Application of natural unsaturated fatty aldehyde in prevention and control of plant parasitic nematodes

Abstract

The invention discloses application of natural unsaturated fatty aldehyde to prevention and control of plant parasitic nematodes. The natural unsaturated fatty aldehydes are trans-2, 4-heptadienal and trans-2-heptenal, and the natural unsaturated fatty aldehydes are trans-2, 4-heptadienal and trans-2-heptenal. The plant parasitic nematodes are root-knot nematodes, cyst nematodes and pine wood nematodes. The trans-2, 4-heptadienal and the trans-2-heptenal can show excellent nematicidal activity in a contact killing and fumigation mode, a basis is provided for developing a green and environment-friendly nematicide, and the compound has a good application prospect of replacing a traditional chemical nematicide.

Description

Technical Field

[0001] The invention belongs to the technical field of biological control, and in particular relates to application of natural unsaturated fatty aldehydes in controlling plant parasitic nematodes. Background Art

[0002] Plant parasitic nematodes cause economic losses of approximately $157 billion worldwide each year. Among them, root-knot nematodes, cyst nematodes and pine wood nematodes are the three groups with the greatest economic impact. Root-knot nematodes have an extremely wide host range and can parasitize more than 3,000 plant species. Most species of cyst nematodes are host-specific and usually parasitize specific or limited host plants. Pine wood nematodes have the characteristics of a wide variety of host species, fast transmission speed, high mortality rate of diseased pine trees, and difficulty in prevention and control.

[0003] Chemical control is the most common management strategy for controlling plant parasitic nematode diseases. However, the long-term and large-scale application of chemical nematicides poses a huge threat to ecological and environmental safety. Long-term use of chemical pesticides will cause pests to develop resistance, resulting in reduced efficacy. And as resistance increases, higher doses of chemical pesticides need to be used, which further aggravates environmental pollution and health risks. Therefore, the development of environmentally friendly and efficient biological nematicides is an important goal of researchers.

[0004] Natural unsaturated fatty aldehydes are widely present in volatile essential oils of plants, and play an important role in the defense response of plants to pathogenic microorganisms and insects. Natural unsaturated fatty aldehydes usually have an aroma and are natural spices. Trans, trans-2,4-heptadienal and trans-2-heptenal are natural unsaturated fatty aldehydes produced in plants. Trans, trans-2,4-heptadienal and trans-2-heptenal are food spices allowed for use in my country (GB2760), and are also food spices and food preservatives allowed for use by the U.S. Food and Drug Administration (FDA). The present invention has carried out a study on the control effect of trans, trans-2,4-heptadienal and trans-2-heptenal on plant parasitic nematodes, and has shown excellent nematicidal activity through both contact killing and fumigation, has potential nematicidal application value, and is worthy of further development and utilization. Summary of the invention

[0005] In view of this, the object of the present invention is to provide an application of a natural unsaturated fatty aldehyde in preventing and controlling plant parasitic nematodes, wherein the natural unsaturated fatty aldehyde is any one of trans, trans-2,4-heptadienal and trans-2-heptenal. The natural unsaturated fatty aldehyde also has strong volatility in the natural state and can be directly used as a nematode fumigant.

[0006] Preferably, the natural unsaturated fatty aldehyde is trans,trans-2,4-heptadienal and / or trans-2-heptenal.

[0007] Preferably, the natural unsaturated fatty aldehyde is mixed with a synergist to prepare a nematode contact killer for controlling plant parasitic nematodes.

[0008] Preferably, the synergist is methanol and 0.05%-5% Tween solution, the solute of the Tween solution is Tween 20 or / and Tween 80, and the volume fraction of the methanol in the nematode contact killing agent is 1%.

[0009] Preferably, the 0.05%-5% Tween solution is 0.2% Tween 80. Tween 20 is not as effective as Tween 80 in dispersing trans, trans-2,4-heptadienal and trans-2-heptenal, so Tween 80 is preferred.

[0010] Preferably, the plant parasitic nematodes are root-knot nematodes, cyst nematodes or pine wood nematodes, which are the three most harmful groups of plant parasitic nematodes.

[0011] Preferably, the natural unsaturated fatty aldehyde controls plant parasitic nematodes by contact killing and / or fumigation.

[0012] Preferably, the concentration of the natural unsaturated fatty aldehyde used in the contact killing is 1-1000 μg / mL, and the concentration of the natural unsaturated fatty aldehyde used in the fumigation is 0.1-100 μL / L.

