A method for biological control of scirtothrips dorsalis

Abstract

The application discloses a kind of biological control method of tea stick thrips, belong to the technical field of agricultural pest control.The method includes the step that the solution containing insect pathogenic nematode is sprayed to the soil in tea garden to carry out biological control to tea stick thrips;Wherein, the insect pathogenic nematode includes at least one of Steinernema feltiae SN or S.carpocapsae All.The application selects two kinds of insect pathogenic nematodes with high virulence effect on tea stick thrips from four common EPNs, and the biological control of tea stick thrips is carried out using the two kinds of insect pathogenic nematodes, which can achieve more than 75% control effect, effectively control tea stick thrips, reduce the harm of tea stick thrips to tea, significantly improve the yield and quality of tea, and reduce the chemical pesticide residues of tea.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural pest control, in particular to a biological control method for tea thrips. Background Art

[0002] Tea thrips, also known as "tea thrips" and "Miller's thrips," belong to the genus Dendrothrips, family Thripidae, order Thysanoptera. They are one of the most prominent pests in tea production. Their small size, their habit of hiding between buds and branches, their large egg-laying capacity, and their rapid reproduction and generational turnover make them challenging to control. Their primary detriment is feeding on young tea buds with their rasp-sucking mouthparts, leaving visible rasp marks on the leaves, impacting their growth and production. They also pose a potential risk of spreading diseases, severely impacting tea yield and quality. In some areas, this can severely impact the summer and autumn tea harvests, resulting in significant economic losses to tea plantations annually. The control of tea thrips primarily relies on chemical pesticides such as spinetoram, spinosad, and cypermethrin. However, the long-term and extensive use of these pesticides has led to resistance in tea leaves. Furthermore, their long-term and extensive use has resulted in excessive pesticide residues in tea leaves, potentially harming human health and the ecological environment. As countries tighten their regulations on chemical pesticide residues, the use of chemical pesticides in tea leaves is increasingly restricted.

[0003] EPNs (Entomopathogenic Nematodes) are a new type of biopesticide. Compared to other biopesticides, these nematodes have a wide range of hosts; they actively search for hosts, particularly soil-dwelling and borer pests; and they are biosafe for humans, animals, and plants. Previous investigations have revealed that tea thrips complete their life cycle by burrowing into the soil to pupate, making it possible to use EPNs for biological control of thrips. Screening for EPNs with effective control of tea thrips is of great significance for biological control of tea thrips. Summary of the Invention

[0004] The present invention aims to provide a biological control method for tea thrips to address the problems of the prior art. The present invention screens two entomopathogenic nematodes with high toxicity to tea thrips. Using these two entomopathogenic nematodes for biological control of tea thrips can achieve a control efficiency of over 75%, effectively controlling tea thrips.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a biological control method for tea thrips, comprising the steps of spraying a solution containing entomopathogenic nematodes into tea garden soil to biologically control the tea thrips;

[0007] Wherein, the entomopathogenic nematodes include at least one of Steinernemafeltiae SN or S.carpocapsaeAll.

[0008] Furthermore, in the solution containing entomopathogenic nematodes, the concentration of the entomopathogenic nematodes is 1000 IJs / mL.

[0009] Furthermore, the usage of the entomopathogenic nematodes is calculated based on the number of entomopathogenic nematodes and the number of tea thrips, with a ratio of 100:1.

[0010] Furthermore, the solution containing entomopathogenic nematodes is obtained by dissolving the entomopathogenic nematode powder in water and diluting it.

[0011] Furthermore, when the dilution exceeds 6 hours, the dilution solution should be refrigerated and the refrigerated storage temperature is 4-10°C.

[0012] Furthermore, the tea thrips are third-instar nymphs of tea thrips.

[0013] The present invention also provides an application of an entomopathogenic nematode in biological control of tea thrips, wherein the entomopathogenic nematode comprises at least one of Steinernemafeltiae SN or S.carpocapsaeAll.

[0014] Furthermore, the entomopathogenic nematode is S. carpocapsae All.

[0015] Furthermore, the tea thrips are third-instar nymphs of tea thrips.

[0016] The present invention discloses the following technical effects:

[0017] The present invention screens out two entomopathogenic nematodes with high toxicity to tea thrips from four common EPNs, namely Steinernema feltiae SN and S. carpocapsae All. Utilizing these two entomopathogenic nematodes for biological control of tea thrips can achieve a control effect of more than 75%, effectively controlling tea thrips, reducing the damage caused by tea thrips to tea, significantly improving the yield and quality of tea, and reducing chemical pesticide residues in tea. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 The control effect of four entomopathogenic nematodes on tea thrips for 144 hours;

[0020] Figure 2 The control effect of different concentrations of highly virulent entomopathogenic nematodes on tea thrips;

[0021] Figure 3 This is a pot experiment on the control effect of highly virulent entomopathogenic nematodes on tea thrips;

[0022] Figure 4 This is a field experiment on the control effect of highly virulent entomopathogenic nematodes on tea thrips. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0026] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0027] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0028] The four common EPNs used in the examples of the present invention are Steinernemafeltiae SN; S. longicaudum X-7; S. carpocapsae All and Heterorhabditis bacteriophora H06, all of which are provided by Weifang Hongrun Agricultural Technology Co., Ltd.

[0029] Example 1 Screening of highly toxic EPNs strains of Thrips spp.

[0030] Four common EPNs were selected, namely Steinernemafeltiae SN (SF); S. longicaudum X-7 (X-7); S. carpocapsae All (SC) and Heterorhabditis bacteriophora H06 (H06).

