diaphorina citri through screening, and long-term infection biology and indoor bioassay show that the strain has very strong infection insecticidal effect on the bemisia tabaci and the diaphorina citri, and the strain is an entomopathogenic fungus, can be used as a living biological pesticide and has very strong application potential in biological control of the bemisia tabaci and the diaphorina citri.

Drawings

FIG. 1 shows Cordyceps javanicus spore suspension (1 × 10) with different concentrations³，1×10⁴，1×10⁵，1×10⁶，1×10⁷Conidia/ml) mortality of diaphorina citri at different developmental stages. Data are mean ± sem of triplicates.

FIG. 2 is a morphological diagram of Java Cordyceps strain GZQ-1.

FIG. 3 shows molecular identification phylogenetic tree of Cordyceps javanicus strain GZQ-1.

FIG. 4 shows the spore suspension (1 × 10) of Cordyceps javanicus strain GZQ-1, Cordyceps fumosoroseus strain IF010 and Metarrhizium anisopliae strain CNGD7 infected with adult diaphorina citri under half field conditions⁷Spore/ml). Data are mean ± sem of triplicates.

FIG. 5 is a comparison of the pathogenicity of Cordyceps javanicus and Cordyceps fumosa-rosei to Bemisia tabaci at different ages; note: the same letter after the end of the same column in the figure indicates that the difference is not significant (P > 0.05).

FIG. 6 is the mortality (%) of Bemisia tabaci for each treatment under field conditions; note: the same letter above different columns indicates that the differences between different treatments were not significant (P > 0.05Duncan test).

Detailed Description

The invention is further described with reference to the drawings and the following detailed description, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

Example 1 isolation and identification of Cordyceps javanicus Strain GZQ-1

1. Sources of materials

(1) Sample preparation: cordyceps javanicus is continuously preserved by biological control engineering research center of education department of university of agriculture in south China, and the strain preservation sample is separated by unit cell to obtain purified strain.

(2) Potato dextrose agar medium (PDA): cutting 200g peeled potato into small pieces, adding 1L water, boiling for 20min, filtering with gauze: adding 20g of glucose and 18-20 g of agar while the mixture is hot, stirring to dissolve and mix uniformly, fixing the volume to a conical flask, and sterilizing in an autoclave (121 ℃, 30min) for 30 min.

(3) Sterile operating conditions: all the utensils and appliances need to be sterilized in autoclave (121 ℃, 30min), and the operations of inoculation and the like are all carried out in a clean bench.

(4) The culture conditions are as follows: culturing in 25 deg.C light (12L: 12D) incubator, transferring to PDA inclined plane after colony formation, and storing in 4 said refrigerators.

2. Isolation and purification of the strains

(1) Separation of

The strain is collected by inventor Ouda in 2017 in 6 months from Murraya koenigii leaves parasitized on Murraya koenigii leaf of Changgang mountain No. 2 of the university of agricultural industry in south China, and the method comprises the following steps: and (3) disinfecting the surface of the sample by using a 5% sodium hypochlorite solution, washing the disinfected sample in sterilized water for three times, putting the sample into a PDA flat plate, inverting the sample into a thermostat at 25 ℃ for culture, transferring the sample into a PDA inclined plane after bacterial colonies are formed, and then transferring the sample into a refrigerator at 4 ℃ for storage.

(2) Purification of

Culturing the separated strain on PDA culture medium for 10 days, and collecting conidium to obtain 1 × 10 conidium³Conidium suspension of spores/ml, the suspension was dropped on a glass slide with a cover glass, observed under a biological microscope, a slide with only one conidium in one drop was inserted on a medium, and cultured in an incubator to obtain an isolate.

3. Method for screening isolated strain of Cordyceps javanicus

Entomogenous fungi have diversity in genetics, ecology, biology and the like. The screening and obtaining of high-yield and high-quality strains are the first premise for obtaining better control effect. The strain screening mainly considers 3 indexes of sporulation quantity, colony growth rate and pathogenicity respectively. The invention selects excellent strains based on the indexes.

