CN109275667B - Application of Isaria javanicanicus in preventing and treating scale insect - Google Patents

Abstract

The invention discloses application of Isaria javanicanicus in preventing and treating coccid. Hair brushThe first time of the Ming study finds that Isaria javanicus (Isaria javanicus)Isaria javanica) Has good pathogenic prevention and treatment effect on scale insects such as Egyptian icerya and Leptospermum scoparium, can be used as a living biological pesticide with high pathogenicity on scale insects, and has good wide application prospect in the aspect of biological prevention and treatment of scale insects. And Isaria javanicanicus is an entomopathogenic fungus, conidium suspension of Isaria javanicus can directly act on polypide, compared with the existing chemical control medicament, Isaria javanicus has the advantages of high efficiency, greenness, environmental friendliness, strong persistence and difficult generation of drug resistance, has no pollution and residue to the environment, and has good market application prospect when being developed as a biological control agent for preventing and controlling coccid insects.

Description

Application of Isaria javanicanicus in preventing and treating scale insect

Technical Field

The invention belongs to the technical field of biological pest control. More particularly, relates to application of Isaria javanicanicus in preventing and treating Lecanicillium lecanii homoptera insects.

Background

Homoptera are one of the common forestry pests, such as scale insects like Icerya aegyptiaca (Douglas) and Phenacoccus solenopsis Tinsley. The Egyptian Blackia (Icerya aegyptiaca (Douglas)) is an important pest which damages forestry and garden plants, and mainly damages forestry and garden plants such as white orchid, Holland magnolia, large-leaf manglietia and the like in China, and is mainly distributed in places such as Guangdong, Fujian, Zhejiang and Taiwan. As early as the 80's of the 20 th century, the pest was listed as one of the dangerous forestry and gardening pests in Guangzhou areas. The Egyptian Blackermark mainly damages leaf buds, twigs and branches of plants by female adults and nymphs, the female adults and the nymphs gather on the back of leaves or the twigs to absorb plant juice, the quantity of the plant juice is small, the quantity of the plant juice is more than hundreds, and meanwhile, the excreted honeydew induces sooty mold to influence the photosynthesis of the plants and seriously influence the growth vigor of the damaged trees. In recent years, the population number of the Egyptian icerya scale grows year by year, and serious loss is brought to forestry and garden industries.

Aiming at the prevention and control of the icerya ericae and other scale insects, chemical prevention and control are mainly adopted at present, and commonly used chemical agents comprise 2500 times of 24% methomyl soluble liquid, 480g/L of chlorpyrifos emulsifiable concentrate and 1000 times of the liquid. However, the surface of the nymph to adult nymph is covered with wax, and the excessive use of chemical agents causes drug resistance of pests, so that the chemical control effect is not ideal. The large amount of pesticide with broad spectrum not only pollutes environment, but also kills natural enemies, so that the population and the number of the natural enemies are sharply reduced, and the natural control effect is reduced. In the face of such passive situation, research and application of non-chemical prevention and control of Egyptian icerya is an urgent problem to be solved. Therefore, biological control is one of the keys to solve the problem of the damage of the Egyptian icerya.

Biological control most commonly utilizes natural enemies to control the population quantity of pests, and the main natural enemies of Egyptian Blasty scales include ladybug, lacewing and the like. Besides natural enemy insects, the application of entomopathogenic fungi is also a biological control method with wide prospect, and the method has the advantages of high efficiency on pests, environmental friendliness, difficult generation of drug resistance and the like, and is a choice of pathogenic fungi, thus becoming a hotspot of biological control research at home and abroad.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects and shortcomings of the existing prevention and control technology of scale insects such as Egypt icerya purchasi and Hibiscus solenopsis and the like, and provides an important pathogenic fungus of Egypt icerya purchasi insects, namely Isaria javanicus (Isaria javanica), which has high pathogenicity to Egypt icerya purchasi, can be used as a living biological pesticide with high pathogenicity to Homoptera insects such as Egypt icerya purchasi and Hibiscus solenopsis, has the advantages of high efficiency, environmental friendliness, difficulty in generating drug resistance and the like, and has a good application prospect in the aspect of preventing and controlling Egypt icerya purchasi.

