Method for compounding and screening beauveria bassiana and attractant

Abstract

The invention relates to the technical field of biological control, in particular to a Beauveria bassiana and attractant compounding and screening method, which comprises the following steps: collecting fruit flies with Beauveria bassiana colonies and obtaining a plurality of Beauveria bassiana strains; obtaining a biological prevention and control evaluation value of the strain through indoor biological testing, and judging whether the performance of the strain meets a preset standard or not according to the biological prevention and control evaluation value; the strains with the performance meeting the preset standard are compounded with a plurality of attractants, and a plurality of mixed agents are obtained; the spore germination rate of each mixed agent is obtained through detection, and the optimal attractant is determined; according to an attraction effect evaluation value obtained through the attraction test, whether attraction meets a preset standard or not is judged; the spore concentration is increased under the condition that the attraction does not meet the preset standard, or the reason that the attraction does not meet the preset standard is determined according to the survival bacterium carrying rate, and the attraction temperature or the attraction duration is adjusted. The biological control effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of biological control, and particularly to a method for screening the compound of Beauveria bassiana and attractant. Background Art

[0002] As an important entomopathogenic fungus, Beauveria bassiana has been widely used in the biological control of agricultural and forestry pests. It infects host insects through the body wall and secretes toxins to kill them, which is environmentally friendly and not prone to drug resistance. However, in practical applications, the control effect of Beauveria bassiana is often limited by factors such as pest avoidance behavior, low spore survival rate in the field, and unstable infection efficiency. As a means of behavior regulation, attractants can simulate the chemical communication signals of pests to attract target insects to actively contact the pathogen, thereby increasing the infection opportunity of the fungus.

[0003] Chinese Patent Publication No.: CN112889844B discloses a method for controlling Culex pipiens pallens using Beauveria bassiana, which includes the following steps: 1) cultivating Beauveria bassiana to obtain a Beauveria bassiana culture; 2) centrifuging the Beauveria bassiana culture and collecting the precipitate, mixing the Beauveria bassiana precipitate evenly with 2 g of brown sugar powder, 1 g of algal extract, and 0.5 g of yeast extract powder, and drying it under the condition of 30 - 40°C to obtain a Beauveria bassiana mixture; dissolving 100 g of polylactic acid in 500 mL of acetone to obtain a polylactic acid solution; mixing the Beauveria bassiana mixture, polylactic acid, and different contents of urea evenly to prepare a spraying film solution containing different contents of urea; 3) using expandable polystyrene beads to prepare micro-pellet cores; and spraying the film on the micro-pellet cores multiple times to obtain mosquito control particles; 4) spreading the mosquito control particles into the water body where mosquito control is required, thereby achieving mosquito control.

[0004] However, the following problems exist in the prior art: the lack of screening and adjustment of attractants in the prior art leads to poor biological control effect. Summary of the Invention

[0005] Therefore, the present invention provides a method for screening the compound of Beauveria bassiana and attractant to overcome the problem of poor biological control effect caused by the lack of screening and adjustment of attractants in the prior art.

[0006] To achieve the above object, the present invention provides a method for screening the compound of Beauveria bassiana and attractant, including: Step S1, collecting fruit flies with Beauveria bassiana colonies and obtaining a number of Beauveria bassiana strains; Step S2, obtaining the biological control evaluation value of the strain through indoor biological tests and determining whether the performance of the strain meets the preset standard according to the biological control evaluation value; Step S3: Mix the strains that meet the preset standards with several kinds of attractants to obtain several mixtures. Step S4: Determine the optimal attractant by detecting the spore germination rate, attraction rate, amount of bacteria carried, and infection rate of the mixtures. Step S5: Determine whether the attraction meets the preset standards according to the evaluation value of the attraction effect obtained through the attraction test. Step S6: Under the condition that the attraction does not meet the preset standards, increase the spore concentration, or determine the reason why the attraction does not meet the preset standards according to the survival bacteria-carrying rate and adjust the attraction temperature or attraction duration.

[0007] Furthermore, the biological control evaluation value is jointly determined by the colony size and the spore production quantity.