[0013] Preferably, the concentration used for contact killing is 200 μg / mL, and the concentration used for fumigation is 0.25 μL / L.

[0014] The natural unsaturated fatty aldehydes trans, trans-2,4-heptadienal and trans-2-heptenal of the present invention have a broad-spectrum nematicidal effect and can be used to prevent and treat the three most harmful plant parasitic nematode groups, root-knot nematodes, cyst nematodes and pine wood nematodes. Natural unsaturated fatty aldehydes are widely present in plants, are green, environmentally friendly, and have strong volatility. They can kill plant parasitic nematodes by contact killing and fumigation dual action modes. Nematode contact killers play a strong role in local space, while nematode fumigants have a wider effective range of action in three-dimensional space, and the nematicidal effect can be enhanced under the dual action mode. The trans, trans-2,4-heptadienal and trans-2-heptenal of the present invention have excellent nematicidal activity, can replace traditional chemical nematicides or chemical nematode fumigants, and have broad application prospects in the field of biological control. DETAILED DESCRIPTION

[0015] The present invention will be described in detail below in conjunction with examples, which are only illustrative and are not limited to the scope of application of the present invention. The present invention is not limited to the following embodiments or examples, and any modifications and deformations made without violating the spirit of the present invention should be included within the scope of the present invention. The experimental reagents used in the following examples can be purchased through commercial channels unless otherwise specified. The natural unsaturated fatty aldehydes trans, trans-2,4-heptadienal and trans-2-heptene aldehyde used in the following examples were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0016] Example 1: Contact activity of natural unsaturated fatty aldehydes against plant parasitic nematodes

[0017] 1) Parasitic nematodes of test plants

[0018] Root-knot nematodes: Root-knot nematode egg masses were separated from the roots of infected tobacco, and the second-instar larvae (J2) were taken for testing 24 hours after hatching.

[0019] Cyst nematodes were isolated from the rhizosphere soil of susceptible soybeans within 24 hours using the Baermann funnel method for testing.

[0020] Pine wood nematodes were tested by separating pine wood nematodes of mixed ages within 24 hours from diseased pine wood blocks using the Baermann funnel method.

[0021] 2) Contact killer

[0022] Trans, trans-2,4-heptadienal and trans-2-heptenal were respectively diluted with an appropriate amount of methanol to increase the solubility, and then diluted with 0.2% Tween 80 solution to prepare aldehyde solutions with concentrations of 50μg / mL, 100μg / mL, 200μg / mL and 400μg / mL. Note that the volume fraction of the amount of methanol in the final prepared aldehyde solution does not exceed 1%. The methanol and Tween 80 in the aldehyde solution prepared by the method of this embodiment will not affect the nematodes. If the concentration is too high, it will affect the nematodes; in addition, Tween 80 has a better dispersing effect on trans, trans-2,4-heptadienal and trans-2-heptenal than Tween 20. The solution prepared by the same steps using an equal amount of ddH2O instead of natural unsaturated fatty aldehydes is used as a control.

[0023] 3) Contact test

[0024] The nematode suspension was adjusted with ddH2O to contain about 50 nematodes per 40 μL. The nematode suspension was added to a single well in a 96-well cell culture plate with the above-mentioned aldehyde solution of different concentrations at a ratio of 1:1 (40 μL and 40 μL) to prepare the test aldehyde solution with a final concentration of 25 μg / mL, 50 μg / mL, 100 μg / mL and 200 μg / mL. Five wells were repeated for each concentration and the plates were treated in a 16°C incubator for 24 h. The mortality rate was calculated and the adjusted mortality rate was calculated. The adjusted mortality rate was calculated as follows:

[0025] Adjusted mortality rate = (mortality rate of treatment group - mortality rate of control group) / (1 - mortality rate of control group) × 100%.

[0026] 4) Result analysis

[0027] The 24h contact activity of trans, trans-2,4-heptadienal and trans-2-heptenal at different concentrations against plant parasitic nematodes, root-knot nematodes, cyst nematodes and pine wood nematodes are shown in Table 1. The results show that the natural unsaturated fatty aldehyde solution of the present invention has excellent contact activity against the three most harmful plant parasitic nematodes within 24 hours at a low concentration, and at a concentration of 200 μg / mL, the corrected mortality rate is all 100%, and can be used to control plant parasitic nematodes at different stages, including the most infectious second-instar larvae and larvae and adults at other instars, and has a broad-spectrum contact activity against plant parasitic nematodes.

