Method for artificially breeding egg parasitic wasps of empoasca fabae by using eggs of nilaparvata lugens and application thereof

Abstract

The application discloses a method for artificially breeding egg parasitic wasps of Eriosoma larigerum by using eggs of Nilaparvata lugens and application, and relates to the technical field of biological control of agricultural pests. The application utilizes the advantages that the eggs of the Nilaparvata lugens are similar to the eggs of the Eriosoma larigerum in size and development, and the eggs of the Nilaparvata lugens are easier to be mass-produced, and realizes that the egg parasitic wasps of the Eriosoma larigerum can actively parasitize the eggs of the Nilaparvata lugens through step-by-step domestication, and the offspring of the egg parasitic wasps can complete development and eclosion into adults in the eggs of the Nilaparvata lugens, so that the artificial mass feeding of the egg parasitic wasps of the Eriosoma larigerum is possible.

Description

Technical Field

[0001] This invention relates to the field of biological control technology for agricultural pests, specifically to a method and application of artificially raising tea green leafhopper egg parasitic wasps using brown planthopper eggs. Background Technology

[0002] In rice and tea cultivation, pests are a major factor affecting yields. Among these pests, two types of hemiptera pests, the rice planthopper (Delphacidae, which damages rice) and the tea green leafhopper (Cicadellidae, which damages tea), are particularly serious. These two pests cause damage in similar ways: 1) Adults and nymphs suck sap from the phloem, consuming plant nutrients; 2) Female adults lay eggs within tissues, hindering the transport of water and nutrients; 3) Tissue damage caused by piercing and oviposition facilitates pathogen infection; 4) Honeydew secreted by these pests attracts mold growth and affects photosynthesis and respiration. After damage from these two pests, the tops of the plants (rice and tea) wither and die, appearing scorched, known as hopper burn, which can lead to complete crop failure in severe cases. The dominant species of tea green leafhopper in my country is Empoasca onukii, which is a major pest in the four major tea-producing areas of South China, Southwest China, Jiangnan and Jiangbei.

[0003] Egg parasitic wasps use their unique needle-like ovipositor to pierce the host egg and lay their eggs. The eggs hatch inside the host egg, and the wasps obtain nutrients by feeding on the tissues inside the host egg, growing and developing until the adult emerges, leaving only an empty shell of the host egg. Because the tea green leafhopper prefers to lay its eggs in the tender shoots or leaves of tea plants, and mostly lays them singly, it is difficult to find and obtain large quantities of tea green leafhopper eggs under artificial conditions, thus limiting the artificial rearing of its egg parasitic wasps. Summary of the Invention

[0004] The inventors discovered that female brown planthoppers use their needle-like ovipositors to create a slit in the epidermis of rice plant stems, then lay their eggs one by one, embedding them into the rice tissue to form egg masses. Each egg mass contains several to a dozen eggs, leaving oviposition marks on the stem surface, making them easily noticeable. Furthermore, brown planthopper eggs have already been successfully reared and collected in large quantities artificially. Therefore, using brown planthopper eggs as an alternative host holds promise for the artificial rearing of tea green leafhopper egg parasitoid wasps, thus providing a stable source of insects for basic research and applications of tea green leafhopper egg parasitoid wasps.

[0005] Therefore, this invention provides an indoor artificial rearing method for tea green leafhopper egg parasitoid wasps using brown planthopper eggs and its application. This method utilizes brown planthopper eggs to achieve host conversion of tea green leafhopper egg parasitoid wasps that use tea green leafhopper eggs as the host, and can obtain stable indoor strains of tea green leafhopper egg parasitoid wasps that parasitize brown planthopper eggs, thus realizing the artificial rearing of tea green leafhopper egg parasitoid wasps.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] According to a first aspect of the present invention, the present invention provides a method for artificially raising tea green leafhopper egg parasitic wasps indoors, the method comprising the following steps:

[0008] (1) Select a tender tea shoot with one bud and four leaves containing tea green leafhopper eggs laid within 48 hours. Insert brown planthopper eggs laid within 48 hours next to the tea green leafhopper eggs and live with female adult tea green leafhopper egg parasitoids within 12 hours of emergence. After 24-48 hours, remove the brown planthopper eggs, cultivate them, and collect the female adult tea green leafhopper egg parasitoids that have emerged.

