CN111436424A

CN111436424A - Particle carrier, biopesticide particle and preparation method thereof

Info

Publication number: CN111436424A
Application number: CN202010276421.2A
Authority: CN
Inventors: 束长龙; 耿丽丽; 刘琪; 张�杰; 宋福平; 彭琦
Original assignee: Institute of Plant Protection of Chinese Academy of Agricultural Sciences
Current assignee: Institute of Plant Protection of Chinese Academy of Agricultural Sciences
Priority date: 2020-04-09
Filing date: 2020-04-09
Publication date: 2020-07-24

Abstract

The invention relates to a particle carrier, a biological pesticide particle and a preparation method thereof, and belongs to the technical field of biological pesticides. A particle carrier of a biological insecticide is prepared by mixing corn flour, peanut meal and bentonite according to a proportion, adding a proper amount of water, and preparing into particles by a single-rod spiral puffing granulator, wherein the particle size is 2.0-4.8 mm. The particle carrier is a universal carrier of the biological insecticide, the biological insecticide can be adsorbed on the surface of the particle carrier by adopting a conventional impregnation method for chemically preparing the catalyst, and then the biological insecticide is directly broadcast in the field by adopting an agricultural broadcast sowing machine. Under the environment of warm and moist in the field, the biological insecticide can be amplified by dozens of times, so that the consumption cost of the biological insecticide is greatly saved, and the burden of an agricultural owner is reduced. The invention provides a particle carrier of a biological insecticide, provides a new thought for biological pesticides, and has important significance for promoting biological control and green control of underground pests such as grubs and the like.

Description

Particle carrier, biopesticide particle and preparation method thereof

Technical Field

The invention relates to the technical field of biological pesticides, in particular to a particle carrier of a biological pesticide, a biological pesticide particle and a preparation method thereof.

Background

Grubs are a general term for larvae of insects in the family of tortoises, which inhabit the ground and are the underground parts of harmful crops, and adults feed on the overground parts of plants and return to the soil to lay eggs. The grubs which are harmful crops in China mainly comprise 3 Holotrichia parallela, Holotrichia oblita and Aerugo beetle (Anomala pulena Motschusky), wherein the Holotrichia parallela generates 1 generation in 2 years, and the Holotrichia parallela and the Aerugo beetle generate 1 generation in 1 year; the larval stage of Holotrichia parallela is generally 330-450 d, the larval stage of Holotrichia parallela and Holotrichia diomphalia Bates is generally 300-330 d, and the larval stage of Holotrichia parallela and Holotrichia diomphalia Bates can be harmful in the whole growth period of crops such as peanuts, soybeans and the like; the service life of Holotrichia parallela adults is generally 100-150 d, the service life of Holotrichia parallela adults is generally 110-390 d, the service life of Holotrichia parallela adults is generally 50-70 d, the Holotrichia parallela adults do not concentrate on laying eggs, the laying places are not fixed, and the biological characteristics make the Holotrichia parallela extremely difficult to control. The biological insecticide has the advantages of environmental friendliness, biological safety to a target and the like, but has the problems of high prevention and control cost, poor environmental adaptability, short lasting period and the like in the grub prevention and control aspect, so that the application of the biological insecticide is limited.

Bt, beauveria bassiana, metarhizium anisopliae and the like are the most commonly used biopesticides. Bt acts on target pests through the digestive tract. Bt-producing Insecticidal Crystal Proteins (ICPs) are ingested and activated by proteases in the insect gut, the activated Insecticidal Proteins further bind to specific receptors on the surface of the midgut epithelial cells, form perforations, and cause apoptosis, Bt enters the blood lumen with intestinal bacteria, causing sepsis, and further killing target pests [ Shore Zones, leading to the development of molecular mechanisms of Bacillus thuringiensis Insecticidal Crystal Proteins [ J ]. bioengineering progress, 2001, (06):38-42 ]. Conidia of beauveria bassiana and metarhizium anisopliae directly act on target insects through body surfaces. Conidia are attached to and germinate on the body surface of the insect, formed bud tubes penetrate through the epidermis of the insect and enter a blood cavity, hyphae continuously grow in the blood cavity and release toxin, and finally target pests are killed [ Bozhijian, Chengning, Palijun, Beauveria bassiana disease treatment mechanism research on the insect [ J ]. Wuyi science, 2000,16: 105-. Because Bt and stiff fungus have different action mechanisms, the combined use of Bt and stiff fungus can improve the insecticidal effect [ Penguo, Zhang Shuling, Zhang Wei, and the like ] the research on the combined indoor insecticidal activity of insecticidal fungus and Bacillus thuringiensis to spodoptera frugiperda [ J ]. Chinese biological prevention and control academy of sciences, 2019, (5): 735-.

