Application of dimethyl trisulfide in prevention and treatment of plant parasitic nematodes

Abstract

The invention discloses application of dimethyl trisulfide in prevention and treatment of plant parasitic nematodes, relates to the field of biological prevention and treatment of crop diseases, and aims to solve the problems that existing chemical agents are high in toxicity and easy to cause environmental pollution. The invention finds that the dimethyl trisulfide can kill the meloidogyne incognita and the soybean cyst nematode by poisoning, and the fatality rates of the dimethyl trisulfide to the meloidogyne incognita and the soybean cyst nematode are 100% when the concentration of the dimethyl trisulfide is 2.34 ppm. In addition, dimethyl trisulfide can inhibit hatching of meloidogyne incognita and soybean cyst nematode eggs. The method is used for preventing and treating plant parasitic nematodes.

Description

Technical Field

[0001] The invention relates to the field of biological control of crop diseases, and in particular to application of dimethyl trisulfide in controlling plant parasitic nematodes. Background Art

[0002] Plant nematode disease is a plant disease caused by the invasion and parasitism of plant parasitic nematodes, which mainly occurs in the roots of crops. Due to its hidden nature, it is difficult to eradicate once it occurs. When it occurs seriously, it is devastating, especially when the host plant is planted continuously. With the increase of continuous cropping years, the root parasitic nematode disease of this type of plant is particularly serious.

[0003] In production practice, chemical control is mainly used. Although chemical control has good effects, most chemical nematicides are highly toxic. Pesticide residues in soil and agricultural products exceed the standard from time to time, causing serious pollution to the ecological environment and posing huge risks to human health. With the strengthening of people's awareness of environmental protection and the increasing attention to food safety, green food has received more and more attention. Highly toxic chemical pesticides are banned and highly toxic pesticides are also being withdrawn from the market. At present, there is an urgent need for safe and efficient biological and bio-source preparations to control agricultural plant parasitic nematode diseases. Summary of the invention

[0004] The present invention aims to solve the problem that existing chemical agents are highly toxic and easily cause environmental pollution, and provides the application of dimethyl trisulfide in preventing and controlling plant parasitic nematodes.

[0005] The invention provides application of dimethyl trisulfide in preventing and controlling plant parasitic nematodes.

[0006] The dimethyl trisulfide, CAS No. 3658-80-8, molecular formula C2H6S3, molecular weight 126.26, melting point -68 ° C, boiling point 41 ° C, transparent yellow liquid, used in seasoning, gravy, soup and other food flavors, GB 2760--1996 stipulates that it is a food flavoring allowed for use, usually harmless to water, and is an organic chemical raw material. The present invention finds that the substance is contained in the root tissue extracts of tillering onion (Allium cepa L.) and garlic (Allium sativum L.), and is identified as dimethyl trisulfide by gas chromatography and mass spectrometry (UPLC-MS).

[0007] Furthermore, the dimethyl trisulfide can kill plant parasitic nematodes.

[0008] The plant parasitic nematodes are southern root-knot nematodes and soybean cyst nematodes.

[0009] Furthermore, the dimethyl trisulfide can inhibit the hatching of plant parasitic nematode eggs.

[0010] The plant parasitic nematodes are southern root-knot nematodes and soybean cyst nematodes.

[0011] Beneficial effects of the present invention:

[0012] The invention finds that the substance is contained in the root tissue extracts of tillering onion and garlic, and is identified as dimethyl trisulfide by UPLC-MS.

[0013] Compared with existing chemical agents for controlling nematodes, the present invention found that dimethyl trisulfide has a high toxicity and lethality. Experiments show that when the concentration of dimethyl trisulfide is 2.34ppm, the lethality of southern root-knot nematodes and soybean cyst nematodes is 100%, and dimethyl trisulfide can inhibit the hatching of plant parasitic nematode eggs.

[0014] The dimethyl trisulfide of the present invention does not pollute the environment. The residual amount in the soil is measured 4 months after dimethyl trisulfide is applied to the soil, and it is found that it is equivalent to that of the control group, indicating that the residual amount in the soil does not exceed the standard after the application of dimethyl trisulfide, and does not pollute the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The effect of dimethyl trisulfide on the activity of southern root-knot nematode;

[0016] Figure 2 The effect of dimethyl trisulfide on the activity of soybean cyst nematode;

[0017] Figure 3 The effect of dimethyl trisulfide on the hatching of southern root-knot nematode eggs;

[0018] Figure 4 The effect of dimethyl trisulfide on the hatching of soybean cyst nematode eggs;

[0019] Figure 5 The control effect of dimethyl trisulfide on southern root-knot nematode of tomato and soybean cyst nematode. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below. The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0021] Example 1: Identification of extracts from tillering onion and garlic root tissues:

[0022] Tillering onion and garlic were hydroponically rooted. After 7 days, the roots were washed and the tillering onion and garlic samples were vacuum freeze-dried in a freeze dryer. The freeze-dried samples were ground into powder. 50 mg of sample powder was weighed on an electronic balance, and 1200 μL of 70% methanol water internal standard extract (purchased commercially) pre-cooled at -20°C was added. The sample was vortexed once every 30 minutes for 30 seconds each time, for a total of 6 times. Centrifuge at 12000 rpm for 3 minutes, and the supernatant was aspirated and filtered with a microporous filter membrane (0.22 μm pore size) to obtain onion root tissue extract and garlic root tissue extract, which were stored in injection bottles for UPLC-MS identification and analysis. The tillering onion root tissue extract and the garlic root tissue extract were compared, and it was identified that the two had 768 identical substances in the liquid phase and 64 identical substances in the gas phase. Among them, the content of dimethyl trisulfide was the highest, and further research was carried out.

[0023] The dimethyl trisulfide used in the following experiments is a commercially available product. The dimethyl trisulfide (Dimethyltrisulfide) has a CAS number of 3658-80-8, a molecular formula of C2H6S3, a molecular weight of 126.26, a melting point of -68°C, a boiling point of 41°C, and is a transparent yellow liquid.

[0024] (I) Effects of dimethyl trisulfide on nematode activity:

[0025] In a sterilized 6cm diameter culture dish, 5mL of dimethyl trisulfide dilution was added, and about 1000 second-instar larvae (J2) were added to each dish; the dilution concentration gradient was 2.34mg / mL, 1.17mg / mL, 0.58mg / mL, 0 (sterile water), with a total of 4 treatments, each treatment was repeated 3 times, and stored at 28℃. The number of J2 deaths in each dish was investigated under a stereomicroscope at 1d, 3d, 5d, and 7d, and the nematode mortality and corrected mortality were calculated. This experiment used two nematodes, Meloidogyne incognita (MI) and soybean cyst nematode (Heterodera glycines, SCN), and the two nematodes were experimented separately.

[0026] Mortality rate = number of dead nematodes / total number of nematodes × 100%

[0027] Corrected mortality rate = (treatment nematode mortality rate - control nematode mortality rate) / (1 - control nematode mortality rate) × 100%

[0028] (II) Effects of dimethyl trisulfide on egg hatching:

[0029] In a sterilized 6-cm diameter culture dish, 5 mL of dilution of allelopathic substances was added, and about 1,000 nematode eggs were added to each dish; the concentration gradient of the dilution was 2.34 mg / mL, 1.17 mg / mL, 0.58 mg / mL, and 0 (sterile water), forming 4 treatments, 3 dishes in each treatment, and stored in a constant temperature (28°C) incubator. At 3d, 5d, and 7d, the number of second-instar larvae (J2) hatched in each dish was investigated under a stereomicroscope, and the hatching inhibition rate was calculated using the hatching rate. The entire experiment was repeated twice. This experiment used two types of nematode eggs, the southern root-knot nematode (Meloidogyne incognita) and the soybean cyst nematode (Heterodera glycines, SCN), and the two types of nematode eggs were experimented separately.

[0030] Hatching rate = number of hatched nematodes / number of nematodes and eggs × 100%

[0031] Hatching inhibition rate = (number of nematodes hatched in the control group - number of nematodes hatched in the treatment group) / number of nematodes hatched in the control group × 100%

[0032] (III) The control effect of dimethyl trisulfide on southern root knot nematode disease and soybean cyst nematode disease:

[0033] After the sterilized sand was mixed with soil at a ratio of 2:1, it was placed in a disposable plastic culture pot with a diameter of 8 cm and a depth of 12 cm. One seedling was kept in each pot. When the tomato plant height grew to 10 cm and the soybean seedlings emerged for 8 days, two symmetrical holes were made on both sides of the seedling root system at about 1 cm with a 1 mL micropipette tip. The hole depth was about 4-5 cm. The southern root-knot nematode and soybean cyst line suspension were evenly dripped into the holes with a pipette. 1000 nematodes were inoculated in each plant. After inoculation, the sterilized sand was covered in time. No water was applied for the next 24 hours to prevent the egg suspension from flowing away with the water. At the same time, dimethyl trisulfide solution was irrigated with a concentration of 40 ppm, 20 ppm, 10 ppm, 5 ppm, and 2.5 ppm. 20 ml was irrigated in each pot. The same volume of clean water was used as the control. Each treatment was repeated 5 times. Potted plants were placed in the greenhouse according to a random block design. The entire experiment was repeated twice. The tomato was inoculated for 42 days, and the pots were closed. The number of egg masses on the roots of the plants was recorded, and the control effect was calculated. 21 days after soybean inoculation, the pots were closed to investigate the number of female insects on the root surface and to calculate the control effect.