[0008] Furthermore, determine whether the performance of the strain meets the preset standards according to the biological control evaluation value. Among them, if the biological control evaluation value is less than the preset control threshold, it is determined that the performance of the strain does not meet the preset standards, and the strain is re-screened. If the biological control evaluation value is greater than or equal to the preset control threshold, it is determined that the performance of the strain meets the preset standards, and step S3 is executed.

[0009] Furthermore, the attractants include methyl eugenol, linalool, ethyl acetate, protein hydrolysate, and raspberry ketone.

[0010] Furthermore, the evaluation value of the attraction effect is jointly determined by the attraction rate and the mortality rate of the fruit flies.

[0011] Furthermore, the attraction test process includes: Select two wire cages and put a preset number of female and male fruit flies into them respectively. Place white filter papers coated with the mixture and Beauveria bassiana reagent in the two wire cages respectively as the treatment group and the control group. After the first preset time period, count the number of fruit flies on each treatment filter paper to obtain the attraction rate of the fruit flies. After the second preset time period, obtain the mortality rate of the fruit flies.

[0012] Furthermore, determine whether the attraction meets the preset standards according to the evaluation value of the attraction effect. Among them, if the evaluation value of the attraction effect is less than the first preset evaluation threshold, it is determined that the attraction does not meet the preset standards, and the spore concentration is increased according to the difference between the first preset evaluation threshold and the evaluation value of the attraction effect. If the evaluation value of the attraction effect is greater than or equal to the first preset evaluation threshold and less than the second preset evaluation threshold, it is determined that the attraction does not meet the preset standards, and the reason why the attraction does not meet the preset standards is determined according to the ratio of the amount of bacteria carried in the surviving fruit flies to the amount of bacteria carried in the dead fruit flies. If the induced effect evaluation value is greater than or equal to the second preset evaluation threshold, it is determined that the induction meets the preset standard.

[0013] Further, the spore concentration is positively correlated with the difference value of the induced effect evaluation, where the difference value of the induced effect evaluation is the difference between the first preset evaluation threshold and the induced effect evaluation value.

[0014] Further, the reason for the induction not meeting the preset standard is determined according to the survival bacteria-carrying rate. If the survival bacteria-carrying rate is less than the preset bacteria-carrying rate, it is determined that the reason for the induction not meeting the preset standard is that the induction temperature does not meet the standard, and the induction temperature is increased according to the difference between the preset bacteria-carrying rate and the survival bacteria-carrying rate. If the survival bacteria-carrying rate is greater than or equal to the preset bacteria-carrying rate, it is determined that the reason for the induction not meeting the preset standard is that the bacteria-carrying amount of the fruit fly does not reach the peak value, and the induction test duration is increased according to the difference between the survival bacteria-carrying rate and the preset bacteria-carrying rate. The survival bacteria-carrying rate is the ratio of the bacteria-carrying amount in the surviving fruit flies to the bacteria-carrying amount in the dead fruit flies.

[0015] Further, there are several adjustment methods for the induction test duration, and the adjustment range of each adjustment method for the induction test duration is different.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention determines whether the performance of the strain meets the preset standard by obtaining the biological control evaluation value of the strain, determines the best attractant by detecting the spore germination rate of the mixture obtained by compounding the strain and the attractant, and further determines whether the induction meets the preset standard according to the induced effect evaluation value. Screening is carried out step by step from the strain performance, spore germination rate to the induced effect to ensure the best matching of the strain and the attractant, so as to ensure the control efficiency of the mixture.

[0017] Further, the present invention jointly determines the biological control evaluation value through the colony size and the spore production quantity, which more comprehensively reflects the potential of the strain. The performance of the strain is evaluated through the biological control evaluation value, making the screening process more scientific and accurate, avoiding the blindness of screening only by experience or a single index, and improving the accuracy and efficiency of screening.

[0018] Further, the present invention compounds the strains with qualified performance with a variety of attractants, and detects the spore germination rate, attraction rate, bacteria-carrying amount and infection rate of each mixture to determine the best attractant, taking into account the biological control performance of the strain and also fully considering the effects of the attractant on the strain and the pests, so as to achieve the optimal combination of the two.

[0019] Furthermore, the present invention jointly determines the evaluation value of the attraction effect through the attraction rate and mortality rate under a preset duration, making the evaluation of the attraction effect more comprehensive and scientific. At the same time, a comparative experimental design of a treatment group and a control group is adopted to further improve the accuracy and reliability of the evaluation.