The invention aims to provide application of Isaria javanicus in preventing and treating homoptera insects.

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

the pathogenicity research experiment shows that the Isaria javanicus has strong pathogenicity to Lepidoptera insects such as Egyptia Blastus and Lepidium sordidum. Meanwhile, a Isaria javanicus (Isaria japonica) strain IJID003 with high pathogenicity and high sporulation quantity is obtained by screening, and the strain is preserved in the China center for type culture collection in 2018, 10 and 15 months, and the preservation number is CCTCC NO: m2018680.

Isaria javanicus strain IJID003 is isolated from the body of an Egyptian icerya infested in the white orchid in Yuexiu park, Guangzhou, Guangdong province, and has higher pathogenicity and high spore yield compared with Isaria javanicus (Isaria javanica) strain IJID003 isolated from other substrates.

Isaria javanicus strain IJID003 is classified as belonging to the classes Hyphomycetes (Hyphomycetes), Hyphomycetales (Hyphomycetales), Hyphomycetes (Hyphomycetaceae), and Cladosporium (Isaria). The morphological characteristics are as follows: on the PDA plate, the colony is circular, the diameter is 49 mm-55 mm, concentric rings are arranged, and gullies are formed on the culture medium, and the texture is thick downy. The colony had a pale yellow back. The color of the spore layer is light purple gray. The hyphae were transparent and colorless under microscope. The molecular spore stalk is coated with a rotasomal body formed by 2-4 bottle stalks, and the base parts of the bottle stalks are expanded in an oval shape and tapered upwards. Conidia grow on the phialides and form spore chains. The conidia are transparent, smooth and oblong. Conidium size is 4.5 μm (3.1 μm-6.5 μm). times.1.8 (1.5-2 μm).

Therefore, based on the above research results, the following applications should be within the scope of the present invention:

application of Isaria javanicanicus in preventing and treating homopteran insects is provided.

Application of Isaria javanicanicus in preparing homoptera insect biocontrol preparation is provided.

Application of Isaria javanicus IJID003 in preventing and treating homopteran insects is provided.

Application of Isaria javanicus IJID003 in preparing biological control preparation for homoptera insects is provided.

In addition, a homoptera insect biocontrol preparation containing the Isaria javanicus and application of the biocontrol preparation in preventing and controlling homoptera insects are also within the protection scope of the invention.

Wherein preferably, the homoptera insect is an insect of the family Lecanidae or the family Lecanidae.

More preferably, the homoptera insect is an insect of the genus Lecanicillium or the genus Lecanicillium.

More preferably, the homopteran insect is a coccid insect.

More preferably, the scale insect is icerya purchasi or mealybug.

More preferably, the scale insect is Eleutherococcus aegyptii or Eleutherococcus soloniensis.

Preferably, the spore concentration of Isaria javanicus is in the range of 10⁶～10⁸spores/mL.

Preferably, the Isaria javanicanicus is Isaria javanicus strain IJID 003.

The invention has the following beneficial effects:

the invention discovers that Isaria javanicus (Isaria japonica) has good pathogenic prevention and control effect on Homoptera pests such as Elapirus aegypti and Leptococcus solonii, can be used as a living biological pesticide with high pathogenicity on Homoptera pests, and has good wide application prospect in the biological prevention and control aspect of Homoptera pests such as Elapirus solonii and Leptococcus solonii.

Isaria javanicus is an entomopathogenic fungus, conidium suspension of Isaria javanicus can directly act on polypide, and compared with the existing chemical control medicament, Isaria javanicus has the advantages of high efficiency, greenness, environmental friendliness, strong persistence, difficulty in generating drug resistance, no pollution to the environment and no residue.

Meanwhile, the invention also screens out an Isaria javanica (Isaria japonica) strain IJID003 with high pathogenicity to homopteran pests such as Egyptian icerya and Lecanicillium rosae.g., the strain IJID003 has high growth speed, large spore yield and easy preparation, and the strain IJID003 has good market application prospect when being developed as a biocontrol preparation agent for the biological control of homopteran pests such as Egyptian icerya and Lecanicillium rosae.

Drawings

FIG. 1 is a morphological diagram of strain IJID003 grown on PDA medium for 10 days (front view of colony).