The peanut meal is a product of peanut kernels after oil extraction [ usually made from Zizhai, Huanghailong, Shiwei, characteristics and fermentation advantages of a raw material of a fermented feed [ J ]. grain and feed industry, 2019, (01):44-48 ]. Researches show that the fermented peanut meal has a remarkable promoting effect on the growth of plants [ Liu Caiyun, Chenduo flower, Liu jin Yang, and the like. Research shows that the biological control microorganism can promote the growth of crops [ Ration, Baiyun, Caona, and the like ] through hydrolyzing small molecules generated by organic matters and compounds formed by metabolism by hydrolytic enzyme secreted by the biological control microorganism in the proliferation process [ J ] research on the growth promotion effect of beauveria bassiana on corns in different application modes [ J ] research in tropical crops, 2017,38(2): 206-. Therefore, in the future, in the process of controlling underground pests such as grubs and the like, the granular carrier using peanut meal as a main raw material and carrying biocontrol microorganisms has a value of further research on whether the growth and development of plants are positively influenced.

Grub is a general name of insect larvae in the general family of coleoptera scarab beetles (scarabaeaoedea), and it is counted that 86% of the damage of the underground part of crops is caused by grub hazards [ yaoqing, zhangong, butte, review and prospect of the scarab seed control research [ J ]. northeast university of forestry, 2003,31(3):64-66 ]. The grub has the characteristics of multiple species, food impurities, hidden activities, long pest damage time, wide distribution and the like, and is extremely difficult to monitor and control [ Weihongjun, Huangwenqin, Chinese underground pest research summary [ J ]. insect knowledge 1992,29(3):168- & 170. Zzhili, Chinese economic insect anzhi: Coleoptera Tortoise general family larva [ M ]. Beijing: scientific Press, 1984.] Anitha V, Rogers D J, Wightman J, et al.distribution and distribution of white grubs (Coleoptera: Scarabaeidae) on groundnutin southern Indinia [ J ]. Crop Protection,2006,25:732- & 740 ]. At present, the main means for controlling the grubs is to apply chemical pesticides to the roots of crops, and by 2 months of 2020, 350 chemical pesticides (http:// www.chinapesticide.org.cn/hysj/index. jhtml) are contained in 351 pesticide products for controlling the grubs registered in China, while 1 beauveria bassiana wettable powder is contained in biological pesticides (PD20102133, ecological member of Tian Jiangxi Ming Co., Ltd.). The biological insecticide has the defects of high production cost, poor lodging capability of spores in soil and the like, so that the problems of large prevention and treatment use amount and high cost are caused.

The biological insecticide has the advantages of safety, no toxicity, no residue, environmental friendliness [ Chengkun. underground pest grub Research progress [ J ] Guilin agriculture, 2018, (12) 66.Jouzani G, Valijiana E, Sharafil R. Thuringingiensis: a sucessful pesticide with insect pests such as Schopper species and insects [ J ] Applied Microbiology and Biotechnology,2017, 101: 2691. loop 1. in the course of biological application of the biological insecticide such as the biological insecticide of the microorganism, wherein the biological insecticide has better effect in the field of the Bacillus thuringiensis [ Ohberi M, Wahana H, Sano S, et al, the insect pest of the insect pest grub strain and the biological insecticide of the biological insecticide such as the insect pest of the insect pest grub virus, the insect pest of the blue beetle, the blue egg white sea insect pest, the insect pest, the insect pest, the insect pest, the pest.

The previous laboratory studies of the applicant show that Bt strains (Bt185) effective for grubs can grow on a culture medium prepared from peanut meal and other raw materials and produce insecticidal proteins [ Liulixia, monamine, Liuchunqin, and the like ] Bt soil granules for grubs control are screened [ J ]. Chinese biological control academy, 2017,33(1):70-78 ], but due to the characteristics of the materials, the puffed peanut meal cannot be regularly granular and can only be pressed into tablets with biological preparation powder, and the method is not suitable for sowing in agricultural machinery. The Chinese patent application of the applicant, namely 'a medicament and application thereof' (application number: 201610206934X), discloses a medicament which is prepared by crushing puffed peanut meal and then pressing the crushed peanut meal and microcrystalline fibers into tablets.