[0028] Table 1 Contact activity of natural unsaturated fatty aldehyde solutions against plant parasitic nematodes within 24 hours

[0029]

[0030]

[0031] Example 2: Fumigation activity of natural unsaturated fatty aldehydes against plant parasitic nematodes

[0032] 1) Parasitic nematodes of test plants

[0033] Root-knot nematodes: Root-knot nematode egg masses were separated from the roots of infected tomatoes, and the second-instar larvae (J2) were taken for testing 24 hours after hatching.

[0034] The method for separating cyst nematodes and pine wood nematodes is the same as in Example 1.

[0035] 2) Fumigants

[0036] Trans, trans-2,4-heptadienal and trans-2-heptenal were tested for fumigation and killing nematodes at concentrations of 0.25 μL / L, 0.50 μL / L, 0.75 μL / L and 1.00 μL / L, respectively. Note: 0.25 μL / L means that 0.25 μL of the stock solution of trans, trans-2,4-heptadienal or trans-2-heptenal is used per cubic decimeter of space volume, and the rest are similar.

[0037] 3) Fumigation test

[0038] The nematode suspension was adjusted to contain about 50 nematodes per 100 μL with ddH2O, and 100 μL of nematode suspension was added to each of the three-hole concave glass slides, and then the three-hole concave glass slides were placed in a 1L cube acrylic box (i.e., a space volume of 1 cubic decimeter), and a 3cm×3cm filter paper was pasted on the inner wall of the box. For each treatment, 0.25 μL, 0.50 μL, 0.75 μL and 1.00 μL of trans-2,4-heptadienal and trans-2-heptene aldehyde were dripped on the filter paper, respectively, and an equal amount of ddH2O was used as a control. After the cube acrylic box lid was covered, it was sealed with a PARAFILM film. Then it was placed in a 16°C incubator for treatment for 24 hours, and the corrected mortality rate was calculated, and the calculation method was the same as in Example 1.

[0039] 4) Result analysis

[0040] The 24-h fumigation activities of trans, trans-2,4-heptadienal and trans-2-heptenal at different concentrations against root-knot nematodes, cyst nematodes and pine wood nematodes are shown in Table 2, and the corrected mortality rates are all 100%, indicating that the natural unsaturated fatty aldehydes of the present invention also have excellent broad-spectrum fumigation activities against plant parasitic nematodes at low doses.

[0041] Table 2 Fumigation activity of natural unsaturated fatty aldehydes against plant parasitic nematodes 24

[0042]

[0043] In summary, the natural unsaturated fatty aldehydes trans, trans-2,4-heptadienal and trans-2-heptenal described in the present invention have excellent contact killing and fumigation dual activities against various plant parasitic nematodes and can be used to prevent and control plant parasitic nematodes.

[0044] The conventional techniques and schemes not described in detail in the above embodiments are well known in the art, so they will not be described in detail here. The above embodiments and / or experimental examples describe the preferred embodiments of the present invention in detail, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, the technical scheme of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. The use of natural unsaturated fatty aldehydes in preventing and controlling plant parasitic nematodes, characterized in that: The natural unsaturated fatty aldehyde is any one of trans, trans-2,4-heptadienal and trans-2-heptenal.

2. The use according to claim 1, characterized in that The natural unsaturated fatty aldehyde is trans, trans-2,4-heptadienal and / or trans-2-heptenal.

3. The use according to claim 1, characterized in that The natural unsaturated fatty aldehyde is mixed with a synergist to prepare a nematode contact killer for controlling plant parasitic nematodes.

4. The use according to claim 3, characterized in that The synergist is methanol and 0.05%-5% Tween solution, the solute of the Tween solution is Tween 80 or / and Tween 20, and the volume fraction of the methanol in the nematode contact killing agent is 1%.

5. The use according to claim 4, characterized in that The 0.05%-5% Tween solution is 0.2% Tween 80.

6. The use according to claim 1, characterized in that The plant parasitic nematodes are root-knot nematodes, cyst nematodes or pine wood nematodes.

7. The use according to claim 1, characterized in that The natural unsaturated fatty aldehyde controls plant parasitic nematodes by contact killing and / or fumigation.

8. The use according to claim 7, characterized in that The concentration of the natural unsaturated fatty aldehyde used in the contact killing is 1-1000 μg / mL, and the concentration of the natural unsaturated fatty aldehyde used in the fumigation is 0.1-100 μL / L.

9. The use according to claim 8, characterized in that The concentration used for contact killing is 200 μg / mL, and the concentration used for fumigation is 0.25 μL / L.

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