(1) Treatment of test strains

The purified Cordyceps javanicus strain was cultured in a constant temperature chamber (12L: 12D) at 25 ℃ on a PDA plate.

(2) Test insects and host plants

The diaphorina citri is a subculture population on murraya paniculata in a net room of the research center of biological control engineering of education department. Murraya paniculata Murrayapaniculata L.A large number of Murraya paniculata seedlings are purchased in great wall of Guangzhou province and planted in a net room of the research center of biological control engineering of the education department of agriculture university in south China.

(3) Determination of colony growth rate and spore yield

Preparing 1X 10 of Java cordyceps strain⁶1ml of conidium suspension with the concentration of spores/ml is dripped into a PDA plate with the diameter of 9cm, a triangular glass rod is used for coating uniformly, a puncher with the diameter of 13mm is used for taking fresh colonies after 7d hyphae grow out, then the fresh colonies are inoculated on a PDA culture medium for culture, 5 times of repetition is carried out, the diameter of the colonies is measured and recorded after 10 days, and conidia are collected on the 10 th day and the spore yield is measured by a blood counter.

The colony growth rate and sporulation quantity of the isolated strain GZQ-1 of Cordyceps javanicus are shown in Table 1.

TABLE 1 colony diameter expansion and spore yield (10d) of isolated strain of Cordyceps javanicus

Bacterial strains	Diameter expansion SE (mm)	Sporulation yield (conidia/ml)
			GZQ-1	42.3±1.86	2.26×10⁸

(4) Pathogenicity of isolated strains to diaphorina citri of all ages

Inoculating the isolated strain on PDA plate, culturing for 10 days, collecting conidia with 0.03% Tween-80 sterile water, and making into 1 × 10³、1×10⁴、1×10⁵、1×10⁶、1×10⁷Spore/ml spore suspension, spraying to leaf surface of folium Et cacumen Murrayae containing Mandarin orange psyllid to form water drop, and leaving water drop on each budNymphs of 1-2, 3-4, 5 and adults are 10 each, and 0.03% Tween-80 sterile water is sprayed in contrast, and 3 repetitions are set for each treatment. The experimental plants were placed at 26 ± 1 ℃, L: d is 12: 12, and maintaining humidity above 90%, and recording the mortality rate every 2 days for 7 days.

The results of the pathogenicity study of the isolated strains on diaphorina citri at each age are shown in fig. 1. Bioassay results show that the corrected mortality rates of the GZQ-1 strain on 1-2 th-instar nymphs, 3-4 th-instar nymphs, 5 th-instar nymphs and adults of diaphorina citri are 91.7 +/-2.36%, 88.3 +/-4.33%, 73.3 +/-3.32% and 72.2 +/-2.94% respectively at 7 days after infection.

(5) Screening results of isolated strain of Cordyceps javanicus

When screening excellent isolates, the sporulation quantity, the pathogenicity and the colony growth rate of the strains are taken as important reference indexes. In the invention, compared with the three judgment standards, the strain GZQ-1 has excellent properties, strong pathogenicity and high sporulation quantity, and the strain GZQ-1 has high pathogenicity to diaphorina citri at different ages by correcting the death rate (figure 1). By comprehensively comparing various factors, the strain GZQ-1 has high pathogenicity on diaphorina citri at all ages.

4. Identification of isolated strain of Java cordyceps

The strain belongs to Hypocreales and Cordyceps after morphological and molecular identification. Conidia of the strain have straight stems, are in a long-egg type and are connected into chains (figures 2 and 3). The strain is named as a Cordyceps javanicus (Cordycepsjavanica) strain GZQ-1, and is preserved in Guangdong province microorganism strain preservation center in 2018, 8 and 20 days, wherein the strain preservation number is as follows: GDMCC No: 60437, the preservation address is No. 59 building 5 of No. 100 Dazhong Jie-Lu-100 Guangzhou city.

