Use of 1-octen-3-one in the control of plant nematode diseases

Abstract

This invention relates to the application of 1-octen-3-one in the control of plant nematodes, belonging to the field of plant pest and disease control. This invention uses different concentrations of 1-octen-3-one to kill or fumigate various nematodes, including Northern Root-Knot Nematode, Elephant Root-Knot Nematode, Grape Root-Knot Nematode, Luoding Sporangia Nematode, Pine Wood Nematode, and Whole Tooth Resurrection Nematode, all of which have strong toxic activity and can be used for the effective control of plant nematode diseases, providing a new agent for the control of plant nematode diseases.

Description

Technical Field

[0001] This invention belongs to the field of plant disease and pest control, specifically, it relates to the application of 1-octen-3-one in the control of plant nematode diseases. Background Technology

[0002] Plant nematodes are among the most important plant pathogens. With the industrialization and intensification of agriculture, and the long-term large-scale cultivation of monocultures, nematode diseases have become increasingly prominent. Root-knot nematodes (… Meloidogyne The plant species *S. spp.* have over 3,000 host plant species, including food crops, oil crops, fiber crops, tobacco, tea, fruits and vegetables, medicinal herbs, and flowers. Among them is the southern root-knot nematode (*S. spp.*). Meloidogyne incognita ), Northern root-knot nematodes ( M.hapla ), peanut root-knot nematode ( M.arenaria ) and Javan root-knot nematode ( M.javanica These are four common species, and it has been reported that over 90% of crop losses caused by root-knot nematodes are due to these four common species. In my country, the cereal cyst nematode (… Heterodera avenarea ), Philippine cyst nematode ( H.filipjevi ), soybean cyst nematode ( H. glycines ), rice cyst nematode ( H. elachista Rice cyst nematode ( H.oryzae ), rice cyst nematode ( H.oryzicola ) and sugarcane cyst nematode ( H.sacchari Cyst nematodes such as pine wilt nematode (Pinus thunbergii) are widespread and cause serious damage, resulting in losses and impacts on the production of wheat, soybeans, and rice in my country. Bursaphelenchus xylophilus Pine wilt disease is a devastating forest pathogen that has spread rapidly since it was first introduced to my country in 1982. It has caused serious damage to more than 70 species of conifers, including pine trees. The spread and damage caused by pine wilt disease have gradually intensified, seriously threatening the security of my country's forest resources and the balance of the ecological environment.

[0003] Currently, chemical control is an important and effective measure in the prevention and control of plant nematode diseases. However, there are relatively few common and highly effective nematicides, mainly abamectin, thiazophos, and fluopyram. Single or repeated use of the same nematicide can easily accelerate the development of pesticide resistance in plant pathogenic nematodes, leading to pesticide residues in crops and the environment. Therefore, the search for novel nematicides is one of the current and future research hotspots in the prevention and control of plant nematode diseases. Summary of the Invention

[0004] To address the problems existing in the background technology, the inventors of this invention conducted extensive experimental research. By analyzing the components of the bacterial fermentation broth that showed toxicity against root-knot nematodes obtained in previous studies, and using the detected components to conduct toxicity tests on various nematodes, it was finally determined that the component 1-octen-3-one in the bacterial fermentation broth has strong toxicity activity against various plant nematodes, providing a new agent for the prevention and control of plant nematode diseases.

[0005] To achieve the above objectives, the first objective of this invention is to provide the application of 1-octen-3-one in the control of plant nematode diseases.

[0006] Furthermore, the plant nematodes mentioned include root-knot nematodes, cyst nematodes, and pine wood nematodes.

[0007] Furthermore, the plant nematodes mentioned include the southern root-knot nematode. M. incognita Northern root-knot nematodes M.hapla Root-knot nematode M.enterolobii grape root-knot nematodes M. vitis Luoding cyst nematode Heterodera luodingensis pine wood nematode Bursaphelenchus xylophilus .

[0008] A second object of the present invention is to provide a medicament or drug comprising 1-octen-3-one for the control of plant nematode diseases.

[0009] The beneficial effects of this invention are:

[0010] Through experimental research, this invention has demonstrated that 1-octen-3-one has a strong toxic effect on plant nematodes, providing a new and effective agent for the prevention and control of plant nematode diseases.

