Method for field prevention and control of fall webworms by using brachycera majorana

Abstract

The invention relates to the technical field of biological prevention and control, and particularly discloses a method for field prevention and control of fall webworms by using brachycera pubescens, which comprises the following steps: collecting and domesticating brachycera pubescens species, raising hosts in a standardized manner, propagating brachycera pubescens, and regularly rejuvenating populations. And releasing the hyphantria cunea in a pupal stage at a density of 50-250 per mu under a suitable environmental condition. According to the method provided by the invention, by optimizing the bee pupae ratio and the field release density, the field parasitism rate of the brachycera majorana is remarkably increased, the highest parasitism rate can reach 62.5% and is far higher than the natural parasitism rate, and a new effective way is provided for green and sustainable prevention and control of fall webworms.

Description

Technical Field

[0001] This invention relates to the field of biological control technology, specifically to a method for controlling the fall webworm in the wild using the large-legged wasp. Background Technology

[0002] American white moth ( Hyphantria cunea (Order: Noctuidae; Subfamily: Arctiinae; Genus: White Moth) Hyphantria The fall webworm (Pterygota julibrissin) is an internationally quarantine pest. It is omnivorous, has a high reproductive rate, and its larvae and pupae can spread over long distances via host plants and cargo packaging, making it difficult to control. In recent years, the use of natural enemy insects to control the fall webworm has achieved significant results; for example, the use of *Paragonimus westermani* during the pupal stage of the fall webworm has yielded remarkable results. Chouioia cunea Control measures can rapidly reduce the number of the next generation of adults. Natural enemy insects have become a better option for controlling the fall webworm. However, currently only the parasitoid wasp *Tetranychus zhoui* can be used on a large scale. Other wasp species have low parasitism rates and are difficult to achieve control effects. Therefore, it is urgent to develop a method to control the fall webworm by increasing the parasitism rate of wasp species. Summary of the Invention

[0003] This invention provides a method for controlling the fall webworm (Trichoderma gracilis) in the field using the parasitoid wasp *Trichoderma gracilis*. The method significantly improves the field parasitism rate of *Trichoderma gracilis* by optimizing the wasp-pupa ratio and release density, reaching a maximum of 62.5%, far exceeding the natural parasitism rate. This provides a new and effective approach for the green and sustainable control of the fall webworm.

[0004] This invention provides a method for controlling the fall webworm in the field using the large-legged wasp, comprising the following steps: Cultivate a large number of legged wasps until they emerge as adults to obtain a seed stock for future use; Rear the fall webworms until the larvae pupate, and collect the fall webworm pupae for later use; Select mated female and male bees from the bee population source, parasitize the American white moth pupa, and raise the parasitized pupae until the offspring of the large-legged wasp emerge. After emergence, the large-legged wasp is propagated. After the large-legged wasp has been propagated for 4 to 6 generations, the indoor wasp species and the newly collected wild wasp species are mixed and mated at a ratio of 3 to 5:1, and then the American white moth pupa is used for parasitism to obtain a revitalized population. Select robust, mated adult wasps from the rejuvenated population as the release species and release them in areas severely affected by the fall webworm, at the early stage of the fall webworm pupal stage or the early stage of its occurrence.

[0005] The method provided by this invention significantly improves the field parasitism rate of the American white moth by optimizing the ratio of wasp pupae and the release density in the wild, reaching up to 62.5%, which is far higher than the natural parasitism rate. This provides a new and effective approach for the green and sustainable control of the American white moth.

[0006] Furthermore, the amplification is as follows: Female and male giant wasps with large legs that have emerged 1 to 3 days ago were placed in a mating container at a ratio of 1:2 to 4 for 7 days, and provided with water and honey. After mating, female wasps and American white moth pupae were placed in a parasitizing container at a ratio of 1:10~30. After the parasitism ends, the adult wasps are removed, and the parasitized pupae are cultured until the offspring of the large-legged wasps emerge.

[0007] Furthermore, the temperature at which the parasite resides is 20℃~30℃.

[0008] Furthermore, the light / dark ratio of the parasite is 14~18 / 6~10, and the light intensity is 4600 lx~5000 lx.

[0009] Furthermore, the humidity of the parasite is 55% to 65%.