Example 2 pathogenicity determination of Cordyceps javanicus GZQ-1 Strain to Citrus psyllids of different ages

1. Bioassay is one of effective means for detecting the lethal degree and the lethal rate of entomogenous fungi on target pests, and can provide an important reference basis for comprehensively evaluating the biological control potential of the entomogenous fungi. In the research, the pathogenicity of the Java cordyceps GZQ-1 strain to diaphorina citri at different ages is measured, so that the optimal age and concentration of the strain to diaphorina citri lethal are screened out.

2. Test insects and host plants: the method comprises the steps of feeding adult diaphorina citri in a net room of a biological control engineering research center of education department, inoculating the adult diaphorina citri on clean and healthy murraya paniculata, inoculating 20 pairs of adults to each murraya paniculata, covering each pot of murraya paniculata with a net cover made of a PVC (polyvinyl chloride) film, removing adults after the adults lay eggs for 24 hours, and performing tests when nymphs of the diaphorina citri develop to different ages. Murraya paniculata Murrayapaniculata L is potted Murraya paniculata planted in laboratories of the research center of biological control engineering of the education department, and is used for tests when the height of seedlings is 30-40 cm.

3. Treatment of test strains

Culturing the GZQ-1 strain of Cordyceps javanicus obtained by purification treatment in a constant temperature box (12L: 12D) at 25 deg.C for 10D with PDA plate, selecting well-grown colony, pouring 20ml of 0.03% Tween-80 sterile water, scraping hypha and spore of fungus with inoculating needle, pouring the bacterial liquid into beaker, stirring with magnetic stirrer for 30min, filtering with two layers of medical gauze after spore is completely scattered to obtain pure spore suspension, discarding culture medium residue and hypha on the gauze, counting spore concentration of mother liquid with 40 times objective lens and blood count plate, and diluting to 1 × 10³、1×10⁴、1×10⁵、1×10⁶And 1X 10⁷Spores/ml 5 samples of 20ml each were used.

4. Pathogenicity of isolated strains to diaphorina citri of all ages

Preparing 1 × 10 of the isolated strain³、1×10⁴、1×10⁵、1×10⁶、1×10⁷Spore/ml spore suspension is sprayed to leaf surfaces of murraya jasminorage tender shoots connected with diaphorina citri to form water drops, each tender shoot is left with 10 heads of nymphs of 1-2 years, nymphs of 3-4 years, nymphs of 5 years and adults, 0.03% of tween-80 sterile water is sprayed in contrast, and each treatment is set to be 3 times. The experimental plants were placed at 26 ± 1 ℃, L: d is 12: 12, and maintaining the humidity above 90% every 2 daysThe mortality was recorded for a total of 7 days.

5. Cumulative mortality of Isaria javanicanicus to diaphorina citri nymphs

The results showed that (FIG. 1, Table 2, Table 3), the number of cells was 1X 10³At the concentration of spores/ml, the death rate of nymphs of diaphorina citri at 1-2, 3-4 and 5 years is only 30.6%, 25.9% and 20.0%, respectively. At 1X 10⁴Under the concentration of spores/ml, the lethality of isaria fumosorosea to nymphs of diaphorina citri at various ages is between 27.6 and 40.4 percent. Similarly, with the increase of the concentration, the lethal effect of the Cordyceps javanicus on nymphs of diaphorina citri at each age is higher and higher, and is 1 × 10⁷Under the condition of spores/ml, the lethality rate to 1-2-year nymphs reaches 90.9%, which shows that the Java cordyceps has very high control effect on the diaphorina citri low-age nymphs and the lethality rate to 5-year nymphs also reaches 69.8%. At 1X 10⁶And 1X 10⁷Under the concentration of spores/ml, the lethality rate of isaria fumosorosea to old nymphs of diaphorina citri is obviously lower than that of the low-age nymphs, which shows that the infection effect of isaria fumosorosea to low-age nymphs is good, and the low-age nymphs, particularly 1-2 years, are the best period for preventing and treating.