[0011] The 1-octen-3-one of the present invention has a good toxic effect on southern root-knot nematodes, northern root-knot nematodes, weevils root-knot nematodes, grape root-knot nematodes, Luoding sporangia nematodes, and pine wood nematodes, with a high mortality rate. Attached Figure Description

[0012] Figure 1 The LC50 of different concentrations of 1-octen-3-one aqueous solutions against four root-knot nematodes is shown in Example 1 of this invention.

[0013] Figure 2 This is the LC50 of three root-knot nematodes fumigated with different concentrations of 1-octen-3-one in Example 3 of the present invention;

[0014] Figure 3 This is the LC50 of different concentrations of 1-octen-3-one fumigated with Roding cyst nematodes in Example 4 of the present invention;

[0015] Figure 4This is the LC50 of different concentrations of 1-octen-3-one fumigation of *Nematodeus buergerianus* and *Nematodeus pineus* in Example 5 of this invention;

[0016] Figure 5 This is the toxic effect of 1-octen-3-one aqueous solution on root-knot nematodes of the bean plant in Example 1 of the present invention. Figure A: J2 survives in a bent or twisted state after being treated with sterile water; Figure B shows J2 in a rigid and dead state after being treated with 1-octen-3-one aqueous solution. Detailed Implementation

[0017] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0018] To illustrate the present invention more clearly, the following embodiments will be described in detail.

[0019] Example 1: Determination of the contact toxicity of 1-octen-3-one against various root-knot nematodes

[0020] 1. Materials

[0021] 1-Octen-3-one (95%) (Shanghai Yi'en Chemical Technology Co., Ltd.) was purchased from the market. Southern root-knot nematode, northern root-knot nematode, bean root-knot nematode, and grape root-knot nematode were all propagated using the cucumber variety Jin Yan No. 4.

[0022] 2. Methods

[0023] 2.1 Solution Preparation

[0024] Mix 2 μL of 1-octen-3-one with 50 mL of water to prepare a stock solution with a concentration of 40 μL / L. Dilute the stock solution to the corresponding concentration before use.

[0025] 2.2 Preparation of suspension of second instar larvae (J2) of root-knot nematodes:

[0026] The roots of cucumbers infected with Northern Root-knot Nematode, Southern Root-knot Nematode, Elephant Root-knot Nematode, and Grape Root-knot Nematode were rinsed clean. Egg masses of the four types of root-knot nematodes were collected and placed on a cell sieve with a pore size of 40 μm. The nematodes were then placed in a 6 cm culture dish and incubated in the dark at 26°C for 3-5 days. J2 was collected and a root-knot nematode J2 suspension with a concentration of 150 nematodes / 500 μL was prepared for later use.

[0027] 2.3 Bioassay of Northern Root-Knot Nematodes, Southern Root-Knot Nematodes, Bean Root-Knot Nematodes, and Grape Root-Knot Nematodes (using the immersion method):

[0028] Using 12-well plates, 500 μL of nematode suspension was added to each well. For each nematode species, 500 μL of 1-octen-3-one solution at concentrations of 4 μL / L, 8 μL / L, 12 μL / L, 16 μL / L, 20 μL / L, and 24 μL / L were added, and 1-octen-3-one solutions at final concentrations of 2 μL / L, 4 μL / L, 6 μL / L, 8 μL / L, 10 μL / L, and 12 μL / L were used for toxicity testing. Each treatment was repeated 6 times, with sterile water as a control. The plates were incubated at 26°C. The total number of tested nematodes and the number of deaths were observed and counted at 12 h, 24 h, and 36 h, and the mortality rate and corrected mortality rate were calculated.

[0029] Methods for determining nematode mortality and calculating mortality rate (the same applies to the following examples):

[0030] Determining nematode mortality: Add 10 μL of 1 mol / L sodium hydroxide to each well for stimulation. Nematodes that remain stiff and immobile after stimulation are considered dead.

[0031] Nematode mortality rate (%) = (Number of dead nematodes / Number of tested nematodes) × 100%

[0032] Corrected mortality rate (%) = (Nematode mortality rate in treatment group - Nematode mortality rate in control group) / (1 - Nematode mortality rate in control group) × 100%

[0033] The lethal median concentration (LC50) was calculated using the software Graphpad Prism 10.0 for curve fitting.