[0010] Furthermore, the parasitic duration is 22 h to 26 h.

[0011] Furthermore, the parasitic container includes a can and a lid. The can has several first circular holes on its side wall, and the lid has a second circular hole in the center. The outer sides of the first and second circular holes are covered with mesh.

[0012] Furthermore, the water is replenished through a water container; the water container includes a box body and a box lid, and a third circular hole is provided in the center of the box lid. A cylindrical cotton swab is provided in the third circular hole, one end of the cylindrical cotton swab is located on the outside of the box lid, and the other end passes through the third circular hole and abuts against the inside of the bottom of the box body.

[0013] Furthermore, the ambient temperature during the release of the bee species is 20℃~30℃, and the humidity is 55%~65%.

[0014] Furthermore, the bee species release density is 50 to 250 bees per acre.

[0015] This invention also provides a method for increasing the parasitism rate of the American white moth pupa by the large-legged wasp.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, by optimizing the ratio of wasp pupae and the release density in the wild, successfully increased the parasitism rate of the fall webworm by the large-legged wasp from 6.6% to 62.5%, directly solving the technical bottleneck of limited natural enemies and single biological control methods for the fall webworm. It provides a new, alternative, or supplementary biological control option for the integrated management of the fall webworm.

[0017] This invention, through systematic parasitic condition screening experiments, established key optimization parameters for the propagation of the giant white moth wasp: a wasp-to-pupa ratio of 1:10 (1 female wasp to 10 American white moth pupae) was determined to be the optimal parasitism rate (77.35%); 25℃ was determined to be the most suitable parasitism temperature, at which the parasitism rate of each wasp-to-pupa ratio was optimal; and the influence of wasp density was clarified. The experiments showed that while increasing the number of female wasps increased the total number of parasites, the average number of parasites per wasp decreased, revealing a disturbance effect within the wasp colony. This finding provides a scientific basis for guiding the rational control of inoculated wasp density and optimizing resource allocation in large-scale breeding.

[0018] This invention, through field release trials in two locations, demonstrates that releasing the giant wasp *Microsorum pteropus* significantly increases the field parasitism rate of *Ailuropoda spp.* pupae. At a high density of 250 wasps per acre, the field parasitism rate reached a maximum of 62.5%, far exceeding the natural parasitism rate observed in field surveys (approximately 6.6%). It clarifies that release should occur at the early stage of the *Ailuropoda spp.* pupal stage or in the early stages of the disease to ensure sufficient host pupa resources. An ambient temperature of 20℃~30℃ and humidity of 55%~65% are chosen to facilitate adult wasp activity and parasitism. The experimental data (Table 3) directly quantifies the increase in parasitism rate corresponding to different release densities, providing precise data support for developing specific regional control plans.

[0019] This invention utilizes natural enemy insects for biological control, fundamentally reducing the use of chemical pesticides and mitigating negative impacts on the environment and non-target organisms, thus meeting the requirements of green plant protection and ecological security. Through artificial propagation and release, it can actively establish and enhance natural enemy populations in pest outbreak areas, achieving sustained suppression of the fall webworm, and is particularly suitable for long-term control of the fall webworm and ecological restoration of epidemic areas. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the parasitic container.

[0022] Figure 2 This is a schematic diagram of the structure of a water container.

[0023] Explanation of reference numerals in the attached diagram: 1-can body, 2-lid, 3-mesh, 4-box body, 5-box lid, 6-cylindrical cotton swab. Detailed Implementation

[0024] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0025] Example 1: A method for controlling the fall webworm in the wild using the large-legged wasp.

[0026] I. Test Equipment Mating container: A 120-mesh single-door insect rearing cage with dimensions of 20 cm × 20 cm × 20 cm is used.

[0027] Parasite container: Use a cylindrical plastic container with a diameter of 8.5 cm and a height of 8.5 cm (e.g., Figure 1 The container includes a can body 1 and a lid 2. Several first round holes are made on the side wall of the can body 1 using a soldering iron. A second round hole is made in the center of the lid 2 using a soldering iron. A mesh 3 is attached to the outside of the first and second round holes.

