Use of dimethyl trisulfide

Abstract

The application belongs to the technical field of agricultural pest control, and discloses an application of dimethyl trisulfide. The dimethyl trisulfide is applied to a nematicide, and through the determination of the mortality of Bursaphelenchus xylophilus, Meloidogyne incognita and Pratylenchus penetrans, it is found that fumigation and immersion have good killing effects on the three kinds of nematodes. For fumigation, the median lethal concentration of Bursaphelenchus xylophilus is 0.0265 μL / L at 24 h, and the median lethal concentrations of Meloidogyne incognita and Pratylenchus penetrans are 0.1303 μL / L and 0.01786 μL / L at 72 h respectively; for nano-emulsion immersion, the median lethal concentrations of Bursaphelenchus xylophilus, Meloidogyne incognita and Pratylenchus penetrans are 0.0072 mg / mL, 0.0832 mg / mL and 0.0461 mg / mL respectively. The application provides a new choice for the preparation of a new nematicide.

Description

Technical Field

[0001] This invention relates to the field of agricultural pest and disease control technology, and in particular to the application of a dimethyl trisulfide. Background Technology

[0002] Plant parasitic nematodes are among the major pathogens of infectious plant diseases, causing damage exceeding that of bacteria and viruses, second only to fungal diseases. It is estimated that plant parasitic nematodes cause up to 12.3% of the world's major crop losses annually. The most common and severely damaging nematode genera include root-knot nematodes, cyst nematodes, root-rot nematodes, and pine wood nematodes. Among these, the pine wood nematode is the pathogen causing pine wilt disease, which is extremely destructive to pine trees and seriously threatens forest resources, ecology, and biosecurity, becoming a major national ecological disaster. Chemical control is currently the main method for controlling pine wilt disease, including fumigation of wood packaging materials or pine chips, and trunk injection of pesticides. However, currently only abamectin is registered for the control of pine wood nematodes. Therefore, the development of highly effective, low-toxicity, and environmentally friendly green nematicides is urgently needed.

[0003] Dimethyl trisulfide is a sulfur-containing compound naturally found in the volatiles of cruciferous plants (such as garlic and cabbage) and in the metabolic products of microorganisms (such as Pseudomonas). It has a certain degree of safety for the environment and human health. Studies have found that it has antibacterial activity and disease prevention effects against more than 10 pathogens, including Penicillium citrinum and anthracnose fungus of mango. However, there are currently no reports on its nematode-killing activity against pine wilt nematodes and root rot nematodes. Summary of the Invention

[0004] The purpose of this invention is to provide an application of dimethyl trisulfide, which can effectively kill or control pine wilt nematodes, southern root-knot nematodes, and root rot nematodes.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides the application of dimethyl trisulfide in the preparation of nematicides, wherein the nematicide is used to control pine wood nematode (…). Bursaphelenchus xylophilus Southern root-knot nematode ( Meloidogyne incognita ) or root rot nematodes ( Pratylenchus Filipjev ); The active ingredient of the nematicide is composed of dimethyl trisulfide.

[0006] Furthermore, in the application described, the nematicide is composed of dimethyl trisulfide.

[0007] Furthermore, in the application described, the nematicide consists of dimethyl trisulfide and a pesticide-acceptable carrier.

[0008] Furthermore, in the aforementioned application, the nematicide is in the form of a fumigation preparation.

[0009] Furthermore, in the aforementioned application, the nematicide is in the form of an emulsion.

[0010] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: This invention provides the application of dimethyl trisulfide in the preparation of nematicides. Through the determination of mortality rates against pine wood nematode, southern root-knot nematode, and root rot nematode, it was found that fumigation and soaking with dimethyl trisulfide have good killing effects on all three nematodes. For fumigation, the median lethal concentration (LC50) for pine wood nematode after 24 hours was... 50 The median lethal concentration (LC50) of *Sinapis albopictus* and *Stromboma spp.* at 72 hours was 0.0265 μL / L. 50 The concentrations were 0.1303 and 0.01786 μL / L, respectively; for nanoemulsion immersion, the median lethal concentrations (LC50) for pine wood nematode, southern root-knot nematode, and root-rot nematode were... 50 The concentrations were 0.0072, 0.0832, and 0.0461 mg / mL, respectively. This invention provides a new option for the preparation of novel nematicides. Detailed Implementation

[0011] This invention provides the application of dimethyl trisulfide in the preparation of nematicides, wherein the nematicide is used to control pine wood nematode (…). Bursaphelenchus xylophilus Southern root-knot nematode ( Meloidogyne incognita ) or root rot nematodes ( Pratylenchus Filipjev ); The active ingredient of the nematicide is composed of dimethyl trisulfide.