Disclosure of Invention

Aiming at the defects in the field, the particle carrier of the biological medicament is prepared according to the diameter specification (2.0-4.8 mm) of urea particles, can be combined with various biological medicaments, and can be broadcast in the field by using a machine for broadcasting fertilizer particle products such as urea and the like.

A particle carrier of a biological insecticide comprises the following components in percentage by mass: 15-40% of corn flour, 50-60% of peanut meal and 10-35% of bentonite; the particle carrier is prepared by the following method:

the corn flour, the peanut meal and the bentonite are weighed according to the mass ratio, mixed into raw material powder, added with water accounting for 15-20% of the mass of the raw material powder, uniformly mixed and prepared into particles through a single-rod spiral puffing granulator, wherein the particle size is 2.0-4.8 mm.

Preferably: 17-30% of corn flour, 50-60% of peanut meal, 20-33% of bentonite and 20% of water added as raw material powder.

More preferably: 17% of corn flour, 50% of peanut meal and 33% of bentonite.

The bentonite is calcium bentonite; the particle size of the bentonite is 80-400 meshes.

The preparation method of the granular carrier of the biological insecticide comprises the steps of weighing corn flour, peanut meal and bentonite according to the mass ratio, mixing the corn flour, the peanut meal and the bentonite into raw material powder, adding water accounting for 15-20% of the mass of the raw material powder, uniformly mixing, and preparing into granules by a single-rod spiral puffing granulator, wherein the puffing temperature is 120 ℃, and the pore diameter of a granulating mould is 3 mm.

A biopesticide granule comprises the granule carrier and a biopesticide adsorbed on the granule carrier.

The biological insecticide is Bt bacteria and/or beauveria bassiana.

The biological insecticide is Bt185 and/or Beauveria bassiana.

The application of the biological pesticide granules in preventing and controlling soil insects.

The underground pests are grubs.

The preparation method of the biological pesticide granules comprises the steps of suspending the biological pesticide in water, adding the granule carrier into the suspension, stirring or spraying the biological pesticide suspension onto the granule carrier, so that the biological pesticide is uniformly adsorbed on the surface of the granule carrier.

On the basis of the earlier-stage research in a laboratory, the applicant further researches Bt and beauveria bassiana particle carriers suitable for being applied to the existing agricultural machinery, and the single-screw puffing equipment is adopted to prepare particles with corresponding sizes according to the diameter specification (2.0-4.8 mm) of urea particles. According to the invention, corn flour and peanut meal are used as a composite nutrient medium, cheap and good bentonite is used as a carrier, the formula composition and content are optimized, high-temperature (120 ℃) reaction is carried out under screw extrusion to obtain expanded particles with the particle size of 2.0-4.8 mm, the expanded particles keep shapes in water and are not broken during stirring, and a better culture and proliferation space is provided for the biological insecticide, so that the proliferation multiple of the biological insecticide in soil can reach more than 40 times. Meanwhile, the biological pesticide particles can be mixed with fertilizers such as urea and the like for broadcasting.

The particle carrier is a universal biological insecticide carrier, and the biological insecticide can be adsorbed on the surface of the particle carrier by adopting a conventional impregnation method or a spraying and stirring method for chemically preparing a catalyst, and then is directly broadcast in the field by adopting an agricultural broadcast sowing machine. Under the environment of warm and moist in the field, corn flour and peanut meal are used as components of a biological insecticide culture medium, and bentonite is not only a forming agent, but also has larger specific surface area and water adsorption and retention capacity, so that larger adhesion propagation space and water are provided for microbial pesticides, the biological insecticide can be amplified by dozens of times, and can survive in soil for a longer time.