[0034] Root-knot nematode control effect = (number of control egg masses - number of treated egg masses) / number of control egg masses × 100%

[0035] Control effect of soybean cyst nematode disease = (number of female nematodes on the root surface of the control - number of female nematodes on the root surface of the treatment) / number of female nematodes on the root surface of the control × 100%

[0036] (IV) Experimental results:

[0037] Effects on the activity of southern root-knot nematodes: Experimental results are as follows Figure 1 As shown, it can be seen that at 1 day, with the increase of dimethyl trisulfide concentration, the nematode mortality rate also increased. One day after the start of the experiment, the mortality rate of 0.58ppm to southern root-knot nematode was 90.3%, and the mortality rates of 1.17ppm and 2.34ppm to M. incognita were both 100%, and almost 100% after 3 days.

[0038] Effects on soybean cyst nematode activity: Survey results Figure 2 As shown in the figure, at 1 day, the concentration of dimethyl trisulfide was 1.17ppm, the mortality rate of soybean cyst nematode was 89.1%, the mortality rate of 1.17ppm was 97.9%, and the mortality rate of 2.34ppm was 100%. The higher the concentration, the stronger the lethal effect. It can be seen that the toxic effect of dimethyl trisulfide on the larvae of southern root-knot nematode and soybean cyst nematode is almost the same, and both have strong toxic effects.

[0039] Effect on the hatching of southern root-knot nematode eggs: Dimethyl trisulfide has an inhibitory effect on the hatching of southern root-knot nematode eggs, such as Figure 3 As shown, with the decrease of dimethyl trisulfide concentration, the inhibition rate of incognita root-knot nematode egg hatching also decreased, among which the inhibition rate was the highest when the concentration was 2.34 ppm, reaching about 75% at 3 days.

[0040] Effect on the hatching of soybean cyst nematode eggs: Dimethyl trisulfide inhibits the hatching process of soybean cyst nematode eggs. Figure 4 As shown in the figure, the inhibition on the hatching of soybean cyst nematode eggs increased with the increase of metabolite concentration, and the inhibition rate of 2.34ppm after 5 days could reach more than 60%. It can be seen that at 3 days, the inhibitory effect of dimethyl trisulfide on the hatching of southern root-knot nematode eggs was significantly stronger than that on the hatching of soybean cyst nematode eggs. As time went on, there was little difference in the inhibition rate of the hatching of the two nematode eggs.

[0041] The control effect of dimethyl trisulfide on southern root-knot nematodes in tomatoes and soybean cyst nematodes: Tomatoes were inoculated with southern root-knot nematodes (MI) and watered with five concentration gradients of dimethyl trisulfide. The results of the 42-day pot-drying survey were as follows: Figure 5As shown, the results showed that the control effect of the treatment with 40ppm irrigation was the highest, at 91.6%, and the control effect decreased with the decrease of irrigation concentration. The control effect of 2.5ppm treatment was 40.5%, and all treatments had no adverse effects on tomato growth and development. The control effect of soybean cyst nematode (SCN) was the highest when soybean seeds were coated at sowing and irrigated with 40ppm after emergence, reaching 85.6%. The control effect of 2.5ppm treatment was 23.7%, and the control effect showed a downward trend with the decrease of irrigation concentration, and there was no negative impact on soybean plant height, aboveground fresh weight, and root fresh weight. Overall, the control effect of dimethyl trisulfide on southern root-knot nematode disease in tomatoes was better than that on soybean cyst nematode disease.

[0042] The content of dimethyl trisulfide in the soil was detected 4 months after field application, but the substance was not detected to be significantly higher than that in the control group, as shown in Table 1, indicating that the application of this substance did not cause the residue in the soil to exceed the standard.

[0043] Table 1

[0044]

Claims

1. Application of dimethyl trisulfide in controlling plant parasitic nematodes.

2. The use according to claim 1, characterized in that: The dimethyl trisulfide can poison and kill plant parasitic nematodes.

3. The use according to claim 2, characterized in that: The plant parasitic nematodes are southern root-knot nematodes and soybean cyst nematodes.

4. The use according to claim 1, characterized in that: The dimethyl trisulfide can inhibit the hatching of plant parasitic nematode eggs.

5. The use according to claim 4, characterized in that: The plant parasitic nematodes are southern root-knot nematodes and soybean cyst nematodes.

Images