[0020] Furthermore, when the attraction does not meet the preset standard, the present invention provides clear reasons and solutions. The reason for the attraction not meeting the standard is determined by the survival bacteria-carrying rate, and the attraction temperature or duration parameters are adjusted accordingly, achieving the rapid solution and optimization of the problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flowchart of the method for compound screening of Beauveria bassiana and attractant in an embodiment of the present invention; Figure 2 is a flowchart of determining whether the performance of a strain meets a preset standard according to the biological control evaluation value in an embodiment of the present invention; Figure 3 is a comparative broken line graph of the spore germination rate of Beauveria bassiana under different concentrations of attractant treatment in an embodiment of the present invention; Figure 4 is a comparative broken line graph of the effects of attractant protein hydrolysate and linalool on the spore concentration of Beauveria bassiana in an embodiment of the present invention; Figure 5 is a comparative broken line graph of the effects of attractant protein hydrolysate and linalool on the attraction rate of fruit flies in an embodiment of the present invention; Figure 6 is a comparative broken line graph of the effects of attractant protein hydrolysate and linalool on the bacteria-carrying amount of fruit flies in an embodiment of the present invention; Figure 7 is a comparative broken line graph of the effects of attractant protein hydrolysate and linalool on the infection rate of fruit flies in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0024] It should be noted that the data in this embodiment are all obtained through comprehensive analysis and evaluation of the historical detection data and corresponding historical detection results of the present invention in the three months before this detection. Those skilled in the art can understand that the determination method of the above single parameter of the present invention can be to select the value with the highest proportion according to the data distribution as the preset standard parameter, use weighted summation to take the obtained value as the preset standard parameter, substitute each historical data into a specific formula and take the value obtained by using this formula as the preset standard parameter or other selection methods, as long as it satisfies that the present invention can clearly define different specific situations in the single-item determination process through the obtained values.

[0025] Please refer to Figures 1 to 7 as shown, which are respectively the flowchart of the method for compound screening of Beauveria bassiana and attractants in the embodiment of the present invention; the flowchart of determining whether the performance of the strain meets the preset standard according to the biological control evaluation value in the embodiment of the present invention; the comparative broken line graph of the spore germination rate of Beauveria bassiana under different concentrations of attractants in the embodiment of the present invention; the comparative broken line graph of the influence of attractant protein hydrolysate and linalool on the spore concentration of Beauveria bassiana in the embodiment of the present invention; the comparative broken line graph of the influence of attractant protein hydrolysate and linalool on the attractant rate of fruit flies in the embodiment of the present invention; the comparative broken line graph of the influence of attractant protein hydrolysate and linalool on the bacteria-carrying amount of fruit flies in the embodiment of the present invention; the comparative broken line graph of the influence of attractant protein hydrolysate and linalool on the infection rate of fruit flies in the embodiment of the present invention.

[0026] The method for compound screening of Beauveria bassiana and attractants in the embodiment of the present invention includes: Step S1, collecting fruit flies with Beauveria bassiana colonies and obtaining a number of Beauveria bassiana strains; Step S2, obtaining the biological control evaluation value of the strain through indoor biological tests and determining whether the performance of the strain meets the preset standard according to the biological control evaluation value; Step S3, compounding the strains whose performance meets the preset standard with several kinds of attractants to obtain several mixtures; Step S4, determining the best attractant by detecting the spore germination rate, attractant rate, bacteria-carrying amount and infection rate of the mixture; Step S5, determining whether the attraction meets the preset standard according to the attractant effect evaluation value obtained through the attraction test; Step S6, increasing the spore concentration under the condition that the attraction does not meet the preset standard, or determining the reason why the attraction does not meet the preset standard according to the survival bacteria-carrying rate and adjusting the attraction temperature or attraction duration.