The granular carrier developed by the invention can proliferate various biocontrol microorganisms effective on grubs, and not only can utilize CO released by the effective biocontrol microorganisms of the grubs₂The grub is trapped and killed, and the amount of insecticidal microorganisms and insecticidal proteins in soil can be increased through proliferation, so that the grub killing chance is improved. In addition, the granule developed by the research has better structural strength under the water absorption condition, so that the internal nutrition can be slowly released, proper water is kept, the survival time of the insecticidal microorganism in the soil can be prolonged, and the grub control effect is further improved. Therefore, the particle carrier developed by the research can be used for reducing the prevention and treatment cost of the grub, improving and prolonging the prevention and treatment effect, and provides a new idea for the biological prevention and treatment of the grub. The peanut meal and the corn meal are organic fertilizer raw materials, and the growth of crops can be promoted by micromolecules generated by decomposing organic matters by hydrolase secreted by biocontrol microorganisms in the proliferation process and compounds formed by metabolism, so that the particle carrier disclosed by the invention can also promote the growth and development of plants.

The application evaluates Bt and beauveria bassiana strains effective on Holotrichia parallela, the Bt and the beauveria bassiana strains have no antagonistic effect and can be proliferated on a particle carrier, and further insecticidal activity determination shows that the Bt and the beauveria bassiana strains can be synergistically used to remarkably improve insecticidal effect. The related research results provide reference data for further research and development and use of the grub biocontrol product.

In summary, the application prepares the particle carrier which can be applied by modern farm machinery, has stable structure and can proliferate microorganisms for effectively preventing and controlling grubs by optimizing the process and the formula, so that the effect of the particle carrier on improving the insecticidal activity of Bt and beauveria bassiana is clarified, and related research results provide a new idea for developing high-efficiency biological insecticides for the grubs, and have important significance for promoting biological control and breaking through the bottleneck of biological control of the current grubs.

Drawings

FIG. 1 preparation of granular carriers with different ratios of nutrients and morphological change after water absorption

FIG. 2 measurement of particle carrier diameters for different ratios of nutrients

FIG. 3 weight measurement of particulate carriers with different ratios of nutrients

FIG. 4 fluorescent detection of proliferation of Bt185-gfp on particulate carriers

FIG. 5 growth of Beauveria bassiana on granular carriers

FIG. 6 cultivation of Beauveria bassiana against Bt185

Wherein "+" represents amphotericin B and "-" represents L B liquid medium.

FIG. 7 Effect of particle vectors on the insecticidal Activity of Bt and Beauveria bassiana

Wherein: different capital letters indicate significant differences at the 0.01 level.

Detailed Description

The present invention will be described in further detail with reference to examples.

The following raw materials were all commercially available

Example 1

1 materials and methods

1.1 test materials

1.1.1 granular carrier raw materials corn flour, peanut meal, calcium bentonite (400 meshes) and the like are purchased from Beijing Bingda biotechnology limited.

1.1.2 Bt soil granules for grub control screening [ J ]. Chinese biological control bulletin, 2017,33(1):70-78 ], having kanamycin resistance and expressing Green Fluorescent Protein (GFP) during proliferation, Bacillus thuringiensis Bt185[ Chen L i Y, Shu C, Shan Y, et al. Complex genome sequence of Bacillus thuringiensis Bt185, a bacterial Soilex gene construct [ Liuhuixia, Monoyum, Liuchun et al ] for testing pathogenic strains and insects Bacillus thuringiensis Bt185-GFP, which are isolated, prepared, stored in the laboratory, and stored in the laboratory, the plant protection of the Holly larva groups of the above-mentioned Coyus chinensis, which are provided by the research institute for protecting Holly larvae from the northern plant of the national academy of sciences, the research institute for protecting Holly larvae of the above-mentioned Scyphylla scientific plant.

1.1.3 Medium liquid L B medium and solid L B medium were purchased from Ku Laibop technologies, Beijing and solid PDA medium from American BD Co.

1.1.4 antibiotic kanamycin is purchased from Amresco company, 50mg/m L of aqueous solution, the kanamycin is filtered and sterilized by a 0.22-micron filter membrane when being prepared, the kanamycin is stored at the temperature of-20 ℃ and is added according to the proportion of 1 per thousand when being used, and soluble amphotericin B is purchased from Beijing Soilebao technology limited company, 2.5mg/m L, the kanamycin is stored at the temperature of-20 ℃ and is diluted by 1000 times by deionized sterile water when being used.