FIG. 2 is a diagram of the sporulation structure of strain IJID 003; conidia (A) and conidiophores (B).

FIG. 3 is a phylogenetic tree of strain IJID 003.

FIG. 4 is an infestation of strain IJID003 on Erythium gracilis.

FIG. 5 shows the infection of strain IJID003 on Lecanicillium rosae.

FIG. 6 shows the results of the virulence determination of the female imago of Lecanicillium solenopsis by strain IJID 003.

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 present invention are commercially available.

Example 1 isolation of Isaria javanicus Strain IJID003

The method for separating and obtaining the high-pathogenicity fungus from the Egypt Blastus amabilis which is a natural infection disease collected from the white orchid of the Virginia city of Guangdong province comprises the following steps:

(1) isolation of fungi

Collecting hypha from infected Egyptian Blastus pelykii, inoculating to PDA culture medium, and culturing at 27 + -1 deg.C for 7 days. Picking hyphae from the center of the formed colony, performing purification culture on a PDA culture medium, repeating the purification culture for 3 times, and placing the culture in a refrigerator at 4 ℃ for later use.

(2) Fungi tie-back experiment

Culturing the separated fungus on a PDA plate for 7-15 days, adding 0.02% Tween-80 sterile water to wash off spores after forming bacterial colonies, stirring for 15 minutes on a magnetic stirrer, and adjusting the concentration of the spores to be 1 × 10 by using a blood counting chamber⁷Preparing spore suspension per mL, spraying onto leaf of white orchid with Erypnia pela with small hand sprayer, air drying, placing into culture dish with humidity of 90%, and placing into illumination incubator at 27 + -1 deg.C (L: D ═ 14:10, RH)>90%) and a sterile water-treated group containing 0.02% tween-80 was set as a control. After obvious hypha grows on the surface of the polypide, selecting the hypha and transferring the hypha to a new PDA plate for culture to obtain the entomopathogenic fungi with high pathogenicity to Egyptian icerya.

(3) Purification of entomopathogenic fungi

Culturing the isolate in PDA culture medium for 10 days, and eluting conidium with sterile water to obtain 1 × 10 extract³one/mL of spore suspension, the suspension was dropped on a slide glass with a cover glass, observed under a biological microscope, and a slide glass with only one conidium in one drop was inserted into the medium and cultured in an incubator to obtain 8 isolates in total of IJID001, IJID002, IJID003, IJID004, IJID005, IJID006, IJID007, and IJID 008.

Example 2 selection of Isaria javanicus strain IJID003

Entomopathogenic fungi are diverse in genetics, ecology, biology and the like, wherein different strains of the fungi exhibit significant differences in pathogenicity to target pests. The screening and obtaining of high-yield and high-quality strains are the first premise for obtaining better control effect. The excellent strain screening mainly considers 3 indexes, namely spore yield, colony growth rate and pathogenicity. The invention takes the 3 indexes as main bases to screen excellent highly pathogenic bacterial strains.

(1) Material preparation

A total of 8 isolates of purified IJID001, IJID002, IJID003, IJID004, IJID005, IJID006, IJID007 and IJID008 were cultured on PDA plates in an incubator at 27. + -. 1 ℃.

(2) Test insects and host plants

Egyptian Blackia amansii, a subcultured population from the institute for plant protection, Michelia alba, Guangzhou, institute for forestry and Garden science. A large number of cabbage seedlings (1.5m high) were purchased in the village and planted in the greenhouse of the institute for plant protection, the institute for forestry and garden science, Guangzhou City.

(3) Determination of colony growth rate and spore yield

Respectively eluting spores of 8 isolates of Isaria javanicus strain which are transferred to PDA plate medium and cultured for 10 days by using sterile water to prepare 1 × 10⁷10 mu L of conidium suspension with the concentration of one strain/mL is respectively dripped into the center of a PDA plate with the diameter of 9cm, the colony diameter is directionally measured every other day after hyphae grow out for 10 days, and each strain is repeated for 3 times. After the colony diameter was measured for the 5 th time, a sterilized punch was used to punch a hole from the center to the edge 1/2 of the colony, the hole was broken up with 0.02% tween-80, the mixture was stirred for 15min on a magnetic stirrer, filtered with gauze, counted with a hemocytometer, the data obtained was statistically analyzed by SPSS22.0 software, the mean and standard error were calculated, and the significance of the difference of the mean was multiple-compared by the LSD method. The regression equation is obtained by SPSS linear regression analysis, and the slope of the regression equation is the colony growth rate.