TABLE 2 cumulative mortality of Cordyceps javanicus to diaphorina citri nymphs at different concentrations

Note: data in the table indicate mean ± sem, and the same letter in the same column indicates no significant difference between treatments (P > 0.05Duncan test).

TABLE 3 cumulative mortality of Cordyceps javanica to diaphorina citri adults 7d

6. Lethal concentration of Java cordyceps sinensis on diaphorina citri adults

Regression equations and parameters of virulence of Cordyceps javanicus strains to diaphorina citri at different developmental stages were obtained by data processing analysis (Table 4). LC of diaphorina citri₅₀Values increased with increasing age of diaphorina citri.

TABLE 4 LC of Cordyceps javanica against diaphorina citri at different stages of development₅₀Regression equation and parameters

7. Time effect of Cordyceps javanicus on diaphorina citri at different developmental stages

The median lethal time of Cordyceps javanicus on diaphorina citri at different stages of development obtained by data processing and analysis is shown in Table 5. LT of diaphorina citri₅₀Values increased with increasing age of diaphorina citri.

TABLE 5 LT of Cordyceps javanica against diaphorina citri at different stages of development₅₀Regression equation and parameters

Age of age	Regression equation of pathogenicity	LT₅₀And its 95% confidence interval (sky)	R²
				Age 1-2	Y＝0.549X-2.335	4.25(3.87～4.64)	0.950
Age 3-4	Y＝0.466X-2.101	4.51(4.08～4.96)	0.976
				Age 5	Y＝0.449X-2.322	5.17(4.73～5.70)	0.981
Imago	Y＝0.486X-2.668	5.49(5.09～5.96)	0.943

Example 3 field control of adult diaphorina citri by Cordyceps javanicus GZQ-1 Strain

Under field conditions, 1 × 10 of Cordyceps javanicus GZQ-1 was used⁷Spores/ml spore suspension treated adult diaphorina citri with cordyces fumosorosea strain IF010 and Metarrhizium anisopliae strain CNGD7 as controls.

The cumulative survival rate of 13d is shown in figure 3, the lethality rate is higher and higher with the increase of the concentration of the spores of the java cordyceps, and the infection rate of the java cordyceps strain GZQ-1 is obviously higher than that of the rhodochrous cordyceps strain IF010 and the Metarrhizium anisopliae strain CNGD7(P is less than 0.05) 7 days after infection.

Example 4 virulence determination of Cordyceps javanicus GZQ-1 Strain on Bemisia tabaci

1 Material

A test insect source: the Bemisia tabaci B biotype population is initially collected in 2015 on a education practice farm of southern China university of agriculture and is then accessed into a laboratory of the engineering research center of the department of biological control education. Cotton plants are used as hosts for subculture propagation, and more than 10 generations are propagated for experiments.

Test entomopathogenic strains: cordyceps javanicus (Cordyceps javanica) strain GZQ-1 and control strain Cordyceps fumosorosea (Cordyceps fumosorosea) strain IF-BDC01 (publication No: CN106065392A) are both preserved in Guangdong province microorganism strain preservation center, and the preservation numbers of the strains are respectively: GDMCC 60437 and GDMCC 60011, and was subcultured by the engineering research center of the department of biological control education of south china agricultural university. In the test, the strain was transferred to a new SDAY/4 medium and used for the test after two weeks of culture.

2. Selection of optimum treating age of Euglena chinensis Cordyceps and fumaria rose to Bemisia tabaci

The inoculated strain is prepared with sterile water of 1 percent of Tween-80 with the concentration of 1 multiplied by 10⁸mL^-1The conidium suspension is prepared for later use after the conidium activity is determined. Selecting cotton leaf with nymphs of bemisia tabaci at 1, 2, 3 and 4 ages, respectively, soaking in the spore suspension for 15s, 50 nymphs per leaf, repeating the treatment for 5 times, and using 1% Tween-80 as a control. Placing cotton leaf in agar (10 g.L)^-1) The culture dish is sealed by a perforated preservative film, the culture dish is placed in an artificial climate box (the temperature is 26-27 ℃, RH 75-80% is used for culture, 14L:10D), and the death rate of 7 days is continuously recorded.