[0027] Specifically, the process of step S1 includes: Step S101, selecting a location with a large area damaged by fruit flies and hanging sticky yellow boards for half a month; Step S102: Recycle the yellow boards, and identify the fruit flies with white hyphae covering the surface of the insect bodies through microscope observation as suspected infected insect bodies; Step S103: Place the suspected infected insect bodies in a petri dish with moist filter paper (RH>90%), and culture them at 25°C for 5 days; Step S104: Extract DNA from the moisturized cultured hyphae and compare it with the Beauveria bassiana sequence; Step S105: Identify the infected fruit flies with successful strain comparison, pick several spores from the surface of the insect bodies, and inoculate them into several PDA culture media respectively, and culture them at 25°C for 7 days to obtain several purified strains.

[0028] Specifically, the biological control evaluation value is jointly determined by the colony size and the spore production quantity, and is calculated by the following formula: , in the formula, is the biological control evaluation value, is the first weight coefficient, set , D is the colony diameter, is the colony diameter threshold, set , is the second weight coefficient, set , is the spore production quantity, is the spore production quantity threshold, set is 2×10 8 spores / cm².

[0029] Specifically, judge whether the performance of the strain meets the preset standard according to the biological control evaluation value. Among them, if the biological control evaluation value is less than the preset control threshold of 0.8, it is determined that the performance of the strain does not meet the preset standard, and the strain is re-screened; If the biological control evaluation value is greater than or equal to the preset control threshold, it is determined that the performance of the strain meets the preset standard, and step S3 is executed.

[0030] In the embodiment of the present invention, the value of the preset control threshold is 0.8, but the above value is not limited thereto, and those skilled in the art can adjust this value according to actual needs.

[0031] Specifically, the attractant includes methyl eugenol, linalool, ethyl acetate, protein hydrolysate, and raspberry ketone.

[0032] Example 1

[0033] Germination rate determination: Methyl eugenol, linalool, ethyl acetate, protein hydrolysate, and raspberry ketone were respectively mixed with 0.5% dimethyl sulfoxide (DMSO) to prepare solutions with concentrations of 0.1%, 1%, and 10% v / v. High-quality Beauveria bassiana grown on PDA medium for 7 days was selected and prepared into a spore suspension of 1×10 6 spores / mL with 0.1% Tween-80 solution. 50 μL of different concentrations of attractant solutions were respectively dropped on glass slides, and then 10 μL of the spore suspension was added. The spore germination rate was calculated after 6 hours. The control group used 0.5% DMSO solution. The experimental results are as Figure 3 shown.

[0034] It can be seen from Figure 3 that when the concentration of the attractant is less than or equal to 1% v / v, the protein hydrolysate and linalool have little effect on the spore germination rate of Beauveria bassiana, indicating that these two attractants have good biocompatibility with Beauveria bassiana within the concentration range of 0.1% - 1%. Therefore, the attractants protein hydrolysate and linalool were selected for the next experiment.

[0035] Example 2

[0036] Spore concentration determination: 15 g of wheat, 5 g of oat flour, 3 g of peptone, 2 g of glucose, 500 μL of potassium dihydrogen phosphate, and 500 μL of magnesium sulfate were weighed according to a predetermined ratio. After 3 hours of high-temperature sterilization, they were respectively mixed with linalool and protein hydrolysate, and the attractant concentrations were 0.001 ml / g, 0.01 ml / g, and 0.1 ml / g. Then 1 mL of a Beauveria bassiana suspension with a concentration of 1×10 8 spores / mL was added. 15 kinds of culture media were prepared for three concentration gradients of each attractant, and each was repeated 5 times. The culture media were poured into glass petri dishes with a diameter of 15 cm and cultured for 5 days at 28°C and a relative humidity of 80%. After the culture was completed, they were dried at 60°C for 48 hours. 0.1 g of the culture medium was taken, 100 mL of 0.1% Tween-80 solution was added, and after grinding and filtering, the spore concentration was measured by the hemocytometer method. The control group culture medium did not add attractant. The experimental results are as Figure 4 shown.

[0037] It can be seen from Figure 4 that when the concentration is less than or equal to 0.01 mL / g, the protein hydrolysate and linalool have little effect on the spore concentration of Beauveria bassiana.

