Method for breeding Noctuid black egg bee subculture population by taking corcyra cephalonica eggs as hosts

Abstract

The invention belongs to the technical field of agricultural biology, and relates to a method for cultivating a subculture population of noctuid black egg bees by taking corcyra cephalonica eggs as hosts, which comprises the following steps of: taking male adult bees of the noctuid black egg bees as initial breeding bees; the method comprises the following steps: selecting corcyra cephalonica eggs, rinsing the corcyra cephalonica eggs in a sodium hypochlorite aqueous solution, attaching the corcyra cephalonica eggs to kraft paper, stuffing the kraft paper into a feeding cylinder, introducing initial breeding bees of the noctuid black egg bees, taking out the kraft paper on which the corcyra cephalonica eggs are parasitized after 1-2 days, and screening out male adult bee individuals as primary breeding bees after the noctuid black egg bees are subjected to eclosion; and repeating the steps to screen for 3-5 generations to obtain the subculture population of the black ovum noctuid. According to the method, the noctuid black egg bees collected in the field serve as a basic population, through biological treatment of the noctuid black egg bees and corcyra cephalonica eggs, breeding of a small number of generations is conducted, the physiological adaptability of the noctuid black egg bees to the non-natural host corcyra cephalonica is rapidly improved, and the survival rate of the corcyra cephalonica is increased. And a Noctuid black egg bee subculture breeding population independent of natural host noctuidae insects is established indoors.

Description

Technical Field

[0001] The invention belongs to the field of agricultural biotechnology and relates to a method for indoor cultivation of Spodoptera black egg wasp, a natural enemy of fall armyworm, by biologically treating Spodoptera black egg wasp and rice moth eggs, and specifically relates to a method for cultivating a succession population of Spodoptera black egg wasp using rice moth eggs as hosts. Background Art

[0002] Fall armyworm (Spodopterafrugiperda), belonging to the genus Spodoptera of the family Noctuidae in the order Lepidoptera, is a major dangerous migratory pest that poses a serious threat to agricultural production. Since the invasion of fall armyworm in January 2019, it has gradually spread to 26 provinces and regions across the country due to its migratory habits. In 2019 alone, the maize area affected was about 1.065 million hm2. 2 , and caused damage to 14 other crops such as sugarcane, sorghum, millet and wheat, posing a severe prevention and control situation.

[0003] According to the classic biological control theory, using natural enemies to control fall armyworm is an effective way. Telenomus remus belongs to the family of Hymenoptera, and is an important parasitic natural enemy of many Lepidoptera Noctuidae insects in the egg stage. Because the bee has a high parasitic ability and can reproduce in large numbers, it has become one of the main biological factors for controlling Lepidoptera Noctuidae pests. Nowadays, Telenomus remus is widely used in the control of fall armyworm all over the world. Through molecular identification of eggs and population surveys in South Africa, East Africa and West Africa, it is shown that Telenomus remus is an important egg parasitoid of fall armyworm in Africa, and can be used as an important biological control parasitic wasp for the control of fall armyworm.

[0004] In my country, eggs of Noctuidae insects are important natural hosts of Spodoptera exigua in the field. At the same time, Spodoptera exigua is also one of the important parasitic wasps for controlling Spodoptera litura (Spodopteraliture) and Spodoptera exigua in the field. The current mainstream technical path for the expansion of Spodoptera exigua is to mass-produce natural hosts, namely, Spodoptera exigua. However, at present, given the high temperature and high humidity indoor environment required for the production of Noctuidae insects, which leads to problems such as infection by insect polyhedrosis virus and microsporidia, and is limited by the egg-laying capacity, and the characteristics of rapid development and hatching of Spodoptera eggs, it is difficult to accumulate a certain scale and number of egg sources with consistent physiological indicators under indoor conditions for the expansion of Spodoptera exigua, resulting in the domestic production of Spodoptera exigua still being maintained in the small-scale breeding range. Therefore, the establishment of a large-scale breeding technology system for Spodoptera exigua in my country is of great significance for the long-term prevention and control of Spodoptera pests.