The results show that the colony growth rate and spore yield of 8 isolates are shown in Table 1, the growth rate of 8 isolates is basically the same, and the colony diameter after 20 days is expanded between 49mm and 55 mm. Wherein the IJID003 strain has largest spore yield of 0.85 × 10⁷one/mL, followed by 0.6X 10 of IJID006 strain⁷Strains IJID001, IJID004, IJID005, IJID007 and IJID008 were substantially the same and were each 0.125X 10⁷0.175X 10 per mL⁷0.15X 10 units/mL⁷0.125X 10 units/mL⁷particle/mL, 0.075X 10⁷one/mL.

TABLE 1 colony growth rate and sporulation yield (20d) of Isaria javanicus 8 isolates

Note: the same letters in the same number columns in the table indicate no significant difference at the 0.05 level.

(4) Pathogenicity of isolate to Lecanicillium pratensis nymph

Transferring 8 isolates to PDA plate, culturing for 10 days, adding 0.02% Tween-80 sterile water to wash spores after forming colony, stirring for 15min on magnetic stirrer, and adjusting spore concentration to 1 × 10 with blood counting chamber⁷Per mL spore suspension was prepared, sprayed evenly onto leaves of Brandy brandy with 40 Erythropha scales using a small hand sprayer, and allowed to air dry, in 0.02% Tween-80 sterile water, with 3 replicates per strain set. Inserting the treated leaf of herba Dracocephali into flower mud, placing into square culture dish with filter paper, and placing into illumination incubator at 27 + -1 deg.C (L: D ═ 14:10, RH)>90%) and the number of deaths from infection with icerya aegypti (significant hyphal coverage on the surface of the worm) was recorded daily, all mortality rates were corrected (corrected mortality rate-control mortality rate)/(1-control mortality rate) x 100%).

The results in table 2 show that the pathogenicity of the 4d strain of 8 strains to Egyptian blepharisma is obviously different, wherein IJID002, IJID003 and IJID006 are the most pathogenic, the death rates of the low-age nymphs of Egyptian blepharisma are respectively 96.6%, 95.4% and 97.75%, the mortality rates of the low-age nymphs of IJID001, IJID004, IJID005, IJID007 and IJID008 are respectively 79.2%, 81.8%, 87.3%, 87.5% and 88%.

TABLE 2 pathogenicity of Isaria javanicus Strain 8 isolates on the 2 st nymph of Erythium gracilis

Isolate strain	Mortality M. + -. SE (%)
		IJID001	79.2±0.8c
IJID002	96.6±0.4a
		IJID003	95.4±0.8a
IJID004	81.8±1.1c
		IJID005	87.3±2.7bc
IJID006	97.75±0.55a
		IJID007	87.5±2.5bc
IJID008
		88±2b
CK			10.25±2.75d

Note: the same letters in the same number columns in the table indicate no significant difference at the 0.05 level.

(5) Screening results of Excellent Strain of Isaria javanicus Strain

When screening excellent strains, the sporulation quantity, the pathogenicity and the colony growth rate of the strains are taken as important reference indexes. In the present invention, the three indexes are used as judgment criteria, and comparison analysis shows that, regarding sporulation quantity and pathogenicity, the isolates IJID003 and IJID006 are excellent, and have the characteristics of high pathogenicity and high sporulation quantity (Table 1 and Table 2), while the difference of colony growth rate of 8 strains is not significant. By comprehensively comparing various factors, IJID003 is the best strain.

EXAMPLE 3 identification of Strain IJID003

(1) Morphological characteristics of Strain IJID003

The strain IJID003 was inoculated into the center of a PDA medium plate, incubated at a constant temperature of 27. + -. 1 ℃ and the growth of colonies was observed every day and the color and morphology of colonies were recorded. Inoculating strain IJID003 to the center of another PDA culture medium plate, inserting sterilized cover glass (1cm × 1cm) into the culture medium about 1cm away from the inoculation point, culturing at 27 + -1 deg.C for about 5d until the hyphae stretch to the cover glass, taking out the cover glass, and observing hypha and spore morphology under optical microscope.