[0009] (2) Select another one-bud four-leaf tea shoot containing brown planthopper eggs laid within 48 hours, and place it together with the female adult tea green leafhopper egg parasitoid wasp collected in step (1). After 24-48 hours, remove the brown planthopper eggs, cultivate them, and collect the female adult tea green leafhopper egg parasitoid wasp that have emerged.

[0010] (3) Select rice stems containing brown planthopper egg masses within 48 hours of egg laying and place them together with the female adult tea green leafhopper egg parasitoid wasps collected in step (2). After 48 hours, collect the brown planthopper eggs, select the brown planthopper eggs that have been parasitized, cultivate them, and collect the female adult tea green leafhopper egg parasitoid wasps that have emerged.

[0011] Furthermore, the method also includes:

[0012] (4) Repeat step (3) 1-10 times until stable offspring of the tea green leafhopper egg parasitoid wasp that can actively search for and parasitize brown planthopper eggs in rice stems are obtained. This stable offspring are then placed in rice seedlings containing brown planthopper eggs for continued breeding, thus establishing a tea green leafhopper egg parasitoid wasp strain bred from brown planthopper eggs.

[0013] Further, in step (1), the parasitic wasps of the tea green leafhopper egg are species of the genus Mymaridae, including Stethynium empoascae, Schizophragma parvulas, and Arescon sp.

[0014] Furthermore, the cultivation conditions are as follows: brown planthopper eggs are placed in a petri dish lined with moist sterile filter paper, and the petri dish is covered with a lid and the gaps are sealed with paraffin film to prevent moisture loss and microbial infection.

[0015] According to a second aspect of the present invention, the present invention provides the application of the method for indoor artificial rearing of tea green leafhopper egg parasitic wasps as described in any of the preceding claims in rice and tea cultivation.

[0016] The embodiments of the present invention have the following advantages:

[0017] This invention utilizes the similarity in size and development between brown planthopper eggs and tea green leafhopper eggs, as well as the advantage that brown planthopper eggs are easier to mass-produce. Through step-by-step domestication, the tea green leafhopper egg parasitoid wasp can actively parasitize brown planthopper eggs, and its offspring can complete their development and emerge as adults inside the brown planthopper eggs, providing a possibility for the artificial mass breeding of tea green leafhopper egg parasitoid wasps. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in 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 merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 A comparison image of brown planthopper eggs (left) and tea green leafhopper eggs (right) provided by the present invention;

[0020] Figure 2 The images provided by this invention show the parasitic infestation of brown planthopper eggs by the tea green leafhopper egg parasitizer wasp. The left image shows the brown planthopper eggs parasitized by the tea green leafhopper egg parasitizer wasp, and the right image shows the brown planthopper eggs parasitized by the rice leafhopper wasp (brown planthopper egg parasitizer wasp). Detailed Implementation

[0021] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0022] Example 1

[0023] During the occurrence of the tea green leafhopper, in tea gardens where no pesticides were sprayed, tender tea shoots with one bud and four leaves were collected based on the leafhopper's tendency to lay eggs near tender shoots. These shoots were then brought indoors, and under a microscope, leafhopper egg-laying marks were located on the shoots. Based on these marks, the leafhopper eggs embedded within the shoots were positioned. The surrounding tea shoot tissue was gently separated to determine the developmental stage of the eggs. Leaves laid within 48 hours were selected (before the red eyespots appeared). The eggs, along with the tea shoot, were cut off and placed in a petri dish with moist, sterile filter paper. The eggs were not separated from the tea shoot but placed close to the leafhopper eggs, mimicking the appearance of the tea shoot. The embedding method for the tea green leafhopper involves carefully placing 1-2 brown planthopper eggs (within 48 hours of egg-laying) and then introducing 2-5 adult female tea green leafhopper egg parasitizers (within 12 hours of emerging from the tea green leafhopper eggs). These are allowed to find and parasitize host eggs. Because brown planthopper eggs are similar in shape, color, and size to tea green leafhopper eggs, and because they are embedded in tender tea shoots and close to the eggs, the tea green leafhopper egg parasitizers can easily confuse the nearby brown planthopper eggs with the tea green leafhopper eggs after locating them using their antennae to receive olfactory information. (The parasitism success rate of brown planthoppers by tea green leafhopper egg parasitizers can be over 20%). After 24 hours, the brown planthopper eggs are removed and cultured separately. The brown planthopper eggs are placed in a petri dish lined with moist, sterile filter paper. The petri dish is then covered and sealed with paraffin wax to prevent moisture loss and microbial infection. After the brown planthopper eggs are parasitized, the offspring of the tea green leafhopper egg parasitoid wasps inside the eggs can develop normally and complete the development of each instar by feeding on the brown planthopper egg tissue. Finally, they emerge as adults from the brown planthopper eggs.