[0005] As a storage pest, the rice moth (Corcyracephalonica) is considered to be an important alternative host for the propagation of natural enemy parasitic wasps due to its relatively dry breeding environment and low-cost coarse grain feed. In my country, a mature and complete production technology system and scale have been formed in the application of rice moth to propagate the natural enemy trichogrammatid wasps. However, when trying to breed the black-egg wasp of the noctuid armyworm with rice moth eggs, it is still necessary to simultaneously establish a production line or mass-produce Noctuidae insects to solve the problem of the adaptability of the black-egg wasp of the noctuid armyworm to rice moth eggs. As a result, the breeding steps of the black-egg wasp of the noctuid armyworm are complicated, manual operations are frequent, and material costs are high, making it difficult to breed on a large scale, and it is also impossible to effectively change the parasitic nature of the black-egg wasp of the noctuid armyworm to rice moth eggs. Summary of the invention

[0006] The invention aims to provide a method for cultivating a succession population of Spodoptera exigua using rice moth eggs as hosts. The method improves the adaptability of the adult Spodoptera exigua to rice moth eggs by successively treating rice moth eggs and adult Spodoptera exigua, breaks away from the parasitic dependence of the Spodoptera exigua on eggs of natural hosts, Noctuidae, such as fall armyworm, fall armyworm, beet armyworm and other insects, and realizes population breeding on rice moth eggs of wax moth family. The method quickly improves the parasitic level of the Spodoptera exigua to non-natural hosts, namely, rice moth eggs, by cultivating a small number of generations, such as 3 to 5 generations. The succession population of the Spodoptera exigua using rice moth eggs as hosts is obtained. The method has biological parameters such as relatively high parasitism rate and fecundity, and at the same time maintains good parasitic effect on fall armyworm eggs, thereby providing a large number of natural enemy parasitic bee sources for biological control of fall armyworm.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] A method for cultivating a subgeneration population of Noctuidae black egg wasp using oryzae moth eggs as hosts comprises the following steps:

[0009] Step S1: Noctuidae black egg wasp treatment

[0010] S11: Collect eggs of Spodoptera exigua from natural hosts in the wild, wait for them to emerge as adult bees and use them as the initial population; without providing any nutrition or water, keep the adult bees in a hungry and thirsty state for 6 to 24 hours;

[0011] S12: Select strong adult bee individuals from the initial population as initial breeding bees.

[0012] Step S2: Rice moth egg treatment

[0013] S21: Select rice moth eggs with an egg age of 2 to 6 days, rinse them in a sodium hypochlorite aqueous solution for 10 to 30 seconds, then take them out and dry them in an indoor environment; rinsing the rice moth eggs with a sodium hypochlorite aqueous solution can not only have the effect of disinfection and sterilization, but also stabilize the surface structure of the rice moth eggs, which is conducive to the subsequent parasitic laying of eggs by the noctuid black egg wasp.

[0014] S22: evenly apply 1-8% polyvinyl alcohol solution on kraft paper, then spread rice moth eggs on the kraft paper containing the polyvinyl alcohol solution, hang the kraft paper in an indoor environment, and wait for the solution to dry. The polyvinyl alcohol solution can make the rice moth eggs adhere to the kraft paper and keep the rice moth eggs moist.