1.1.5 instruments and equipment for rapidly preparing aseptic basic granules, a single-screw puffing granulator with the model of DFM-80 and a granulation mould with the aperture of 3mm is adopted in the research and purchased from Xinxing mechanical factory in Hebei province; to detect Bt proliferation on the granules, an olympus fluoroscope model SZX16 was used in this study.

1.2 preparation of granules, measurement of diameter and weight and evaluation of form stability after Water absorption

Respectively mixing corn flour, peanut meal, bentonite and water according to different proportions (mass: volume) (table 1), uniformly stirring, puffing at high temperature (120 ℃) by a puffing machine, and cutting into granules; respectively taking 30 particles at random, measuring the diameter and the weight, and calculating the diameter and the weight of each particle; the particles are placed on the surface of 1.4 percent water agar, the morphological stability of the particles is evaluated through morphological change after water absorption, and finally the optimal particle carrier ratio is determined through screening.

TABLE 1 different proportions of the granule components and different water addition

1.3 detection of proliferation of biocontrol bacteria strain on granular carrier effective against Tabanus

1.3.1 detection of viable bacteria proliferation of Strain Bt185 on granular Carrier Strain Bt185-gfp is inoculated on L B agar plate, activated overnight, green monoclonal is picked up, transferred to 1/2L B liquid medium, cultured at 30 deg.C and 220r/min constant temperature until spore is released, further centrifuged to collect spore, washed with sterilized water to remove soluble protein, and further prepared into 1.3 × 10⁵And (3) inoculating 10 mu L Bt185-gfp bacterial liquid into each particle of the suspension of CFU/mu L, placing the particles on the surface of 1.4% water agar, culturing at constant temperature of 30 ℃, and detecting the fluorescence intensity of the particles after inoculating the bacterial liquid for 0 h, 48h and 96h in the sterile liquid by using a fluorescence stereomicroscope to judge the proliferation condition of the Bt 185.

1.3.2 Observation of growth of Beauveria bassiana on the granular carrier 1g of Beauveria bassiana powder was uniformly suspended in 10m L sterilized water, each granule was inoculated with 10 μ L bacterial liquid, the granules were placed on the surface of sterilized 1.4% water agar, cultured at 28 ℃ and the growth of Beauveria bassiana was observed.

1.4 antagonistic culture between Bt185 and Beauveria bassiana

Beauveria bassiana is inoculated on a PDA solid culture medium to grow, after conidia and conidia grow, a bacterial block with the diameter of 5mm is taken and placed in the center of a L B solid culture medium with the diameter of 90mm, three circular filter paper sheets with the sterilization diameter of 6mm are respectively placed at positions 25mm away from the center, 10 mu L of Bt185 bacterial liquid (or Bt185-gfp) and 10 mu L of amphotericin B and L B liquid culture mediums are respectively added as controls, and the result is detected after the culture is carried out for 7 days at the temperature of 28 ℃.

1.5 Effect of particulate vectors on the insecticidal Activity of Bt and Beauveria bassiana

1.5.1 preparation of Bt suspension Bt185 powder (1 g) was added to sterile water (50 m L) to make Bt suspension, which was stored in a refrigerator at 4 ℃ for further use.

1.5.2 preparation of Bt granule prepared in situ by sucking 20 μ L of prepared Bt powder suspension, adding onto the surface of a granular carrier, and making into granule of granular carrier + Bt.

1.5.3 preparation of Bb suspension was prepared by adding 1g of Bb powder to 50m L of sterilized water and storing in a refrigerator at 4 ℃ until use.

1.5.4 Bb granule preparation the Bb powder suspension is sucked by 20 μ L and added to the surface of a particle carrier to prepare the granule of particle carrier + Bb, which is prepared on site.

1.5.5 preparation of Bt and Bb granules prepared in situ by pipetting 10. mu. L of Bt suspension and Bb suspension respectively, adding onto the surface of a granule, and making into granules of granular carrier + Bt + Bb.

1.5.6 determination of insecticidal Activity of granule on Holotrichia parallela larva

The method comprises the steps of putting potato strips (5mm × 5mm × 40mm) serving as feed into a 6-hole bioassay board, treating according to a method shown in table 2, covering soil with the water content of 20% on each bioassay hole, and feeding 1 head of healthy 7-10D-age dark black gill chafer larva with uniform individual size into an artificial climate box with the temperature of (28 +/-1) ° C, the light cycle of 16L: 8D and the relative humidity of 70% -80% for 7D, counting the number of live insects and the number of dead insects respectively, and calculating and correcting the death rate after feeding for 7D in the artificial climate box with the temperature of (28 +/-1) ° C, the light cycle of 16L: 8D and the relative humidity of 70% -80%.