Morphological characteristics of strain IJID003 (FIGS. 1 and 2): on the PDA plate, the colony is circular, the diameter is 49 mm-55 mm, concentric rings are arranged, and gullies are formed on the culture medium, and the texture is thick downy. The colony had a pale yellow back. The color of the spore layer is light purple gray. The hyphae were transparent and colorless under microscope. The molecular spore stalk is coated with a rotasomal body formed by 2-4 bottle stalks, and the base parts of the bottle stalks are expanded in an oval shape and tapered upwards. Conidia grow on the phialides and form spore chains. The conidia are transparent, smooth and oblong. Conidium size is 4.5 μm (3.1 μm-6.5 μm). times.1.8 (1.5-2 μm).

(2) Sequence analysis of Strain IJID003

Inoculating strain IJID003 to the center of a PDA culture medium plate, culturing at a constant temperature of 27 +/-1 ℃, scraping hyphae growing on the PDA plate into an aseptic mortar by using an aseptic spoon after bacterial colonies grow over the whole culture dish, adding liquid nitrogen, grinding into powder, extracting genomic DNA of the strain IJID003 by using an SDS method, performing PCR amplification by using purified DNA as a template and adopting fungus universal primers ITS4 and ITS5, and recovering, purifying, connecting and transforming PCR products and performing DNA sequencing. By comparing homology with the ITS1-5.8S-ITS2 sequences of all eukaryotic organisms determined in GenBank, a phylogenetic tree of strain IJID003 was constructed (FIG. 3), and as a result, it was revealed that strain IJID003 and Isaria javanicus (Isaria javanica) were clustered together and their morphological characteristics were in accordance with those of Isaria javanicus (Isaria javanica), so that it was possible to identify strain IJID003 as Isaria javanicus.

In conclusion, the strain IJID003 is identified as Isaria javanicus (Isaria japonica) and is deposited in the China center for type culture Collection in 2018, 10 and 15 days, with the preservation number of CCTCC NO: m2018680.

Example 4 pathogenicity determination of Isaria javanicus IJID003 for Low-and advanced-age nymphs of Erysia pelyzoensis

By measuring the pathogenicity of the entomopathogenic fungi to the target pests, an important reference basis is provided for comprehensively evaluating the biological control potential of the entomopathogenic fungi. In the research, the Isaria javanicus IJID003 strain is used for carrying out pathogenicity measurement on 2-instar nymphs, 3-instar nymphs and female adults of Erysiphe aegypti to screen out the optimal age and concentration of the strain lethal to the three insect states of the Erysiphe aegypti.

(1) Test insects and host plants

The Egyptian Blackermark, a stable indoor Egyptian Blackermark source propagated in a greenhouse by plant protection institute of forestry and garden science. The white orchid is planted in a plant protection institute greenhouse of Guangzhou city forestry and garden science research institute, and potted seedlings are 100-120 cm high and used for expanding and propagating target insects.

(2) Treatment of test strains

Transferring Isaria javanicus IJID003 strain to PDA plate, culturing for 10 days, adding 0.02% Tween-80 sterile water to wash spore after forming colony, stirring for 15min on magnetic stirrer, filtering with two layers of medical gauze after spore is completely stirred uniformly, adjusting spore concentration to 1 × 108/mL with blood counting plate to obtain spore suspension, and diluting to 1 × 10⁷、1×10⁶、1×10⁵、1×10⁴10mL of 4 test concentrations are used.

(3) Virulence determination of IJID003 Strain on 2-instar nymphs, 3-instar nymphs and female adults of Lecanicillium lecanii

The spore suspensions with the 5 concentrations are respectively and uniformly sprayed on the cabbage leaves with 40 heads of nymphs of 2 years, nymphs of 3 years and female adults by a small-sized manual sprayer, the nymphs of 3 years and the female adults are taken out and naturally dried, and each strain is set in sterile water of 0.02 percent Tween-80 for 3 times. The treated white orchid leaves were inserted into floral foam, placed in square petri dishes with filter paper, then placed in a light incubator at 27 ± 1 ℃ (L: D ═ 14:10, RH > 90%) for cultivation, and the number of infection deaths of erichia gracilis (with obvious hypha coverage on the surface of the worm) was recorded every day (fig. 4), and continuously observed for 5 days.