[0015] Step S3: Cultivation of subgeneration populations of Noctuidae black egg wasps

[0016] S31: With the kraft paper with the rice moth eggs attached facing outward, the kraft paper is rolled into a cylindrical tube smaller than the diameter of the feeding tube, and a small amount of pure water is sprayed to wet the surface of the eggs;

[0017] S32: inserting the kraft paper cylinder into the light-transmitting cylindrical feeding cylinder, and introducing the initial seed bees of the noctuid black egg wasp;

[0018] S33: putting nutrients into the feeding tube as supplementary nutrition for the noctuid black egg wasp, and taking out the kraft paper on which the rice moth eggs have been parasitized after 1 to 2 days;

[0019] S34: After the noctuid black egg wasps parasitizing the rice moth eggs on the kraft paper emerge, starve them for 6 to 24 hours, and select the strong adult bees as the first generation of breeding bees;

[0020] S35: Repeat the above steps to perform 3 to 5 generations of screening to obtain a subgeneration population of Spodoptera exigua that uses the eggs of the cypripedium oryzae as hosts for breeding.

[0021] Furthermore, in step S11, the number of adult bees in the initial population is not less than 10,000, and the population stocking density is 10 to 15 bees / 100 cm 3 .

[0022] Furthermore, in step S12, the number of the initial breeding bees is not less than 5,000, and the male-female ratio is 1 to 2:1.

[0023] Furthermore, in step S21, the temperature of the sodium hypochlorite aqueous solution is 10-15° C. and the concentration is 0.05-1%.

[0024] Furthermore, in step S32, the ratio of the number of adult bees of the initial breeding bees to the number of rice moth eggs is between 1:5 and 1:10.

[0025] Furthermore, in step S33, the nutrient is a cotton swab dipped in honey puree, and the honey puree refers to unprocessed honey taken directly from a beehive.

[0026] Furthermore, in step S34, the number of adult bees of the first generation of bees is not less than 5,000, and the male-female ratio is 1 to 2:1.

[0027] Beneficial effects of the present invention:

[0028] 1. The present invention uses the black egg wasps of the noctuid armyworm collected in the wild and parasitizing on natural hosts such as eggs of the fall armyworm, eggs of the cutworm and eggs of the beet armyworm as the basic population. Under the condition of a limited number of wild parasitic wasps, the black egg wasps of the noctuid armyworm and eggs of the rice moth are biologically treated to cultivate a small number of generations, thereby quickly improving the physiological adaptability of the black egg wasps of the noctuid armyworm to the non-natural host rice moth, and establishing a succession breeding population of the black egg wasps of the noctuid armyworm that is independent of the natural host Noctuidae insects indoors.

[0029] 2. The method of cultivating the black egg wasp of Spodoptera oryzae using the eggs of rice moth as the host is simple, and the eggs and insect homogenate of Noctuidae insects, and other materials such as Noctuidae insects and attached derivatives that must be used in the breeding process are completely eliminated, and the accidents such as polyhedrosis virus infection, microsporidia infection, etc., which lead to the indoor epidemic outbreak and interruption of production in the natural enemy factory due to the production of Noctuidae insects are avoided. The operation process is simple and the method is reliable.

[0030] 3. The rice moth of the present invention is a storage pest, and it can be raised on a large scale under indoor conditions by regularly putting into rough grain feed. In addition, it has a short life cycle and strong reproductive capacity, and can continuously provide eggs throughout the year for the black egg wasp of the noctuid armyworm to parasitize and produce the next generation of parasitic wasp populations, and it can plan and select the release control opportunity with ease according to the occurrence of field Noctuidae insects. It promotes the quantification, planning and intensification of the black egg wasp of the noctuid armyworm to control the greedy fall armyworm, and is also more conducive to the formulation and implementation of various comprehensive control measures such as insecticide control and chemical trapping. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are further described in detail below in conjunction with the examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0032] 1. Cultivation of successive generations of noctuid black egg wasps

[0033] Embodiment 1

[0034] (1) Treatment of Noctuidae black egg wasp

[0035] a. Collect eggs of Noctuidae from natural hosts in the wild and let them hatch in cages as the initial population. The number of adult bees is about 15,000, and the population density is 10 / 100cm 3 ;

[0036] b. After the black egg wasps of the noctuid moth emerge, no nutrition or water is provided to the adult wasps, causing them to starve and thirst for 6 hours;

[0037] c. Discard adult bees with weak flying ability or dead individuals, and select a population of 5,000 strong individuals as the initial breeding bees, with a male-female ratio of 1:1.