[0012] In this invention, the active ingredient refers to the component that is effective in controlling pine wilt nematode, southern root-knot nematode, or root-rot nematode. Specifically, dimethyl trisulfide is the sole active ingredient in the nematicide used in this invention.

[0013] In this invention, the nematicide is composed of dimethyl trisulfide.

[0014] In this invention, the nematicide consists of dimethyl trisulfide and a pesticide-acceptable carrier.

[0015] In this invention, the pesticide-acceptable carrier includes, but is not limited to, one of the following: a solvent, a mixture of solvent and adjuvant. The pesticide-acceptable carrier does not have the effect of controlling pine wilt nematode, southern root-knot nematode, or root-rot nematode. Adjuvants include, but are not limited to, one or more of dispersants, co-dispersants, solubilizers, surfactants, and co-surfactants (stabilizers, antioxidants, preservatives, thickeners, defoamers, etc., may also be added as needed). The types of solvents and adjuvants are not limited; categories well-known in the art can be used.

[0016] In this invention, the preferred formulation of the nematicide is a fumigation preparation.

[0017] In this invention, the preferred formulation of the nematicide is an emulsion.

[0018] In this invention, the emulsion formulation preferably includes, but is not limited to, nanoemulsions and granules. The preparation method of the nanoemulsion includes: mixing a surfactant with dimethyl trisulfide to obtain a dispersed phase; mixing water with the dispersed phase and homogenizing and emulsifying to obtain a crude emulsion; and subjecting the crude emulsion to ultrasonic disruption to obtain a dimethyl trisulfide nanoemulsion. The surfactant includes a single surfactant or two or more composite surfactants, and a co-surfactant may optionally be added to the composite surfactant. The types of surfactants and co-surfactants are not limited, and any method well known in the art can be used. Specifically, in the embodiments, the surfactant is selected from Tween 80, and the co-surfactant is selected from anhydrous ethanol. The conditions in the preparation method of the nanoemulsion are not limited, and any method well known in the art can be used.

[0019] In this invention, the methods of using the nematicide include, but are not limited to, fumigation and soaking. Dimethyl trisulfide can be used for fumigation because it has extremely high volatility, allowing it to fully exert its fumigation and nematicidal efficacy.

[0020] In this invention, the sites of action of the nematicide include, but are not limited to, wood packaging materials, pine chips, and soil drenching.

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all 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.

[0022] Example 1

[0023] This embodiment provides a method for determining the bioactivity of dimethyl trisulfide fumigation against different nematodes, including the following steps: The desiccator fumigation method was used. 1 mL of fumigant containing approximately 100 nematodes / mL of pine wood nematode, southern root-knot nematode, and root-rot nematode was added to each 10L desiccator in a petri dish. Different amounts of dimethyl trisulfide stock solution were added to filter paper discs within the desiccator using a pipette, and the desiccator was quickly sealed. Each experimental group was treated in quadruplicates, with a blank control group (no fumigant treatment). After incubation at 25℃ for 24 or 72 hours, nematode mortality was observed and recorded under a dissecting microscope. The fumigation concentrations for pine wood nematode ranged from 0.01 to 0.06 μL / L, for southern root-knot nematode from 0.05 to 0.80 μL / L, and for root-rot nematode from 0.05 to 0.8 μL / L. Nematode mortality and corrected mortality rates were calculated using the following formulas, and the results are shown in Tables 1 to 3.

[0024] Mortality rate (%) = (Number of dead nematodes / Total number of nematodes) × 100%

[0025] Corrected mortality rate (%) = (Experimental mortality rate - Control mortality rate) / (1 - Control mortality rate) × 100%

[0026] Table 1. Fumigation lethality of dimethyl trisulfide against pine wood nematode.

[0027] Table 2. Fumigation lethality of dimethyl trisulfide against southern root-knot nematodes (72h)

[0028] Table 3. Fumigation lethality of dimethyl trisulfide against root rot nematodes (72h)

[0029] The results in Tables 1 to 3 show that dimethyl trisulfide fumigation has a good lethal effect on pine wood nematode, southern root-knot nematode, and root rot nematode. Among them, pine wood nematode is the most sensitive, with a lethal median concentration of 0.0265 μL / L after 24 hours of fumigation; while the lethal median concentrations of southern root-knot nematode and root rot nematode after 72 hours are 0.1303 and 0.01786 μL / L, respectively.