[0038] Example 3

[0039] Determination of the attraction rate: The culture media with different attractants and concentrations cultured for 3 days were placed into a wind tunnel device (with dimensions of 2 m in length, 1 m in width, 1 m in height, and a wind speed of 1 m / s). The culture medium with the attractant was placed on one side of the wind tunnel, and the control culture medium was placed on the other side. White cardboard coated with sticky fly glue was fixed at the outer edge of the culture medium. 40 fruit flies were released, and the number of fruit flies on each cardboard was recorded after 6 hours. In the control group, the culture media without attractant were placed on both sides of the wind tunnel. Each treatment was repeated 5 times. The experimental results are as Figure 5 shown.

[0040] As can be seen from Figure 5 , linalool has a strong attraction effect on fruit flies at a concentration of 0.01 mL / g.

[0041] Example 4

[0042] Determination of the bacteria-carrying amount: The culture medium was placed into the wind tunnel experimental device, and 40 fruit flies were introduced. After 6 hours, the fruit flies were taken out, frozen for 2 minutes, and then placed into 50 mL of 0.1% Tween-80 solution. After gently shaking for 5 minutes, the fruit flies were taken out, and the spore concentration in the soaking solution was measured. Each treatment was repeated 5 times.

[0043] As can be seen from Figure 6 , linalool treatment can significantly increase the bacteria-carrying amount of fruit flies at a concentration of 0.01 mL / g.

[0044] Example 5

[0045] Determination of the infection rate: The culture medium was placed into the wind tunnel experimental device, and 40 fruit flies were introduced. After 6 hours, the fruit flies were taken out and placed into a wire cage with breeding conditions of 28 °C, relative humidity of 80%, and a photoperiod of 16:8. The dead fruit flies were recorded every day and cultured on PDA culture medium. The fruit flies that died of infection were judged by the appearance of white hyphae on PDA.

[0046] As can be seen from Figure 7 , linalool at 0.01 mL / g and protein hydrolysate at 0.1 mL / g can significantly increase the infection rate of fruit flies.

[0047] In summary, according to the experimental results of Examples 1-5, it can be seen that linalool at 0.01 mL / g has good effects in terms of the attraction rate, bacteria-carrying amount, and infection rate. Therefore, the optimal attractant is determined to be linalool, and the optimal concentration is 0.01 mL / g.

[0048] Specifically, the infection rate = the number of fruit flies with white hyphae / the total number of fruit flies × 100%.

[0049] Specifically, the evaluation value of the attracting effect is jointly determined by the attracting rate and the mortality rate of the fruit flies. The evaluation value of the attracting effect = attracting weight coefficient × attracting rate + death weight coefficient × mortality rate, where the attracting rate = (the number of dead flies in the treatment group - the number of dead flies in the control group) / the total number of flies in a single cage × 100%, the mortality rate = the number of dead flies in the treatment group / the total number of flies in a single cage. The attracting weight coefficient is set to 0.6, and the death weight coefficient is set to 0.4.

[0050] Specifically, the dead fruit flies are judged by the appearance of white mycelia on the surface of the insect body.

[0051] Specifically, the attracting test process includes: Select two net cages and put 50 female and male fruit flies with a preset quantity into each respectively; Place white filter papers coated with the mixture and Beauveria bassiana reagent in the two net cages respectively as the treatment group and the control group; After the first preset time period of 24 hours, count the number of fruit flies on each treatment filter paper to obtain the attracting rate of the fruit flies, and immediately take out the filter paper of the treatment group, transfer the fruit flies on the filter paper to a new cage without medicine. After another second preset time period of 72 hours, count the number of dead fruit flies on the filter paper to obtain the mortality rate of the fruit flies.

[0052] Specifically, it is judged whether the attraction meets the preset standard according to the evaluation value of the attracting effect. Among them, if the evaluation value of the attracting effect is less than the first preset evaluation threshold of 0.75, it is judged that the attraction does not meet the preset standard, and the spore concentration is increased according to the difference between the first preset evaluation threshold and the evaluation value of the attracting effect; If the evaluation value of the attracting effect is greater than or equal to the first preset evaluation threshold and less than the second preset evaluation threshold of 0.83, it is judged that the attraction does not meet the preset standard, and the reason for the attraction not meeting the preset standard is determined according to the ratio of the amount of bacteria carried by the surviving fruit flies to the amount of bacteria carried by the dead fruit flies; If the evaluation value of the attracting effect is greater than or equal to the second preset evaluation threshold, it is judged that the attraction meets the preset standard.