Adult experiment, soaking clean cotton leaf in spore suspension for 15s, air drying the bacterial liquid, and placing the cotton leaf in agar (10 g.L)^-1) The adult Bemisia tabaci (male and female) was inoculated into the culture dish, sealed with a perforated wrap film, and 1% Tween-80 was used as a control. 50 adult whitefly per dish, each treatment was repeated 5 times. The culture conditions were the same as in the previous step, and the mortality rate was recorded for 7 days by continuous observation.

The results show that the same concentration (1X 10) is used⁸mL^-1) The age of Bemisia tabaci treated with Cordyceps fumosoroseus and Cordyceps javanicus was shown in FIG. 5, and the cumulative mortality on day 7 was shown. It can be seen that both the Java cordyceps and the rose-color cordyceps can infect bemisia tabaci in each age, and especially, the death rate of the nymphs in two ages is highest, and the nymphs in two ages are respectively91.28% and 76.85%; and the fatality rate of the Java cordyceps sinensis to nymphs and adults of bemisia tabaci at each age is superior to that of the rose-smoky cordyceps sinensis.

3. Pathogenicity of different concentrations of Cordyceps javanicus and Cordyceps fumosa roseus in optimal treatment age of Bemisia tabaci

1 × 10 concentration is prepared by 1% Tween-80 sterile water respectively⁸mL^-1、1×10⁷mL^-1、1×10⁶mL^-1、1×10⁵mL^-1、1×10⁴mL^-1、1×10³mL^-1The conidium suspension is prepared for later use after the conidium activity is determined. Cotton leaves with nymphs of bemisia tabaci at different ages were immersed in spore suspensions at different concentrations for 15s, and 1% tween-80 was used as a control.

The results show that the experimental results (table 6) show that the cumulative corrected mortality of bemisia tabaci gradually increases with the increase of the spore concentration; at 1X 10⁸mL^-1The two strains respectively reach 91.28% and 76.85% of death rate. Even at low concentrations of 1X 10⁴mL^-1In addition, the infectivity of the Java cordyceps sinensis on second-instar nymphs still reaches 54%, and the infectivity of the rose-smoky cordyceps sinensis is only 36%. It can be seen that the pathogenicity of the Cordyceps javanicus on Bemisia tabaci is obviously higher than that of Cordyceps fumosoroseus (P > 0.05).

As can be seen in Table 7, the infection rate of two entomopathogenic fungi to Bemisia tabaci nymphs on days 1d and 2d is very low, the infection rate of Cordyceps javanicus on day three reaches 48.67%, and the lethality rate of Cordyceps fumosoroseus to Bemisia tabaci is lower than 30%. The pathogenicity reached the highest on day 7, 92.68% and 78.12%, respectively. The death rate of second-instar nymphs of the cordyceps rose-smoky cordyceps sinensis is different among the treatment days, the difference between the 6 th day and the 7 th day of the cordyceps javanicus is not obvious, but the difference is different from the rest treatment days.

Through SPSS17.0 software analysis, the lethal medium concentration LC of the Cordyceps javanicus and the Cordyceps fumosoroseus on the second-instar nymphs₅₀Are respectively 9.01X 10³And 9.74X 10⁴Spores/ml (Table 8), lethal Medium LT₅₀The values were 3.051 days and 4.557 days, respectively (Table 9). The experiment shows that the Java cordyceps sinensis kills 50 percent of 2-year nymphs of Bemisia tabaci compared with the rose-color cordyceps sinensisThe concentration is lower and the time is shorter, so that the pathogenic force of the Java cordyceps sinensis to bemisia tabaci is higher than that of the rose smoky cordyceps sinensis.