[0038] (2) Treatment of rice moth eggs

[0039] a. Select 3-day-old rice moth eggs;

[0040] b. Take 0.05% sodium hypochlorite aqueous solution and heat to 15 ℃, quickly rinse the rice moth eggs for 10s and remove them, and dry them in indoor environment;

[0041] c. Apply 3% polyvinyl alcohol solution evenly on the kraft paper, then spread the rice moth eggs evenly on the kraft paper containing the polyvinyl alcohol solution, hang the kraft paper in an indoor environment, and wait for the solution to dry.

[0042] (3) Cultivation of successive generations of Noctuidae black egg wasps

[0043] a. Make the kraft paper attached to the rice moth eggs face outward, curl the kraft paper into a cylindrical tube smaller than the diameter of the feeding tube, and spray a small amount of pure water to moisten the surface of the eggs;

[0044] b. The kraft paper cylinder is inserted into a light-transmitting cylindrical feeding tube, and the initial species of noctuid black egg bees are introduced, with the ratio of adult bees to rice moth eggs being 1:10;

[0045] c. Put several cotton swabs soaked in puree honey as supplementary nutrition for the black egg wasp population of Spodoptera exigua, and take out the kraft paper that has been parasitized by the rice moth eggs after 24 hours;

[0046] d. After the black egg wasps of the noctuid on kraft paper emerged and were starved for 6 hours, 5,000 strong individuals were selected as the first generation of bees, with a male-female ratio of 1:1;

[0047] e. Repeat the above steps for 7 generations of screening to obtain the successive generation population of Spodoptera exigua using oryzae eggs as hosts for breeding.

[0048] Embodiment 2

[0049] (1) Treatment of Noctuidae black egg wasp

[0050] a. Collect eggs of Spodoptera exigua from natural hosts in the wild, and let them hatch in cages as the initial population. The number of adult bees is about 11,000, and the population stocking density is 15 / 100cm3;

[0051] b. After the black egg wasps of the noctuid armyworm emerge, they are not provided with any nutrition or water, leaving the adult wasps hungry and thirsty for 24 hours;

[0052] c. Discard adult bees with weak flying ability or dead individuals, and select a population of 5,000 strong individuals as the initial breeding bees, with a male-female ratio of 2:1.

[0053] (2) Treatment of rice moth eggs

[0054] a. Select 6-day-old rice moth eggs;

[0055] b. Take a 1% aqueous solution of sodium hypochlorite and heat it to 10 ° C, quickly rinse the rice moth eggs for 30 seconds and remove them, and dry them in an indoor environment;

[0056] c. Evenly apply 8% polyvinyl alcohol solution on the kraft paper, then spread the rice moth eggs evenly on the kraft paper containing the polyvinyl alcohol solution, hang the kraft paper in an indoor environment, and wait for the solution to dry.

[0057] (3) Cultivation of successive generations of Noctuidae black egg wasps

[0058] a. Make the kraft paper attached to the rice moth eggs face outward, curl the kraft paper into a cylindrical tube smaller than the diameter of the feeding tube, and spray a small amount of pure water to moisten the surface of the eggs;

[0059] b. Insert the above-mentioned kraft paper cylinder into the light-transmitting cylindrical feeding tube, introduce the initial species of noctuid black egg bees, and the ratio of adult bees to rice moth eggs is 1:5;

[0060] c. Put several cotton swabs soaked in puree honey as supplementary nutrition for the black egg wasp population of Spodoptera exigua, and take out the kraft paper that has been parasitized by the rice moth eggs after 48 hours;

[0061] d. After the black egg wasps of the noctuid on kraft paper have emerged and starved for 24 hours, 5,000 strong individuals are selected as the first generation of bees, with a male-female ratio of 2:1;

[0062] e. Repeat the above steps for 5 generations of screening to obtain the subgeneration population of Spodoptera exigua using oryzae eggs as hosts for breeding.

