Application of maltol in prevention and treatment of plant parasitic nematodes

Abstract

The invention discloses application of maltol in prevention and treatment of plant parasitic nematodes, and relates to the field of biological prevention and treatment of crop diseases, in particular to application of maltol in prevention and treatment of plant parasitic nematodes. The invention aims to solve the technical problem of environmental pollution easily caused by existing chemical agent prevention and treatment. The invention discloses application of maltol in preventing and treating plant parasitic nematodes. The maltol is used for preventing and treating the plant parasitic nematodes. The maltol is 3-hydroxy-2-methyl-4-pyrone, and the maltol is 3-hydroxy-2-methyl-4-pyrone. When the concentration of the 3-hydroxy-2-methyl-4-pyrone is 1.6 g / L, the 24-hour corrected death rate of second-instar larvae of the meloidogyne incognita reaches 90.39%, the LC50 value is 0.46 g / L, the 72-hour corrected death rate reaches 99.61%, and the LC50 value is reduced to 0.023 g / L when the concentration of the 3-hydroxy-2-methyl-4-pyrone is 96 h. When the concentration is 1.6 g / L, the 24-hour corrected death rate of second-instar larvae of the soybean cyst nematode reaches 79.54%, the LC50 value is 0.998 g / L, the 72-hour corrected death rate reaches 91.69%, and the LC50 value is reduced to 0.026 g / L when the concentration is 96 h.

Description

Technical Field

[0001] This invention relates to the field of biological control of crop diseases, and in particular to the application of maltol in the control of plant parasitic nematodes. Background Technology

[0002] Plant nematode diseases are plant diseases caused by the invasion and parasitism of plant-parasitic nematodes. They mainly occur in the roots of crops and are difficult to eradicate once they occur due to their hidden nature. Severe outbreaks can be devastating, especially with continuous planting of host plants. As the number of consecutive years of cropping increases, root-parasitic nematode diseases in these plants become particularly severe.

[0003] In production practice, chemical pesticides are mainly used for pest control. Although chemical control is effective, frequent use easily leads to pesticide resistance, resulting in gradually increasing dosages, raising control costs, and causing serious pollution to the ecological environment. Pesticide residues also pose a significant threat to human health. With increasing awareness of environmental protection and food safety, green food is gaining more and more attention. The ban on highly toxic chemical pesticides is also leading to their withdrawal from the market. Currently, there is an urgent need for safe and efficient biological and bio-based agents to control soil-borne diseases in crops. Plants are rich in insecticidal and bacteriostatic bioactive substances that can resist pathogen invasion, are harmless to beneficial organisms, and are environmentally friendly. The development of new plant-derived pesticides using these substances is of great significance for the green control of nematode diseases. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem that existing chemical agents for pest control can easily cause environmental pollution, and to provide an application of maltol in the control of plant parasitic nematodes.

[0005] The application of maltol in the control of plant parasitic nematodes, wherein the maltol is used to control plant parasitic nematodes.

[0006] The maltol is 3-hydroxy-2-methyl-4-pyranone.

[0007] Maltol is used as an insecticide to kill plant parasitic nematodes.

[0008] The maltol is used to control plant parasitic nematode diseases.

[0009] The plant parasitic nematodes mentioned are the southern root-knot nematode and the soybean cyst nematode.

[0010] The 3-hydroxy-2-methyl-4-pyrone (Maltol), CAS number 118-71-8, with molecular formula C6H6O3, molecular weight 126.112, melting point 160-164℃ (lit.), and boiling point 205℃, is derived from larch. It is a white crystalline powder with a water solubility of 12 g / L (25℃), soluble in ethanol and propylene glycol, and slightly soluble in benzene and ether. It is mainly used as a metal indicator and a flavoring agent in food. The 3-hydroxy-2-methyl-4-pyrone in this invention is derived from a smoking spice, primarily used for marinating grilled meats. Studies have found that the mixture of smoking spices has a strong toxic effect on southern root-knot nematodes and soybean cyst nematodes, and also strongly inhibits the hatching of eggs from both nematodes. Then, metabolomic analysis of the smoked spices revealed that 3-hydroxy-2-methyl-4-pyranone has a good control effect on these two plant nematode diseases.

[0011] The beneficial effects of this invention are:

[0012] In the toxicity test of 3-hydroxy-2-methyl-4-pyranone against second-instar larvae of the southern root-knot nematode (Meloidogyne incognita), the 24-h corrected mortality rate reached 90.39% and the LC50 value was 0.46 g / L at a concentration of 1.6 g / L. The 72-h corrected mortality rate reached 99.61%, and the LC50 value decreased to 0.023 g / L at 96 h.