TABLE 2 preparation of granules for bioassay

2 results and analysis

2.1 preparation of the particulate support, measurement of the diameter and weight and evaluation of the morphological stability after Water absorption

In order to screen out the best formulation of the pellet carrier, the study first formulated the test materials as in table 1, prepared the pellets by single-screw spiral puffing equipment, and counted the color, size and density of the pellets. The results show that the proportion of corn flour, peanut meal and bentonite is different, and the size and color of the particles after puffing are different; the density of the particles is gradually increased along with the increase of the content of the peanut meal; the 20% add of water was slightly less than the 15% add of water (fig. 1).

The diameter and weight of the granules of different formulations were further accurately measured, and the results showed that the diameter and weight of the granules both showed a tendency to decrease as the content of peanut meal increased (fig. 2, fig. 3). In the current agricultural production, machines special for spreading fertilizer particle products such as urea and the like exist, so the particle carrier screening is carried out according to the diameter specification (2.0-4.8 mm) of urea particles in the research, and the results show that the diameters of three particles (C, D, E in figure 1) of corn flour, peanut meal and bentonite in the ratio of 1:1:0, 1:3:0 and 1:3:2 meet the requirements. In addition, the structural stability of different granular carriers under the water absorption condition is measured, the granules are placed on the surface of water agar and are observed after being swelled for 24 hours, the granules with high corn meal content and the granules added with bentonite are not cracked (A, B, E in figure 1), and in the preparation process of the granules, the extrusion and swelling process of the granules with 20% of water addition is smoother, and the machine is not easy to damage. By combining the index analysis, the optimal particle carrier proportion of the corn flour, the peanut meal and the bentonite is finally determined, wherein the proportion of the corn flour, the peanut meal and the bentonite is 1:3:2, and the water addition amount of 20% is used for preparing the particle carrier for the next research.

2.2 analysis of proliferation of Bt185 on particulate Supports

To examine the proliferation of Bt on the particulate support, this study performed proliferation assays using a Bt strain (Bt185-gfp) effective against Holotrichia parallela larvae. The results show that the fluorescence on the particulate carriers increases gradually as the incubation time increases, as detected by the fluoroscope; when the Bt185-gfp bacterial liquid is just inoculated, no obvious fluorescence can be observed; after 48h of incubation, significant fluorescence was observed; when the culture was continued for 96 hours, the fluorescence intensity further increased (FIG. 4). The above results indicate that Bt can be propagated on the particulate supports prepared in this study.

2.3 Observation of growth of Beauveria bassiana on granular Carrier

To examine the growth of beauveria bassiana on the particles, this study inoculated beauveria bassiana suspension onto the surface of the particles, and the particles were placed on a water agar surface for observation. The results show that beauveria bassiana can utilize the granular carrier to carry out vegetative germination and growth, mycelia grow to 5-10mm after 72h, and spores can be formed after further culture (figure 5).

2.4 antagonistic culture analysis between Bt185 and Beauveria bassiana

In order to evaluate whether the Bt and beauveria bassiana have mutual inhibition, the opposite culture experiment of the beauveria bassiana and the Bt185 strain is carried out in the research. The result shows that the mycelium of the beauveria bassiana grows from the center of the culture medium to the periphery in a diffused way, Bt185 has no inhibition effect on the mycelium of the beauveria bassiana, and an obvious inhibition zone is formed around amphotericin B; meanwhile, normal growth of Bt185 was observed from the bottom of the dish, with the formation of lawn around it (FIG. 6). The results show that Bt185 and beauveria bassiana have no antagonism, and the two biocontrol strains can be used synergistically.

2.5 Effect of particulate vectors on the insecticidal Activity of Bt and Beauveria bassiana

In order to analyze the influence of the particle carriers on the insecticidal effect of Bt and beauveria bassiana, the insecticidal activity of five samples of Bt185 powder, Bb powder, particle carrier + Bt185, particle carrier + Bb and particle carrier + Bt + Bb on larvae of 7-10 days old Holotrichia parallela is determined in the research. The results show that the granular carrier can significantly improve the insecticidal action of Bt and beauveria bassiana, and the combined use of the granular carrier and two biocontrol strains can further improve the insecticidal effect (fig. 7).