[0053] In the embodiment of the present invention, the value of the first preset evaluation threshold is 0.75, and the value of the second preset evaluation threshold is 0.83. However, the above values are not limited to this, and those skilled in the art can adjust the above values according to actual needs.

[0054] Specifically, the spore concentration is positively correlated with the difference in the attracting effect evaluation. Among them, if the difference in the attracting effect evaluation is less than the first preset effect evaluation difference of 0.12, the spore concentration is increased to the corresponding value by using the first concentration adjustment coefficient of 1.5; If the difference in the evaluation of the attraction effect is greater than or equal to the first preset evaluation difference of the attraction effect and less than the second preset evaluation difference of the attraction effect, which is 0.18, then use the second concentration adjustment coefficient 2 to increase the spore concentration to the corresponding value; If the difference in the evaluation of the attraction effect is greater than or equal to the second preset evaluation difference of the attraction effect, then use the third concentration adjustment coefficient 3 to increase the spore concentration to the corresponding value; The difference in the evaluation of the attraction effect is the difference between the first preset evaluation threshold and the evaluation value of the attraction effect.

[0055] In the embodiment of the present invention, the initial spore concentration is 1*10 8 spores / mL, the first preset evaluation difference of the attraction effect takes the value of 0.12, and the second preset evaluation difference of the attraction effect takes the value of 0.18. However, the above values are not limited to this, and those skilled in the art can adjust the above values according to actual needs.

[0056] Specifically, determine the reason why the attraction does not meet the preset standard according to the survival rate of bacteria-carrying flies. Among them, if the survival rate of bacteria-carrying flies is less than the preset bacteria-carrying rate of 60%, it is determined that the reason why the attraction does not meet the preset standard is that the attraction temperature does not meet the standard, and the attraction temperature is increased according to the difference between the preset bacteria-carrying rate and the survival rate of bacteria-carrying flies; If the survival rate of bacteria-carrying flies is greater than or equal to the preset bacteria-carrying rate, it is determined that the reason why the attraction does not meet the preset standard is that the bacteria-carrying amount of fruit flies does not reach the peak, and the attraction test duration is increased according to the difference between the survival rate of bacteria-carrying flies and the preset bacteria-carrying rate; The survival rate of bacteria-carrying flies is the ratio of the bacteria-carrying amount in the surviving fruit flies to the bacteria-carrying amount in the dead fruit flies.

[0057] In the embodiment of the present invention, the preset bacteria-carrying rate takes the value of 60%. However, the above value is not limited to this, and those skilled in the art can adjust this value according to actual needs.

[0058] Specifically, there are several adjustment methods for the attraction test duration, and each adjustment method has a different adjustment range for the attraction test duration. Among them, if the difference in the bacteria-carrying rate is less than the first preset difference in the bacteria-carrying rate of 5%, then use the first duration adjustment coefficient 1.2 to increase the attraction test duration to the corresponding value; If the difference in the bacteria-carrying rate is greater than or equal to the first preset difference in the bacteria-carrying rate and less than the second preset difference in the bacteria-carrying rate of 12%, then use the second duration adjustment coefficient 1.5 to increase the attraction test duration to the corresponding value; If the difference in the bacteria-carrying rate is greater than or equal to the second preset difference in the bacteria-carrying rate, then use the third duration adjustment coefficient 2.0 to increase the attraction test duration to the corresponding value; The difference in the bacteria-carrying rate is the difference between the survival rate of bacteria-carrying flies and the preset bacteria-carrying rate.

[0059] In the embodiment of the present invention, the initial induction test duration is 24 h, the value of the first preset difference in bacteria-carrying rate is 5%, and the value of the second preset difference in bacteria-carrying rate is 12%. However, the above values are not limited to this, and those skilled in the art can adjust the above values according to actual needs.