[0034] Contact toxicity results of 1-octen-3-one aqueous solution (Table 1 and Figure 1 The results showed that 1-octen-3-one exhibited strong toxic activity against *Ixodes spp.*, *Ixodes spp.*, *Ixodes spp.*, *Ixodes spp.*, and *Ixodes spp.*. The corrected mortality rates of the four root-knot nematodes J2 after 12 h treatment with 8 μL / L 1-octen-3-one solution ranged from 85.38% to 98.14%. The LC50 values ​​of 1-octen-3-one solution for *Ixodes spp.*, *Ixodes spp.*, *Ixodes spp.*, and *Ixodes spp.* after 12 h were 4.898 μL / L, 5.316 μL / L, 5.423 μL / L, and 5.790 μL / L, respectively.

[0035] Table 1. Corrected mortality rate (%) of four root-knot nematodes after 12 h of treatment with different concentrations of 1-octen-3-one aqueous solution.

[0036]

[0037] Example 2: Determination of the contact toxicity of 1-octen-3-one against *Resurrection nematode*

[0038] The whole-toothed resurrected nematodes were cultured on oat medium, and the whole-toothed resurrected nematodes (mixed instars) were collected by rinsing with sterile water and prepared into a suspension of 150 nematodes / 500 μL for later use.

[0039] Using 12-well plates, 500 μL of *C. truncatula* suspension and 500 μL of 1-octen-3-one aqueous solution of different concentrations were added to each well. The final working concentrations of 1-octen-3-one were 4, 6, 8, 10, and 20 μL / L. Sterile water was used as a control. Each treatment was repeated 6 times. The plates were placed in a 26°C incubator. The total number of tested nematodes and the number of deaths were observed and counted at 12 h, 24 h, and 36 h. The mortality rate and corrected mortality rate were calculated.

[0040] The methods for determining mortality and calculating mortality rate are the same as in Example 1. The software Graphpad Prism 10.0 is used for curve fitting and calculation of the lethal concentration LC50.

[0041] The results showed that the corrected mortality rate of *Resurrection nematodes* treated with 20 μL / L 1-octen-3-one was 39.26% at 12 h, 45.6% at 24 h, and 45.88% at 36 h. The LC50 was 27.33 μL / L at 12 h, 23.02 μL / L at 24 h, and 22.72 μL / L at 36 h.

[0042] Table 2. Corrected mortality rate (%) of *Resurrection nematode* at three time periods after treatment with different concentrations of 1-octen-3-one aqueous solution.

[0043]

[0044] Example 3: Determination of the fumigation toxicity of 1-octen-3-one against three root-knot nematodes

[0045] Grape root-knot nematode J2, northern root-knot nematode J2, and elephant ear bean root-knot nematode J2 were obtained using the same method as in Example 1 and prepared into a suspension of 150 nematodes / 500 μL for later use.

[0046] Using 24-well plates, 500 μL of J2 suspension was added to each well. The 24-well plates were placed in a 3.5 L sealed container. 1-Octen-3-one was added to the container to form volatiles of 10, 5, 2.5, 1.25, 0.625, and 0.3125 ppb (ppb: parts per billion, i.e., 0.001 μL / L), respectively. A control without 1-octen-3-one was used. Each treatment was replicated six times. The plates were incubated at 26°C in the dark for 24 h. The total number of nematodes and the number of deaths were observed and counted. The mortality rate and corrected mortality rate were calculated. Graphpad Prism 10.0 software was used for curve fitting and calculation of the median lethal concentration (LC50).

[0047] result( Figure 2 The results showed that when grape root-knot nematode J2, northern root-knot nematode J2, and elephant ear bean root-knot nematode J2 were treated with 0.1 μL / L 1-octen-3-one in the air for 24 h, the corrected mortality rate of all three root-knot nematode J2 species was 100%. The LC50 values ​​of 1-octen-3-one fumigation treatment for elephant ear bean root-knot nematode J2, northern root-knot nematode J2, and grape root-knot nematode J2 for 24 h were 2.47 ppb (0.00247 μL / L), 5.454 ppb (0.005454 μL / L), and 14.25 ppb (0.01425 μL / L), respectively.