[0063] 2. Effect of the cultivation of the successive population of the noctuid black egg wasp

[0064] Randomly take the 1st, 3rd, 5th and 7th generations of Example 1 and the 1st, 3rd and 5th generations of Example 2, no less than 600 eggs, three replicates in total, and place them in different glass tubes, record the number of parasitized eggs and the number of bee eggs, and calculate the egg parasitism rate and bee emergence rate. The results are shown in Table 1.

[0065] Egg parasitism rate = (number of parasitized eggs / total number of eggs) × 100%

[0066] Emergence rate = (number of eggs emerging / number of parasitized eggs) × 100%

[0067] Table 1 Parameters for breeding the successive population of Noctuidae black egg wasp

[0068]

[0069]

[0070] As can be seen from Table 1, the method of using the present invention to cultivate the black egg wasp of Noctuidae as the host to succeeding population of Noctuidae islet with rice moth egg as the host, the parasitism ratio of the black egg wasp of Noctuidae to rice moth egg of 1:10 is set in Example 1, and the parasitism rate of rice moth egg becomes a rising trend in F1 generation, F3 generation, F5 generation, and F7 after parasitizing rice moth from wild population, which is respectively 33.14%, 41.13%, 51.12% and 55.61%, showing that most of rice moth egg grains can be parasitized by the black egg wasp of Noctuidae after processing, and the black egg wasp emergence rate of the parasitized rear egg grains can reach 53.23%, 64.13%, 84.12% and 85.74% respectively. The parasitic ratio of the black egg wasp of Noctuidae and rice moth egg of 1: 5 is set in embodiment two, after the wild population parasitizes rice moth, F1 generation, F3 generation and F5 generation, it becomes a rising trend to the parasitism rate of rice moth egg, which is respectively 34.18%, 55.12% and 56.34%, showing that most of rice moth egg grains can be parasitized by the black egg wasp of Noctuidae after the inventive method is processed, and the black egg wasp of Noctuidae of the rear egg grains parasitized can reach 49.23%, 75.9% and 85.12% respectively. The above example shows that most of the rice moth egg grains parasitized can hatch the black egg wasp of Noctuidae, and after the succession of more than 3 generations, the adaptability of the black egg wasp of Noctuidae to rice moth egg is effectively improved. Therefore, the method can be used for a large number of expansion of the black egg wasp of Noctuidae, and the consistent bee source of sufficient physiological indicators is provided for field biological control.

[0071] 3. Parasitic effect of the successive population of Spodoptera exigua on the fall armyworm

[0072] The 5th and 7th generations of rice moth eggs of Example 1 of the present invention and the 3rd and 5th generations of Example 2 were used to hatch no less than 100 black egg bees of the noctuid armyworm, and 10 times the eggs of the fall armyworm 0-24h were added respectively, and three repetitions were made, and the number of parasitized eggs and the number of bee eggs were recorded, and the egg parasitism rate and bee emergence rate were calculated. The results are shown in Table 2.

[0073] Egg parasitism rate = (number of parasitized eggs / total number of eggs) × 100%

[0074] Emergence rate = (number of eggs emerging / number of parasitized eggs) × 100%

[0075] Table 2 The parasitic effect of the successive population of the noctuid black egg wasp on the fall armyworm

[0076]

[0077] As can be seen from Table 2: the parasitism rate of the noctuid black egg wasp cultivated by the present invention using rice moth eggs as hosts to the fall armyworm eggs is 90.04%, 89.23%, 91.18% and 92.13%, respectively, showing that the noctuid black egg wasp after the rice moth is expanded has a higher parasitism level to the fall armyworm eggs, and the noctuid black egg wasp emergence rate of the parasitized eggs can reach 92.84%, 93.94%, 91.32% and 92.04%, respectively, indicating that most of the parasitized eggs can hatch the noctuid black egg wasp. Therefore, the noctuid black egg wasp population expanded by this method still has a good parasitism level to the fall armyworm eggs, achieving the effect of biological control of the fall armyworm.