[0028] Water container: Use a 40 mL capacity external snap-fit ​​integrated plastic box (such as...) Figure 2 The box includes a box body 4 and a box lid 5. The box lid 5 has a diameter of 4.8 cm, the box body 4 has a bottom diameter of 3.6 cm and a height of 3.8 cm. A third circular hole is made in the center of the box lid 5 using a soldering iron. A cylindrical cotton swab 6 is placed in the third circular hole. One end of the cylindrical cotton swab 6 is located on the outside of the box lid 5, and the other end passes through the third circular hole and abuts against the inside of the bottom of the box body 4.

[0029] II. Test Methods 1. Collect large-legged wasp species During the peak period of damage caused by the American white moth, American white moth pupae parasitized by the giant white wasp are collected from the wild and cultured indoors until the giant white wasp emerges as a seed source.

[0030] 2. Host rearing The fall webworm was reared in empty petri dishes. During the egg stage, absorbent cotton swabs were added to the petri dishes to maintain a humidity of 65±10%. When the egg pieces turned black, feed was added (the feed formula is the same as CN1994241A). When the feed was consumed or spoiled, new feed was added. The entire rearing process was completed in a clean bench until the fall webworm larvae pupated. After the pupae were collected, they were placed in a 5℃ incubator for later use.

[0031] 3. Parasitic propagation of the broad-legged wasp Using the American white moth pupa as a host, large-legged wasps were propagated. Breeding wasps that had just emerged 2±1 days prior were selected and kept in a mixed rearing cage with a female-to-male ratio of 1:3. A water container was placed in the rearing cage, and pure honey was applied to the mesh of the rearing cage. Mating took place for 7 days, during which time water (water was added to the box 4 and the lid 5 was closed, allowing the cylindrical cotton swabs 6 to absorb water and keep the wasps moist) and honey were provided.

[0032] To ensure the proportion of female wasps in the offspring, after the female wasps emerged and mated for 7 days, the lid 2 was opened, and the fully mated female wasps were sucked into container 1 using a wasp suction tube. One female wasp (20 days old) was placed in each container, and American white moth pupae were added for parasitism at wasp-pupa ratios of 1:10, 1:15, 1:20, 1:25, and 1:30 (mesh 3 was used for ventilation). The parasitism container was then placed in an artificial climate chamber with a photoperiod of 16 L:8 D, humidity of 60±5%, and light intensity of 4800 lx. The temperatures were set to 20℃, 25℃, and 30℃, respectively. After 24 hours of parasitism, the female wasps were removed, and the pupae were placed in plastic fruit fly tubes (24 mm in diameter and 95 mm in height), plugged with a sponge plug, and placed in an artificial climate chamber at 25℃ with the same photoperiod, humidity, and light intensity as described above until the large-legged wasps emerged. The number of emerged offspring was recorded, and the parasitism rate was calculated.

[0033] One, two, three, four, and five mated female wasps, each 20 days old, were placed in a plastic jar containing 125 American white moth pupae. The jars were then placed in an artificial climate chamber at 25°C, a photoperiod of 16L:8D, a humidity of 60±5%, and a light intensity of 4800 lx. After 24 hours, the female wasps were removed, and the pupae were placed in a petri dish and placed in the same climate chamber until the wasps emerged. The number of offspring was recorded, and the parasitism rate was calculated.

[0034] 4. Wild release of the large-legged wasp After five generations of reproduction, the *Hypertricis fasciatus* wasp was rejuvenated by collecting wild-collected wasps. Large, healthy wasps from indoor bee populations were mated with the wild-collected wasps at a ratio of 4:1. These were then used to parasitize the pupae of the fall webworm (*Triplophysa fulva*). Larger pupae were selected for parasitism, and after emergence, a rejuvenated *Hypertricis fasciatus* population was obtained. From this rejuvenated population, robust, mated adult wasps were selected for release into the wild. Two locations in Beijing, Fangshan Nanshangle Village and Tongzhou Yaoyi Park, where fall webworm infestation is severe, were chosen as release sites. Release densities were 50 wasps / acre, 100 wasps / acre, 150 wasps / acre, 200 wasps / acre, and 250 wasps / acre, respectively. Thirty days after release, 200 pupae were collected from each site to determine the parasitism rate. Release wasps were released at the early stage of the fall webworm pupal stage or in the early stages of infestation to ensure sufficient density of host pupae to support parasitism. Release time should be chosen on a clear, windless morning or evening, when the temperature (25±5℃) and humidity (60±5%) are suitable, avoiding periods of strong sunlight.