Example 2 further screening of particulate carrier formulations:

respectively mixing corn flour, peanut meal, bentonite and water (20 percent of raw material powder) according to different proportions (Table 3), uniformly stirring, extruding and puffing at high temperature by a puffing machine into strips, and cutting into spherical particles by a cutter; respectively taking 30 particles at random, measuring the diameter and the weight, and calculating the diameter and the weight of each particle; the granules were placed on the surface of 1.4% water agar, and the morphological stability of the granules was evaluated by morphological change after water absorption and agitation after placing in water, while the proliferation of the biopesticide granules with Bt185 powder adsorbed thereto in soil was determined.

TABLE 3 particle fraction screening

The single-rod spiral puffing machine is favorable for puffing the granules with different components, and the granules can be puffed and molded when the corn flour content is 17% -100%, the peanut meal content is 0% -75%, and the bentonite content is 0-33%. The granules without corn flour can not be formed by puffing, and the granules with too much bentonite can not be formed.

In order to meet the specification of granules sowed by modern agricultural machinery, the research screens the expanded and molded granules according to the diameter (2.0-4.8 mm) of urea, and the results of particle diameter measurement show that the content of corn flour is 17-50%, the content of peanut meal is 50-75%, and the content of bentonite is within the range of 0-33%, and the diameter meets the specification. Although the diameter of the die selected by the single-rod spiral bulking machine is 3mm, the grain diameter is expanded due to the bulking effect, and particularly for the components with the serial numbers 1 and 2, the bulking effect is better due to the larger amount of the corn flour, but the pipeline can be blocked by selecting a smaller die. Therefore, a die diameter of 3mm is preferred for expansion.

In actual agricultural application, the granules absorb moisture when applied to soil, so the form stability of the granules after being exposed to water is considered. The research tests the water absorption of the expanded and formed particles and tests the shape change of the particles after the particles are put into water and stirred, and the results show that the particles with high corn flour content do not crack after absorbing water and the shape is still complete after being stirred in water, but the particles do not crack when the bentonite content is in the range of 20-33%.

According to the proliferation detection result of Bt viable bacteria, the content of corn flour is 17-30%, the content of peanut meal is 50-60%, the content of bentonite is within the range of 20-33%, and the proliferation multiple of Bt viable bacteria is the highest.

Therefore, the optimal component proportion is that the content of corn flour is 17-30%, the content of peanut meal is 50-60%, and the content of bentonite is 20-33%.

Claims

1. A particle carrier of a biological insecticide comprises the following components in percentage by mass: 15-40% of corn flour, 50-60% of peanut meal and 10-35% of bentonite; the particle carrier is prepared by the following method:

2. The particulate carrier of claim 1, wherein: 17-30% of corn flour, 50-60% of peanut meal, 20-33% of bentonite and 20% of water added as raw material powder.

3. The particulate carrier of claim 2, wherein: 17% of corn flour, 50% of peanut meal and 33% of bentonite.

4. A particulate carrier according to any one of claims 1-3 wherein: the bentonite is calcium bentonite; the particle size of the bentonite is 80-400 meshes.

5. A process for preparing the granular carrier of biologic insecticide as claimed in claim 1-4, which includes such steps as proportionally mixing corn powder, peanut dregs and bentone, mixing, adding water (15-20 wt.%), mixing, and single-screw puffing at 120 deg.C and 3mm in diameter.

6. A biopesticide granule comprising the granule carrier according to any one of claims 1 to 4 and a biopesticide adsorbed on the granule carrier.

7. The biopesticide granule of claim 6, the biopesticide being Bt bacteria and/or Beauveria bassiana.

8. The biopesticide granule of claim 6, the biopesticide being Bt185 and/or Beauveria bassiana.

9. Use of the biopesticide granule of any one of claims 6 to 8 for controlling agricultural underground pests.

10. A process for producing biopesticide particles according to any one of claims 6 to 8, which comprises suspending a biopesticide in water, adding the particle carrier according to any one of claims 1 to 4 to the suspension, or spraying the biopesticide suspension onto the particle carrier, so that the surface of the particle carrier is uniformly adsorbed with the biopesticide.