[0078] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for cultivating a succession population of Noctuidae black egg wasps using oryzae eggs as hosts, characterized in that: The following steps are involved: Step S1: Noctuidae black egg wasp treatment S11: Collect eggs of Spodoptera exigua from natural hosts in the wild, wait for them to emerge as adult bees and use them as the initial population; without providing any nutrition or water, keep the adult bees in a hungry and thirsty state for 6 to 24 hours; S12: Select strong adult bees from the initial population as initial bees; Step S2: Rice moth egg treatment S21: selecting 2- to 6-day-old rice moth eggs, rinsing them in a sodium hypochlorite aqueous solution for 10 to 30 seconds, taking them out, and drying them in an indoor environment; S22: evenly applying a 1-8% polyvinyl alcohol solution on kraft paper, then spreading rice moth eggs evenly on the kraft paper containing the polyvinyl alcohol solution, hanging the kraft paper in an indoor environment, and waiting for the solution to dry; Step S3: Cultivation of subgeneration populations of Noctuidae black egg wasps S31: With the kraft paper with the rice moth eggs attached facing outward, the kraft paper is rolled into a cylindrical tube smaller than the diameter of the feeding tube, and a small amount of pure water is sprayed to wet the surface of the eggs; S32: inserting the kraft paper cylinder into the light-transmitting cylindrical feeding cylinder, and introducing the initial seed bees of the noctuid black egg wasp; S33: putting nutrients into the feeding tube as supplementary nutrition for the noctuid black egg wasp, and taking out the kraft paper on which the rice moth eggs have been parasitized after 1 to 2 days; S34: After the noctuid black egg wasps parasitizing the rice moth eggs on the kraft paper emerge, starve them for 6 to 24 hours, and select the strong adult bees as the first generation of breeding bees; S35: Repeat the above steps to perform 3 to 5 generations of screening to obtain a subgeneration population of Spodoptera exigua that uses the eggs of the cypripedium oryzae as hosts for breeding.

2. The method for cultivating the successive generation population of Noctuidae black egg wasps using oryzae eggs as hosts according to claim 1, characterized in that: In step S11, the number of adult bees in the initial population is not less than 10,000, and the population stocking density is 10 to 15 bees / 100 cm 3 .

3. The method for cultivating the successive generation population of Noctuidae black egg wasps using oryzae eggs as hosts according to claim 1, characterized in that: In the step S12, the number of the initial breeding bees is not less than 5,000, and the male-female ratio is 1 to 2:

1.

4. The method for cultivating the successive generation population of Noctuidae black egg wasps using oryzae eggs as hosts according to claim 1, characterized in that: In the step S21, the temperature of the sodium hypochlorite aqueous solution is 10-15° C. and the concentration is 0.05-1%.

5. The method for cultivating the successive generation population of Noctuidae black egg wasp using oryzae eggs as hosts according to claim 1, characterized in that: In the step S32, the ratio of the number of adult bees of the initial breeding bees to the number of rice moth eggs is between 1:5 and 1:

10.

6. The method for cultivating the successive generation population of Noctuidae black egg wasps using oryzae eggs as hosts according to claim 1, characterized in that: In step S33, the nutrient is a cotton swab dipped in raw honey, and the raw honey refers to unprocessed honey taken directly from a beehive.

7. The method for cultivating the successive generation population of Noctuidae black egg wasp using oryzae eggs as hosts according to claim 1, characterized in that: In step S34, the number of adult bees of the first generation of bees is not less than 5,000, and the male-female ratio is 1 to 2:1.

Images