[0035] III. Test Results 1. Effects of different bee-pupa ratios and temperatures on the parasitism effect of the broad-legged wasp. As shown in Table 1, the parasitism effect is best when a single female bee faces 10 pupae; the parasitism rate decreases as the pupal density increases; and the overall parasitism effect is best when the temperature is set to 25℃. Therefore, a bee-to-pupa ratio of 1:10 is selected as the parasitism scheme.

[0036] Table 1. Parasitism effect of *Microsorum pupae* at different pupal ratios and temperatures. As shown in Table 2, the total number of parasites increases with increasing bee density, while the average number of parasites per bee decreases. This indicates that bee density has a certain interference effect on parasitism, and it is necessary to pay attention to controlling bee density.

[0037] Table 2 Total number of parasites and average number of parasites per bee under different female bee densities 2. The effect of releasing large-legged wasps in the wild on the parasitism of American white moth pupae. As shown in Table 3, the parasitism rate of American white moths increases with the increase of release density. At 250 moths / acre, the highest parasitism rate exceeds 50%, which is much higher than the natural parasitism rate of about 6.6% observed in the field.

[0038] Table 3. Parasitism of *Gastropoda spp.* at the release site. Although preferred embodiments of the invention have been described, those skilled in the art, once they have learned the basic inventive concept, can make other changes and modifications to these embodiments.

[0039] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for controlling the fall webworm in the field using the large-legged wasp, characterized in that, Includes the following steps: To cultivate a large number of legged wasps until they emerge as adults, thereby obtaining a source of wasp germs; Rearing fall webworms until larvae pupate, and collecting fall webworm pupae; Select mated female and male bees from the bee population source, parasitize the American white moth pupa, and raise the parasitized pupae until the offspring of the large-legged wasp emerge. After emergence, the large-legged wasp is propagated. After the large-legged wasp has been propagated for 4 to 6 generations, the indoor wasp species and the newly collected wild wasp species are mixed and mated at a ratio of 3 to 5:1, and then the American white moth pupa is used for parasitism to obtain a revitalized population. Select robust, mated adult wasps from the rejuvenated population as the release species and release them in areas severely affected by the fall webworm, at the early stage of the fall webworm pupal stage or the early stage of its occurrence.

2. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 1, characterized in that, The propagation is as follows: Female and male giant wasps with large legs that have emerged 1 to 3 days ago were placed in a mating container at a ratio of 1:2 to 4 for 7 days, and provided with water and honey. After mating, female wasps and American white moth pupae were placed in a parasitizing container at a ratio of 1:10~30. After the parasitism ends, the adult wasps are removed, and the parasitized pupae are cultured until the offspring of the large-legged wasps emerge.

3. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 2, characterized in that, The temperature at which the parasite resides is 20℃~30℃.

4. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 2, characterized in that, The light / dark ratio of the parasite is 14~18 / 6~10, and the light intensity is 4600 lx~5000 lx.

5. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 2, characterized in that, The humidity of the parasite is 55%~65%.

6. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 2, characterized in that, The parasitic duration is 22 h to 26 h.

7. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 2, characterized in that, The parasitic container includes a canister (1) and a lid (2). The canister (1) has several first round holes on its side wall and the lid (2) has a second round hole in the center. The first round holes and the second round holes are covered with mesh (3).

8. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 2, characterized in that, The water is replenished through a water container; the water container includes a box body (4) and a box cover (5), a third round hole is provided in the center of the box cover (5), a cylindrical cotton swab (6) is provided in the third round hole, one end of the cylindrical cotton swab (6) is located outside the box cover (5), and the other end passes through the third round hole and abuts against the bottom inner side of the box body (4).

9. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 1, characterized in that, The ambient temperature during the release of the bee species is 20℃~30℃, and the humidity is 55%~65%.

10. The method for controlling the fall webworm in the field using the large-legged wasp according to claim 1, characterized in that, The bee release density is 50 to 250 bees per acre.

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