The results in Table 3 show that the cumulative corrected mortality for 2-instar nymphs, 3-instar nymphs and female adults on day 5 after treatment with different concentrations of Isaria javanicus IJID003 strain. On the 2 nd day after inoculation, nymphs of all ages in each treatment begin to die, which shows that the Isaria javanicus IJID003 strain has strong lethal effect on Erythium amabilis. In the range of 1X 10 of the concentration measured⁴1X 10 to one/mL⁸Within one/mL, the pathogenicity of the medicine is obviously enhanced along with the increase of the concentration. At the highest concentration of 1X 10⁸The number per mL, the cumulative corrected mortality rates of 2-instar nymphs, 3-instar nymphs and female adults at 5d were 100%, 98.5% and 100%, respectively. At a concentration of 1X 10⁷The total corrected mortality rates of 2-year nymphs, 3-year nymphs and female adults are 96.25 percent, 82 percent and 50 percent respectively. At a concentration of 1X 10⁶The total corrected mortality rates of 2-year nymphs, 3-year nymphs and female adults are 83.75%, 61.5% and 8% respectively. At a concentration of 1X 10⁵The total corrected mortality rates of 2-year nymphs, 3-year nymphs and female adults are 48.75%, 13.5% and 4% respectively per mL. At a concentration of 1X 10⁴The total corrected mortality rates of 2-year nymphs, 3-year nymphs and female adults are 46.25%, 5.5% and 3% respectively per mL. At a spore concentration of 1X 10⁸At one/mL, the IJID003 strain has strong pathogenicity on 2-year nymphs, 3-year nymphs and female adults, and at 5d, the cumulative corrected mortality of the 2-year nymphs, 3-year nymphs and female adults is close to 100%. When the spore concentration is 1 × 10⁷At one/mL, differences began to appear in the cumulative corrected mortality rates for 2 st nymphs, 3 rd nymphs and female adults of the erichia pelykii.

Combination watch3, the spore concentration is 1X 10⁸LT of nymphs and female adults at 2 th and 3 th age at spore/mL₅₀1.89, 2.29 and 2.31 respectively. LT of nymphs and females at 2 to 3 years old at a spore concentration of 1X 107 spores/mL₅₀Respectively 2.24, 2.77 and 4.69. The comprehensive experiment results show that the virulence of the IJID003 strain is compared with that of different instars of Egyptia verruckeri: 2-year-old nymphs>3-year-old nymphs>Female imago, therefore, the IJID003 strain has good infection effect on 2-year nymph, and the nymph of 2-3 years is the best period for preventing and treating.

TABLE 3 cumulative corrected mortality of IJID003 strains at different concentrations on 2-instar nymphs, 3-instar nymphs and 5d female adults

Note: the same letters in the same number columns in the table indicate no significant difference at the 0.05 level.

TABLE 4 LT of IJID003 strains treated with different ages of Erigerus pelgii₅₀And regression equation

Example 5 outdoor infection experiment of Isaria javanicus IJID003 on adult Egyptian icerya

1. Preparing 2 pots of white orchid potted plant which is healthy in growth, 120cm high and has been propagated naturally Egyptian Blackermannia in the greenhouse, selecting Egyptian Blackermannia female adults with uniform heads, ensuring that each two leaves have 15 heads of female adults, and 5 treatment groups (1 × 10)⁴spore/mL, 1X 10⁵spore/mL, 1X 10⁶spore/mL, 1X 10⁷spore/mL, 1X 10⁸spores/mL) and 1 control group (0.02% Tween-80 sterile water), leaves were sterilized with medical gauze containing 75% alcohol, and 2mL of different concentrations were dispensed with a small nebulizerSpraying spore suspension to the back of leaf to ensure the full contact between female Erysiphe aegypti and spore suspension, covering the treated leaves with fresh-keeping bag, maintaining RH (80 + -10)%, and repeating each treatment for 3 times. Symptoms of infestation were observed starting on day 2 of infestation with entomopathogenic fungi, counted and photographed. Counting the corrected mortality of Erythium amansii in each age period, carrying out multiple analysis on the data by using SPSS22.0 and adopting single-factor variance analysis and LSD method, and when the p value is<At 0.05, the results of the analysis were considered to be statistically significant. Meanwhile, the probit analysis of SPSS22.0 software is applied to calculate the LT50 value and analyze the pathogenicity of the IJID003 strain to female adults of Egyptian Blackermus amansi cultivated in a pot outdoors.