[0048] Example 4: Determination of the fumigation toxicity of 1-octen-3-one against *Cytozoon rodingensis*

[0049] Isolation of sporangia from diseased soil: Pour the diseased soil into a 1 L plastic beaker, add 1 L of water, stir with a glass rod until the soil is suspended, let stand for 30-40 s, pass the supernatant through 20 and 80 mesh sieves, repeat the above operation three times, rinse the sieve with water, collect the material on the 80 mesh sieve into a funnel lined with qualitative filter paper for filtration, pick up the sporangia on the filter paper with a dissecting microscope, and store in a refrigerator at 4℃.

[0050] Hatching of cyst nematodes: Place the eggs of cyst nematodes into a 40 μm cell sieve, place the cell sieve in a 6 cm culture dish, add sterile water, and incubate at 26℃ for 5-7 days. When a large number of cyst nematodes J2 have hatched, collect them for later use.

[0051] Cyst nematodes J2 were prepared as a suspension of 150 nematodes per 500 μL for later use.

[0052] Using 24-well plates, 500 μL of J2 suspension was added to each well. The 24-well plates were placed in a 3.5 L sealed container. 1-Octen-3-one was added to the sealed container to form volatiles of 100, 10, 1, 0.1, and 0.01 ppb (ppb: parts per billion, i.e., 0.001 μL / L), respectively. A control without 1-octen-3-one was used. Each treatment was repeated 6 times. The plates were incubated at 26°C in the dark for 12 h. The total number of nematodes and the number of deaths were observed and counted. The mortality rate and corrected mortality rate were calculated. Graphpad Prism 10.0 software was used for curve fitting and calculation of the median lethal concentration (LC50).

[0053] result( Figure 3 The results showed that when the concentration of 1-octen-3-one in the air was 100 ppb (0.1 μL / L), the corrected mortality rate of *Cytozoa rodingensis* J212 h was 100%, and the LC50 of 1-octen-3-one fumigation treatment of *Cytozoa rodingensis* J212 h was 10 ppb (0.01 μL / L).

[0054] Example 5: Determination of the fumigation toxicity of 1-octen-3-one against *Pinus fibrosum* and *Resurrection thymosinus*.

[0055] Use Botrytis cinerea ( Botrytis Pine wood nematodes were cultured on oat medium, and *Nematoda* sp. were cultured on oat medium. Pine wood nematodes (mixed instars) and *Nematoda* sp. (mixed instars) were collected by rinsing with sterile water and prepared into suspensions of 150 nematodes / 500 μL. Using 24-well plates, 500 μL of nematode suspension was added to each well. The 24-well plates were placed in a 1 L sealed container. 20 μL, 10 μL, 1 μL, 0.1 μL, and 0.01 μL of 1-octen-3-one were added to the sealed container to create volatiles at concentrations of 20 μL / L, 10 μL / L, 1 μL / L, 0.1 μL / L, and 0.01 μL / L, respectively. A control without 1-octen-3-one was used. Each treatment was replicated six times. The plates were incubated at 26°C in the dark for 24 h. The total number of tested nematodes and the number of dead nematodes were observed and counted, and the mortality rate and corrected mortality rate were calculated. The lethal median concentration (LC50) was calculated using the software Graphpad Prism 10.0 for curve fitting.

[0056] Results (Table 3 and Figure 4The results showed that fumigating *Pinus wiltii* with 1-octen-3-one at a concentration of 10 μL / L for 24 h resulted in a corrected mortality rate of 100%, as did fumigating *Resurrection thyrsiflora* with 1 μL / L for 24 h. The LC50 of 1-octen-3-one fumigation for 24 h was 0.053 μL / L, and the LC50 of 1-octen-3-one fumigation for 24 h was 1.71 μL / L.

[0057] Table 3. Corrected mortality rate (%) of pine wood nematode and *Resurrection thymosus* after 24 h of fumigation with different concentrations of 1-octen-3-one.

[0058]

[0059] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. Application of 1-octen-3-one in the control of plant nematode diseases.

2. The application according to claim 1, characterized in that, The plant nematodes mentioned include root-knot nematodes, cyst nematodes, and pine wood nematodes.

3. The application according to claim 1, characterized in that, The plant nematodes mentioned include the southern root-knot nematode ( M. incognita) Northern root-knot nematodes ( M. hapla) , Bean root nematode ( M. enterolobii) Grape root-knot nematodes ( M. vitis) Luoding cyst nematode ( Heterodera luodingensis) Pine wood nematode ( Bursaphelenchus xylophilus) .

4. A pesticide for controlling plant nematode diseases, characterized in that, It contains 1-octen-3-one.

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