[0030] Example 2

[0031] This embodiment provides a method for determining the bioactivity of dimethyl trisulfide nanoemulsion through immersion in contact with different nematodes, including the following steps: Preparation of dimethyl trisulfide nanoemulsion: A dimethyl trisulfide emulsion was prepared using the following composition: surfactant Tween 80 5% (m / m), co-surfactant anhydrous ethanol 2.5% (m / m), Km=2:1, dimethyl trisulfide 7.5% (m / m), and sterile pure water 85% (m / m). The surfactant Tween 80 and co-surfactant anhydrous ethanol were mixed at a specific mass ratio to obtain a mixed surfactant. Dimethyl trisulfide was added to the mixed surfactant to obtain a mixed phase. The mixture was magnetically stirred at room temperature for 15 min to ensure uniform mixing and obtain a dispersed phase. Deionized water was then uniformly mixed with the dispersed phase at a specific mass ratio and homogenized to emulsify, resulting in a crude emulsion. The crude emulsion was subjected to ultrasonic disruption (300W power, 5 min time, 2 s processing followed by 2 s pause as one cycle) to obtain the dimethyl trisulfide nanoemulsion.

[0032] Pine wood nematode, southern root-knot nematode, and root-rot nematode were prepared into nematode solutions of approximately 200 nematodes / mL. 1 mL of nanoemulsion at different concentrations was mixed with 1 mL of nematode suspension to form experimental groups, while the control group consisted of 1 mL of pure distilled water mixed with 1 mL of nematode solution. Each treatment was repeated four times. After incubating the experimental group samples at 28℃ for 24 h, the 1 mL mixture of each replicate sample was observed under a microscope, and the total number of nematodes and the number of deaths were recorded. Nematode mortality was defined as rigidity and lack of activity upon touch with the nematode's spicule. The immersion concentrations for pine wood nematode ranged from 0.005 to 0.009 mg / mL, for southern root-knot nematode from 0.0167 to 4.05 mg / mL, and for root-rot nematode from 0.02 to 0.08 mg / mL. Nematode mortality and corrected mortality rates were calculated using the following formulas, and the results are shown in Tables 4 to 6.

[0033] Mortality rate (%) = (Number of dead nematodes / Total number of nematodes) × 100

[0034] Corrected mortality rate (%) = (Experimental mortality rate - Control mortality rate) / (1 - Control mortality rate) × 100%

[0035] Table 4. Lethal effect of dimethyl trisulfide nanoemulsion immersion on pine wood nematode (24h)

[0036] Table 5. Lethality of dimethyl trisulfide nanoemulsion immersion against southern root-knot nematodes (24h)

[0037] Table 6. Lethal effect of dimethyl trisulfide nanoemulsion immersion on root rot nematodes (24h)

[0038] The results in Tables 4 to 6 show that the dimethyl trisulfide nanoemulsion has a good lethal effect on pine wood nematode, southern root-knot nematode, and root rot nematode, with lethal concentrations of 0.0072, 0.0832, and 0.0461 mg / mL, respectively.

[0039] In summary, this invention uses dimethyl trisulfide as both a nanoemulsion and a fumigant, which exhibits excellent nematicidal activity against pine wood nematode, southern root-knot nematode, and root-rot nematode, providing a new option for the control of these specific nematode species.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of a dimethyl trisulfide in the preparation of nematicides, characterized in that, The nematicide is used to control pine wilt nematode ( Bursaphelenchus xylophilus Southern root-knot nematode ( Meloidogyne incognita ) or root rot nematodes ( Pratylenchus Filipjev ); The active ingredient of the nematicide is composed of dimethyl trisulfide.

2. The application according to claim 1, characterized in that, The nematicide is composed of dimethyl trisulfide.

3. The application according to claim 1, characterized in that, The nematicide consists of dimethyl trisulfide and a pesticide-acceptable carrier.

4. The application according to any one of claims 1 to 3, characterized in that, The nematicide is formulated as a fumigation preparation.

5. The application according to any one of claims 1 to 3, characterized in that, The nematicide is formulated as an emulsion.

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