2. As can be seen from Table 5, 1X 10 is used⁶spore/mL, 1X 10⁷spore/mL, 1X 10⁸When the female adults are treated at the spore/mL concentration, the female adults LT50 are 2.98, 4.98 and 6.18 in sequence. When the spore concentration is 1 × 10⁴spore/mL and 1X 10⁵At spore/mL, the IJID003 strain had no infective effect on the female adults.

TABLE 5 LT of IJID003 Strain outdoor treatment of female adults of Erysipela pelykii₅₀And regression equation

The results showed that the IJID003 strain was present in a range of spore concentrations (10)⁶～10⁸spore/mL) has stronger pathogenicity to female imagoes of Erypnia gracilis, and the pathogenic rate and the concentration of spore suspension have a dose effect relationship; with the increase of the concentration of spores, the cumulative corrected mortality of female Egyptian Blackie increases, the pathogenic rate is accelerated, and the LT is shortened₅₀。

Example 6 measurement of pathogenicity of Isaria javanicus IJID003 to female imago of Lecanicillium

By small hand-operated sprayers2mL of 1X 10⁷The strain IJID003 spore suspension of spore/mL was uniformly sprayed on the leaf sheets of Chinese hibiscus with 30 female imagoes of Chinese hibiscus mealybugs, taken out and naturally dried, and each strain was set for 3 replicates in 0.02% Tween-80 sterile water as a control. Inserting the treated hibiscus leaves into flower mud, placing the flower mud in a square culture dish with filter paper, and then placing the flower mud in a light incubator at 27 +/-1 ℃ (L: D is 14:10, RH)>90%) and the number of the infected and dead droops of the cotton bollworm (obvious hypha covering on the surface of the worm body) were recorded every day (fig. 5), and the cultivation was continuously observed for 6 days.

The results in FIG. 6 show that the product has a molecular weight of 1X 10⁷After the treatment of spores/mL Isaria javanicus IJID003 strain, the cumulative corrected mortality of Lecanicillium solenopsis increased with the increase of the number of days of inoculation. The cumulative corrected mortality rate for Leptosphaeria solenopsis at day 2 of inoculation was 10.4%. The cumulative corrected mortality rate for Leptosphaeria solenopsis at day 3 of inoculation was 19.7%. The cumulative corrected mortality rate for Leptosphaeria solenopsis at day 4 of inoculation was 33.9%. The cumulative corrected mortality rate for Leptosphaeria solenopsis at day 5 of inoculation was 46.3%. The cumulative corrected mortality rate for the Leptosphaeria solenopsis Leporis at day 6 of inoculation was 59.3%. Therefore, Isaria javanicanicus IJID003 strain has higher pathogenicity to Lecanicillium rubrum.

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 (6)

1. The application of Isaria javanicanicus in preventing and controlling coccid insects is characterized in that Isaria javanicus IJID003 which is an entomogenous fungus and is preserved in the China center for type culture collection in 2018, 10 and 25 months, and the preservation number is CCTCC NO: m2018680.

2. The use of claim 1, wherein the scale insect is icerya purchasi or mealybug.

3. The use of claim 2, wherein the scale insect is Eleucoccus aeagnus and Lecanicillium.

4. A biocontrol agent for coccid insects, which comprises Isaria javanicus IJID003 as defined in claim 1.

5. The biocontrol agent according to claim 4, wherein the Isaria javanicus spore concentration range is 10⁶～10⁸spores/mL.

6. The use of the biocontrol agent of claim 4 or 5 for controlling insects of the scale insect family.

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