[0024] Collect female adult tea green leafhopper egg parasitoids that have emerged from brown planthopper eggs. Prepare brown planthopper eggs laid within 12 hours of hatching and carefully embed them into the tissue of a fresh one-bud, four-leaf tea shoot. Introduce the collected female adult tea green leafhopper egg parasitoids into the tea shoot containing brown planthopper eggs, allowing them to find and parasitize host eggs. After 48 hours, remove the brown planthopper eggs to observe for internal parasitism. Cultivate the parasitized brown planthoppers separately until the offspring of the parasitoids within the brown planthopper eggs emerge as adults, then collect the female adults for later use.

[0025] Brown planthopper eggs that have been laid inside rice stems for no more than 12 hours were prepared. The brown planthopper eggs were kept in contact with the collected female adult tea green leafhopper egg parasitoid wasps for 48 hours without being separated from the rice stems. The brown planthopper eggs were then collected, and the parasitism was observed and recorded. The parasitized brown planthopper eggs were further cultivated, and the female adult tea green leafhopper egg parasitoid wasps that emerged were collected. Repeat this step until the tea green leafhopper egg parasitoid wasp can stably parasitize brown planthopper eggs inside rice stems. Specifically, single-headed female tea green leafhopper egg parasitoid wasps can actively search for and parasitize brown planthopper eggs, with a parasitism count of ≥5 within 24 hours. They can develop normally inside the brown planthopper eggs, emerge as adults, and the success rate of emergence of offspring is ≥70%. The body length of the offspring adults is not statistically significantly different from that of the same species of tea green leafhopper egg parasitoid wasp parasitizing tea green leafhopper eggs. Thus, an indoor strain of tea green leafhopper egg parasitoid wasp with brown planthopper eggs as the host has been successfully established.

[0026] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for indoor artificial rearing of parasitic wasps for tea green leafhopper eggs, characterized in that, The method includes the following steps: (1) Select a tender tea shoot with one bud and four leaves containing tea green leafhopper eggs laid within 48 hours. Insert brown planthopper eggs laid within 48 hours next to the tea green leafhopper eggs and live with female adult tea green leafhopper egg parasitoids within 12 hours of emergence. After 24-48 hours, remove the brown planthopper eggs, cultivate them, and collect the female adult tea green leafhopper egg parasitoids that have emerged. (2) Select another one-bud four-leaf tea shoot containing brown planthopper eggs laid within 48 hours, and place it together with the female adult tea green leafhopper egg parasitoid wasp collected in step (1). After 24-48 hours, remove the brown planthopper eggs, cultivate them, and collect the female adult tea green leafhopper egg parasitoid wasp that have emerged. (3) Select rice stems containing brown planthopper egg masses within 48 hours of egg laying and place them together with the female adult tea green leafhopper egg parasitoid wasps collected in step (2). After 48 hours, collect the brown planthopper eggs, select the brown planthopper eggs that have been parasitized, cultivate them, and collect the female adult tea green leafhopper egg parasitoid wasps that have emerged.

2. The method for indoor artificial rearing of tea green leafhopper egg parasitic wasps according to claim 1, characterized in that, The method further includes: (4) Repeat step (3) 1-10 times until stable offspring of the tea green leafhopper egg parasitoid wasp that can actively search for and parasitize brown planthopper eggs in rice stems are obtained. This stable offspring are then placed in rice seedlings containing brown planthopper eggs for continued breeding, thus establishing a tea green leafhopper egg parasitoid wasp strain bred from brown planthopper eggs.

3. The method for indoor artificial rearing of tea green leafhopper egg parasitic wasps according to claim 1, characterized in that, In step (1), the parasitic wasps of the tea green leafhopper egg are species of the genus Mymaridae, including Stethynium empoascae, Schizophragma parvulas, and Aresconsp.

4. The method for indoor artificial rearing of tea green leafhopper egg parasitic wasps according to claim 1, characterized in that, The cultivation conditions are as follows: brown planthopper eggs are placed in a petri dish lined with moist sterile filter paper, and the petri dish is covered with a lid and the gaps are sealed with paraffin film to prevent moisture loss and microbial infection.

5. The method of indoor artificial rearing of tea green leafhopper egg parasitic wasps according to any one of claims 1-4, applied to rice and tea cultivation.

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