[0013] In a toxicity test of 3-hydroxy-2-methyl-4-pyranone against second-instar larvae of soybean cyst nematodes (Heterodera glycines, SCN), a concentration of 1.6 g / L resulted in a 24-h corrected mortality rate of 79.54% and an LC50 value of 0.998 g / L. The 72-h corrected mortality rate reached 91.69%, and the LC50 value decreased to 0.026 g / L at 96 h. Inverted microscopic observation revealed significant morphological changes in second-instar SCN larvae after 24 h of treatment with this candidate active substance (1.6 g / L). 3-hydroxy-2-methyl-4-pyranone primarily induced widespread cytoplasmic vacuolation in the larvae, severely impacting the nematode's physiological metabolism.

[0014] In a pot experiment with an inoculation dose of 1000 second-instar larvae per plant for the southern root-knot nematode, drenching tomato roots with 1.6 g / L of 3-hydroxy-2-methyl-4-pyranone showed a control efficacy of 36.73% against the southern root-knot nematode, significantly higher than that of the conventional plant-derived preparation 1.6 g / L matrine (20.62% control efficacy, P<0.05). Meanwhile, this substance had no adverse effects on tomato plant growth.

[0015] In a pot experiment using 1000 second-instar larvae per soybean cyst nematode inoculation dose, drenching soybean roots with 1.6 g / L of 3-hydroxy-2-methyl-4-pyranone showed a control efficacy of 75.16% against soybean cyst nematodes, significantly higher than that of the conventional plant-derived preparation 1.6 g / L matrine (21.43% control efficacy, P<0.05). Simultaneously, this substance had no adverse effects on soybean plant growth. Attached Figure Description

[0016] Figure 1 This is a morphological phenotype of second-instar soybean cyst nematode larvae 24 h after untreated soybean 3-hydroxy-2-methyl-4-pyranone (control group) in Experiment 1.

[0017] Figure 2 This is a morphological phenotype of second-instar soybean cyst nematode larvae treated with 3-hydroxy-2-methyl-4-pyranone for 24 hours in Experiment 1. Detailed Implementation

[0018] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0019] Specific Implementation Method 1: The application of maltol in the control of plant parasitic nematodes in this implementation method, wherein the maltol is used to control plant parasitic nematodes.

[0020] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the maltol used is 3-hydroxy-2-methyl-4-pyranone. Everything else is the same as in Specific Implementation Method One.

[0021] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the maltol is used as an insecticide to kill plant parasitic nematodes. Everything else is the same as in Specific Implementation Method One or Two.

[0022] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the maltol is used to control plant parasitic nematode diseases. Otherwise, it is the same as Specific Implementation Methods One to Three.

[0023] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the plant parasitic nematodes are Southern Root-Knot Nematodes and Soybean Cyst Nematodes. Otherwise, it is the same as Specific Implementation Methods One to Four.

[0024] The following experiments were used to verify the effectiveness of the invention:

[0025] Experiment 1:

[0026] Toxicity test of 3-hydroxy-2-methyl-4-pyranone against second instar larvae of the southern root-knot nematode (Meloidogyne incognita):

[0027] 3-Hydroxy-2-methyl-4-pyranone was prepared into solutions with concentrations of 50 mg / L, 200 mg / L, 800 mg / L, 1600 mg / L, and 5000 mg / L using sterile water. Matrine (Mat) was used as a positive control, and sterile water served as a blank control (CK). 3 mL of each concentration of reagent was injected into 35 mm sterile culture dishes, followed by 50 μL of a suspension of approximately 200 J2 larvae (second instar) of *Symplocos spp.* root-knot nematodes. Three culture dishes were treated per batch and placed in a 28°C dark incubator. Nematode mortality was observed under a microscope at 24 h, 48 h, 72 h, and 96 h, and the corrected mortality rate of J2 larvae was calculated. The experiment was repeated twice.

[0028] Larval mortality rate (%) = number of dead nematodes / total number of tested larvae × 100;

[0029] Corrected larval mortality rate (%) = (Large mortality rate in the treatment group - Larval mortality rate in the control group) / (1 - Larval mortality rate in the control group) × 100.

[0030] The experimental results showed that, in the toxicity test of 3-hydroxy-2-methyl-4-pyranone against the second instar larvae of the southern root-knot nematode (Meloidogyne incognita), the 24-h corrected mortality rate reached 90.39% and the LC50 value was 0.46 g / L at a concentration of 1.6 g / L, the 72-h corrected mortality rate reached 99.61%, and the LC50 value decreased to 0.023 g / L at 96 h.

[0031] Table 1 Effects on the activity of second-instar larvae of the southern root-knot nematode

[0032]

[0033] Experiment 2:

[0034] Toxicity test of 3-hydroxy-2-methyl-4-pyranone against second instar larvae of soybean cyst nematode (Heterodera glycines, SCN):

[0035] The method is the same as in Experiment 1, except that the southern root-knot nematode is replaced with soybean cyst nematode.