[0031] 1. Screening of highly toxic EPNs strains

[0032] Two layers of circular filter paper were placed at the bottom of each culture dish. 0.5 mL of each of the four EPNs at a concentration of 1000 IJs / mL was inoculated into each culture dish, and 0.5 mL of distilled water was added as a control. Ten third-instar larvae of tea thrips were placed in each culture dish, and tender and fresh tea leaves were added as a food source for the larvae. All culture dishes were cultured at 24 ± 1 ° C, and the larval mortality rate was recorded every day for 6 days. Each nematode treatment was repeated 6 times. The strains with a mortality rate of not less than 50% were selected as highly toxic EPNs for the next experiment ( Figure 1 ).

[0033] Depend on Figure 1 It can be seen that after 6 days of culture (144h), the corrected mortality of the third-instar nymphs of tea thrips in the culture dishes inoculated with the nematodes Steinernemafeltiae SN and S.carpocapsaeAll reached more than 75%. Therefore, the nematodes Steinernemafeltiae SN and S.carpocapsaeAll were selected as the highly toxic EPNs strains of tea thrips.

[0034] 2. Screening of concentrations of highly toxic EPNs for controlling tea thrips

[0035] The screened highly toxic EPNs Steinernemafeltiae SN and S.carpocapsaeAll were diluted with water to prepare 30, 60, 120, 240, 480, 600 and 1000 IJs / mL dilutions, respectively. The dilutions were inoculated into culture dishes within 4-6 hours (method as in 1.). If more than 6 hours have passed, the dilutions must be refrigerated at 4-10°C, otherwise the control effect will be affected. 10 third-instar larvae of tea thrips were placed in each culture dish, and then tender and fresh tea leaves were added as a food source for the larvae. All culture dishes were cultured at 24±1°C, and the larval mortality was checked every day for 6 days. Each treatment was repeated 6 times. Two days after death, all dead thrips were dissected under a 40x stereomicroscope. Only insects showing nematodes in their bodies were considered to have been killed by EPN ( Figure 2 ).

[0036] Depend on Figure 2 It can be seen that different concentrations of EPNs have different control effects on tea thrips. When the EPNs concentration reaches 1000IJs / mL, the control effect is the best.

[0037] Example 2 Potted experiment on the control of tea thrips by highly toxic EPNs

[0038] On the basis of Example 1, high toxicity and optimal concentration (1000IJs / mL) EPNs were used in pot experiments. 50 3rd instar nymphs and 50 adults were released in the fresh tea leaves of each tea seedling plant. Three days after the larvae were introduced into the tea seedlings, the soil of the potted tea seedlings was sprayed with the screened high toxicity and optimal concentration EPNs, with water as a negative control and ethyl spinetoram as a positive control. The pots were organized in a completely randomized design, with 5 replicate pots for each treatment. Ten days after the application of EPN, samples were taken to record the number of adults appearing in the treated and untreated control plants ( Figure 3 ).

[0039] like Figure 3 As shown in the figure, the pot experiment proved that highly toxic EPNs had a good control effect on tea thrips.

[0040] Example 3 Investigation of Field Population Dynamics of Thrips Using Highly Toxicity EPNs

[0041] Field experiments were conducted in natural tea gardens severely infested with tea thrips. Each tea garden had 15 experimental plots, covering an area of ​​20 m2. 2(4m×5m). The experimental design was a randomized design, including 5 treatments: highly toxic EPNs (S.carpocapsaeAll), highly toxic EPNs (S.carpocapsaeAll) + tiny flower bugs, tiny flower bugs, ethyl spinetoram, and water control, with 3 replicates for each treatment. Before the experiment, a five-point sampling method was used to randomly survey 20 branches at each point. The number of tea thrips on one bud and two leaves was surveyed on each branch. The amount of highly toxic EPNs used was estimated based on the number of surveys before the experiment. The ratio of the number of entomopathogenic nematodes to the number of tea thrips was 100:1. After use, the survey was conducted every 10 days (until the garden was closed in winter). During this period, EPNs, tiny flower bugs, and pesticides were added to each treatment according to the damage of thrips.

[0042] Figure 4 As shown in the figure, field experiments have demonstrated the control effect of highly toxic EPNs on tea thrips, and highly toxic EPNs also have a good control effect on tea thrips.

[0043] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A biological control method for tea stick thrips, characterized in that: The method comprises the steps of spraying a solution containing entomopathogenic nematodes into tea garden soil to carry out biological control of tea thrips; Wherein, the entomopathogenic nematode comprises at least one of Steinernema feltiae SN or S .carpocapsae All; In the solution containing entomopathogenic nematodes, the concentration of the entomopathogenic nematodes is 1000 IJs / mL.

2. The biological control method according to claim 1, characterized in that: The usage of the entomopathogenic nematodes is calculated based on the number of entomopathogenic nematodes and the number of tea thrips, and the ratio is 100:

1.

3. The biological control method according to claim 1, characterized in that: The solution containing entomopathogenic nematodes is obtained by dissolving the entomopathogenic nematode powder in water and diluting it.

4. The biological control method according to claim 1, characterized in that: The tea thrips are third-instar nymphs of the tea thrips.

5. An application of an entomopathogenic nematode in biological control of tea thrips, characterized in that: The entomopathogenic nematodes include at least one of Steinernema feltiae SN or S. carpocapsae All.

6. The use according to claim 5, characterized in that The entomopathogenic nematode is S. carpocapsae All.

7. The use according to claim 5, characterized in that The tea thrips are third-instar nymphs of the tea thrips.

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