[0060] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0061] The above are only the preferred embodiments of the present invention and are not used to limit the present invention; for those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for screening the compound of Beauveria bassiana and attractant, characterized in that, Including: Step S1: Collect fruit flies with Beauveria bassiana colonies and obtain a number of Beauveria bassiana strains; Step S2: Obtain the biological control evaluation value of the strains through indoor biological tests and determine whether the performance of the strains meets the preset standards according to the biological control evaluation value; Step S3: Compound the strains whose performance meets the preset standards with several kinds of attractants to obtain several mixtures; Step S4: Determine the optimal attractant by detecting the spore germination rate, attraction rate, spore load and infection rate of the mixtures; Step S5: Determine whether the attraction meets the preset standards according to the attraction effect evaluation value obtained through the attraction test; Step S6: Increase the spore concentration under the condition that the attraction does not meet the preset standards, or determine the reason why the attraction does not meet the preset standards according to the survival spore load rate and adjust the attraction temperature or attraction duration.

2. The method for screening the compound of Beauveria bassiana and attractant according to claim 1, characterized in that, The biological control evaluation value is jointly determined by the colony size and the sporulation quantity.

3. The method for screening the compound of Beauveria bassiana and attractant according to claim 2, characterized in that, Determine whether the performance of the strain meets the preset standards according to the biological control evaluation value. Among them, if the biological control evaluation value is less than the preset control threshold, it is determined that the performance of the strain does not meet the preset standards, and the strain is re-screened; If the biological control evaluation value is greater than or equal to the preset control threshold, it is determined that the performance of the strain meets the preset standards, and step S3 is executed.

4. The method for screening the compound of Beauveria bassiana and attractant according to claim 3, characterized in that, The attraction effect evaluation value is jointly determined by the attraction rate and the mortality rate of fruit flies.

5. The method for screening the compound of Beauveria bassiana and attractant according to claim 4, wherein The attraction test process includes: Select two wire cages and put a preset number of female and male fruit flies into them respectively; Place white filter papers coated with the mixture and Beauveria bassiana reagent in the two wire cages respectively as the treatment group and the control group; After the first preset time period, count the number of fruit flies on each treatment filter paper to obtain the attraction rate of fruit flies. After the second preset time period, obtain the mortality rate of fruit flies.

6. The method for screening the compound of Beauveria bassiana and attractant according to claim 5, characterized in that, Determine whether the attraction meets the preset standards according to the attraction effect evaluation value. Among them, if the attraction effect evaluation value is less than the first preset evaluation threshold, it is determined that the attraction does not meet the preset standards, and the spore concentration is increased according to the difference between the first preset evaluation threshold and the attraction effect evaluation value; If the attraction effect evaluation value is greater than or equal to the first preset evaluation threshold and less than the second preset evaluation threshold, it is determined that the attraction does not meet the preset standards, and the reason why the attraction does not meet the preset standards is determined according to the ratio of the spore load in the surviving fruit flies to the spore load in the dead fruit flies; If the attraction effect evaluation value is greater than or equal to the second preset evaluation threshold, it is determined that the attraction meets the preset standards.

7. The method for screening the compound of Beauveria bassiana and attractant according to claim 6, characterized in that, The spore concentration is positively correlated with the attraction effect evaluation difference, where the attraction effect evaluation difference is the difference between the first preset evaluation threshold and the attraction effect evaluation value.

8. The method for screening the compound of Beauveria bassiana and attractant according to claim 7, characterized in that Determine the reason why the attraction does not meet the preset standards according to the survival spore load rate. Among them, if the survival spore load rate is less than the preset spore load rate, it is determined that the reason why the attraction does not meet the preset standards is that the attraction temperature does not meet the standard, and the attraction temperature is increased according to the difference between the preset spore load rate and the survival spore load rate; If the survival bacteria-carrying rate is greater than or equal to the preset bacteria-carrying rate, it is determined that the reason for the lure not meeting the preset standard is that the bacteria-carrying amount of the fruit fly has not reached the peak, and the lure test duration is increased according to the difference between the survival bacteria-carrying rate and the preset bacteria-carrying rate; The survival bacteria-carrying rate is the ratio of the bacteria-carrying amount in the surviving fruit flies to the bacteria-carrying amount in the dead fruit flies.

9. The method for screening the compound of Beauveria bassiana and attractant according to claim 8, characterized in that, There are several adjustment methods for the lure test duration, and each adjustment method has a different adjustment range for the lure test duration.

10. The method for screening the compound of Beauveria bassiana and attractant according to claim 9, characterized in that, The attractant includes methyl eugenol, linalool, ethyl acetate, protein hydrolysate, and raspberry ketone.

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