[0036] In a toxicity test of 3-hydroxy-2-methyl-4-pyranone against second-instar larvae of soybean cyst nematode (Heterodera glycines, SCN), a concentration of 1.6 g / L resulted in a 24-h corrected mortality rate of 79.54% and an LC50 value of 0.998 g / L. The 72-h corrected mortality rate reached 91.69%, and the LC50 value decreased to 0.026 g / L at 96 h. Inverted microscopic observation showed that treatment with this candidate active substance at 1.6 g / L produced significant morphological phenotypic changes in second-instar SCN larvae 24 h, such as… Figure 1 As shown, 3-hydroxy-2-methyl-4-pyranone primarily causes widespread cytoplasmic vacuolation in larvae, severely affecting the physiological metabolism of nematodes.

[0037] Table 2 Effects on the activity of second-instar larvae of soybean cyst nematode

[0038]

[0039] Experiment 3:

[0040] Pot experiment on Southern Root-Knot Nematode inoculation dose of 1000 second-instar larvae / plant:

[0041] Sterilized and well-mixed sand (volume ratio 1:1) was placed in disposable seedling pots (diameter × height 8 × 12 cm), and three surface-sterilized tomato seeds (variety Zhongshu 4) were sown in each pot. One week after seed germination, one healthy seedling was retained in each pot. Two weeks after sowing, 1000 J2 lines / plant were inoculated, and each plant was simultaneously watered with 20 mL of 3-hydroxy-2-methyl-4-pyranone solution at concentrations of 50 mg / L, 200 mg / L, 800 mg / L, and 1600 mg / L. The conventional control agent was Mat 500×, and the blank control was the same volume of sterile water. Each treatment consisted of 10 pots, and the experiment was repeated twice. The plants were cultivated in a smart greenhouse at a temperature of 22–28℃, a light intensity of 16 h / d, and a humidity of 60%–80%. Forty-two days after inoculation, the fresh weight of roots and the number of root oocytes per plant were investigated by covering the pots, and the inhibition rate per gram of oocytes was calculated, i.e., the control effect.

[0042] Number of root egg masses per gram = Number of root egg masses per plant / Fresh weight of roots per plant

[0043] Control efficacy (%) = (Number of root egg masses per gram in control - Number of root egg masses per gram in treatment) / Number of root egg masses per gram in control × 100

[0044] In a pot experiment with an inoculation dose of 1000 second-instar larvae per plant for the southern root-knot nematode, drenching the roots with 1.6 g / L of 3-hydroxy-2-methyl-4-pyranone showed a control efficacy of 36.73% against the southern root-knot nematode, significantly higher than that of the conventional plant-derived preparation 1.6 g / L matrine (20.62% control efficacy, P<0.05). Meanwhile, this substance had no adverse effects on the growth of tomato plants.

[0045] Experiment 4:

[0046] Pot experiment on soybean cyst nematode inoculation dose of 1000 second-instar larvae / plant:

[0047] The method was the same as in Experiment 3, except that the southern root-knot nematode was replaced with soybean cyst nematode. 21 days after inoculation, the fresh weight of the roots and the number of cysts on the root surface were investigated by covering the pots, and the inhibition rate per gram of root cysts was calculated, which is the control effect.

[0048] Number of root cysts per gram = Number of root surface cysts per plant / Fresh weight of roots per plant

[0049] Control efficacy (%) = (Number of cysts per gram of root in control - Number of cysts per gram of root in treatment) / Number of cysts per gram of root in control × 100%

[0050] In a pot experiment using 1000 second-instar larvae per soybean cyst nematode inoculation dose, 1.6 g / L of 3-hydroxy-2-methyl-4-pyranone applied to the roots showed a control efficacy of 75.16% against soybean cyst nematodes, significantly higher than that of the conventional plant-derived preparation 1.6 g / L matrine (21.43% efficacy, P<0.05). Simultaneously, this substance had no adverse effects on soybean plant growth.

Claims

1. Use of maltol for the control of plant parasitic nematodes, characterized in that The maltol is used for controlling plant parasitic nematodes.

2. Use of maltol according to claim 1 for the control of plant parasitic nematodes, characterized in that The maltol is 3-hydroxy-2-methyl-4-pyrone.

3. Use of maltol according to claim 1 for the control of plant parasitic nematodes, characterized in that The maltol is used as a pesticide to kill plant parasitic nematodes.

4. Use of maltol according to claim 1 for the control of plant parasitic nematodes, characterized in that The maltol is used for controlling plant parasitic nematodes.

5. The use of maltol according to claim 1 for the control of plant parasitic nematodes, characterized in that The plant parasitic nematodes are Meloidogyne incognita and Heterodera glycines.

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