TABLE 6 pathogenicity of Cordyceps javanicus and Cordyceps fumosa-rosea with different concentrations to Bemisia tabaci second-instar nymphs

TABLE 7 daily mortality of Cordyceps javanicus and Cordyceps fumosoroseus to Bemisia tabaci second-instar nymphs

TABLE 8 lethal middle concentration of Cordyceps javanica and Cordyceps fumosa in the second instar of Bemisia tabaci pathogenicity (LC50)

Bacterial strains	Java cordyceps sinensis	Cordyceps sinensis with color of rose
			Regression equation	Y＝0.421X-1665	Y＝0.33X-1.646
LC50 (spore/ml)	9.01×103	9.74×104
			95% confidence interval (spore/ml)	(5.61×103～1.37×104)	(6.11×104～1.55×105)
χ2	6.356	5.149
			Coefficient of correlation r	0.932	0.972

TABLE 9 lethal time of pathogenicity of two entomopathogenic fungi against Bemisia tabaci two-year-old nymphs (LT50)

Bacterial strains	Java cordyceps sinensis	Cordyceps sinensis with color of rose
			Regression equation	Y＝1.641X-3.384	Y＝3.674X-2.420
LT50(d)	3.051	4.557
			95% confidence interval (d)	2.917～3.185	4.382～4.743
χ2	15.47	12.73
			Coefficient of correlation r	0.663	0.852

Example 5 field control of Cordyceps javanicus GZQ-1 Strain on Bemisia tabaci

Under field conditions, 1 × 10 of Cordyceps javanicus GZQ-1 was used⁷Bemisia tabaci was treated with spore/ml spore suspension, and Cordyceps fumosorosea strain IF010 was used as a control.

The 13d accumulated mortality rate is shown in figure 6, the mortality rate is higher and higher along with the increase of the concentration of the spores of the cordyceps javanicus, and the infection rate of the cordyceps javanicus strain GZQ-1 is obviously higher than that of the cordyceps javanicus strain IF010(P is less than 0.05) after 7 days of infection.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. a highly pathogenic biocontrol bacterium Cordyceps javanica (Cordyceps javanica) bacterial strain GZQ-1 is characterized in that, on August 20, 2018, it was preserved in the Guangdong Provincial Microorganism Culture Collection Center, bacterial strain preservation number: GDMCC No: 60437, the preservation address is 5th Floor, Building 59, No. 100, Xianlie Middle Road, Guangzhou City.

2. The application of Cordyceps javanica in controlling Bemisia tabaci and/or citrus psyllid, wherein the Cordyceps javanica is the Cordyceps javanica strain GZQ-1 according to claim 1.

3. The application of Cordyceps javanica in the preparation of Bemisia tabaci and/or citrus psyllid control drugs, wherein the Cordyceps javanica is the Cordyceps javanica strain GZQ-1 according to claim 1.

4. The application of Cordyceps javanica in preventing and treating diseases caused by Bemisia tabaci and/or citrus psyllid or preparing a control medicine, wherein the Cordyceps javanica is the Cordyceps javanica strain GZQ-1 according to claim 1.

5. The application according to claim 4, wherein the disease caused by Bemisia tabaci and/or Citrus psyllid refers to a disease caused by Bemisia tabaci and/or Citrus Psyllid as a transmission medium.

6 . The application according to claim 4 , wherein the diseases caused by Bemisia tabaci as a transmission medium include yellow leaf curl disease, and the diseases caused by citrus psyllids as a transmission medium include citrus huanglongbing 6 .

7. A medicine for preventing and treating Bemisia tabaci and/or citrus psyllid, characterized in that, comprising the Cordyceps javanica strain GZQ-1 according to claim 1.

8 . A medicine for preventing and treating diseases caused by Bemisia tabaci and/or citrus psyllid, characterized in that it comprises the Cordyceps javanica strain GZQ-1 according to claim 1 .