A biological agent comprising d-limonene for controlling nematodes

Abstract

This invention provides a biological agent for controlling nematodes containing d-limonene, comprising the following components in weight percentage: 1-20% d-limonene, with the remainder being excipients. The biological agent also contains cinnamon oil in a weight percentage of 1-20%. The biological agent prepared by this invention can be used to control crop nematodes, and the combination of d-limonene and cinnamon oil exhibits a significant synergistic effect, effectively reducing the dosage of active ingredients, saving costs, and being environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically relating to a biological agent containing d-limonene for controlling nematodes and its application. Background Technology

[0002] Root-knot nematodes are a type of obligate endoparasitic nematode found worldwide, causing significant damage to plant roots, and are among the most important pathogenic microorganisms in my country. Currently, over 80 effective species of root-knot nematodes have been reported, with particularly severe damage to plants in the Solanaceae, Cucurbitaceae, and Brassicaceae families. With the increasing area of ​​vegetable cultivation year by year, suitable growing environments and continuous cropping practices have exacerbated the problem of root-knot nematode infestations. The long-term prevalence of root-knot nematodes in vegetables has seriously affected vegetable yield and quality, causing substantial economic losses to farmers. Currently, very few pesticides have been registered for the control of root-knot nematode diseases; abamectin and thiazophos are the two most commonly used pesticides by farmers in production practice. Because chemical pesticides are fast-acting, chemical control remains the primary method for controlling root-knot nematodes in vegetable production, with very little application of biopesticides. However, long-term use of single or highly toxic chemical nematicides has led to problems in vegetable cultivation, including increased disease resistance, rising pesticide usage, soil microbial imbalance, and increased pesticide residues in fruits and vegetables. With the growing prominence of food safety and environmental pollution issues, the promotion of biopesticides will gradually increase. Compared to chemical pesticides, biopesticides are less toxic, leave fewer residues, and have better environmental compatibility.

[0003] Limonene, also known as limonene, is a monoterpene compound and a common component of plant essential oils. It is mainly found in citrus fruits such as mandarins, sweet oranges, lemons, tangerines, grapefruits, and kumquats, and is also present in other plants such as peppermint, camphor, cedar oil, pine needles, and spearmint. d-Limonene is the dextrorotatory isomer of limonene. There are currently no reports on the use of d-limonene for nematode control. Furthermore, plant-derived fungicides are less harmful to natural enemies of pests, exhibiting low toxicity and low residue, thus maintaining the high quality of agricultural products. However, the bioactivity of plant-derived fungicides is also relatively low, often requiring compound formulations to seek synergistic fungicidal combinations to improve bioactivity. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides the following technical solution:

[0005] A biological agent containing d-limonene for controlling nematodes is disclosed for use in controlling crop nematodes. The agent comprises 1-20% d-limonene by weight, with the remainder being excipients. Preferably, the d-limonene content is 1-10% by weight; more preferably, it is 1-7% by weight.

[0006] In this invention, the excipients are selected from one or more of the following: lubricant, dispersant, emulsifier, cosolvent, antifreeze, preservative, or solvent. These can be determined from conventional excipients in the art.

[0007] The formulations of the biological agents of this invention are soluble liquids, water-in-oil emulsions, microemulsions, and emulsifiable concentrates. Soluble liquids are preferred.

[0008] The biological agent of this invention also contains cinnamon essential oil, with a weight percentage of 1-20%. A preferred mass ratio of d-limonene to cinnamon essential oil is 1:10-10:1. More preferred mass ratios of d-limonene to cinnamon essential oil are 1:8-8:1, 1:5-5:1, 1:3-3:1, 1:2-2:1, and 1:1.

[0009] This invention relates to a biological agent for the control of nematodes in crops, specifically vegetable crops and root-knot nematodes. It is particularly effective for controlling root-knot nematodes in cucumbers or tomatoes.

[0010] By adopting the above technical solution, the present invention has the following beneficial effects:

[0011] Studies have found that d-limonene has excellent control effects against root-knot nematodes. Furthermore, the combination of d-limonene and cinnamon essential oil exhibits a significant synergistic effect against root-knot nematodes, effectively enhancing the control efficacy of pesticides, reducing the dosage of active ingredients, saving costs, and being environmentally friendly. Detailed Implementation

[0012] The present invention will be further explained below with reference to specific embodiments.

[0013] Example 1: Field control efficacy of d-limonene against tomato root-knot nematodes

[0014] Test crop: Tomato;

[0015] Target pests: Root-knot nematodes;

[0016] Experiment location: Solar greenhouse (the greenhouse was moderately damaged by root-knot nematodes);

[0017] Test reagent: 5% d-limonene soluble concentrate (Puriwan), manufactured by OroAgra International Ltd.;

[0018] Experimental Methods: The experimental method was based on the "Field Efficacy Testing Guidelines for Pesticides (I) - Nematicides for the Control of Root Nematode Diseases". A completely randomized block design was used, with each treatment having a plot area of ​​50 m² and four replicates. A control group was also included. Each pesticide was applied only once at transplanting, mixed with fine sand at the designed dosage. Samples were taken twice, at 45 and 90 days post-application.

[0019] Investigation method: Locate suspected diseased plants and use a five-point diagonal sampling method, surveying two plants at each point. Calculate the control effect based on the disease index.

[0020] Methods for grading diseased plants:

[0021] Grade 0: No insect galls on the roots;

[0022] Grade 1: The root system has a small number of small insect galls;

[0023] Level 3: Two-thirds of the root system is covered with small galls;

[0024] Level 5: The root system is covered with small galls and secondary galls;

[0025] Level 7: The root system forms a cluster of fibrous roots.

[0026] Calculation method

[0027] Disease severity index = 100 × ∑(number of disease roots at each level × relative level value) / (total number of surveys × highest level representative value);

[0028] Relative efficacy = (Control disease index - Treatment disease index) / Control disease index × 100%

[0029] Test results:

[0030] Table 1 shows that all treatments exhibited excellent control efficacy against tomato root-knot nematodes at 45 and 90 days post-application. At 45 days post-application, the control efficacy against tomato root-knot nematodes was 53.3%, 61.6%, and 71.5% at dosages of 1000, 2000, and 3000 g / mu, respectively. At 90 days post-application, the control efficacy was 30.1%, 47.0%, and 58.2% at dosages of 1000, 2000, and 3000 g / mu, respectively. A slight decrease in control efficacy was observed at 45 days post-application, suggesting a second application.

[0031] Table 1: Field control efficacy of d-limonene against tomato root-knot nematodes

[0032]

[0033]

[0034] Note: 1mL is converted to 1g, and the same applies below.

[0035] Example 2: Field control efficacy of d-limonene against cucumber root-knot nematodes

[0036] Test crop: cucumber

[0037] Target pests: root-knot nematodes

[0038] Experiment location: Solar greenhouse (the greenhouse is severely affected by root-knot nematodes)

[0039] Experimental Methods: A completely randomized block design was used, with a plot area of ​​50 m², four replicates per treatment, and a control group. On the day of cucumber transplanting, the dosage was mixed with fine sand according to the experimental design and evenly spread on the seedbed. The medicated sand was then mixed with the top 20 cm of soil using a rake. After ridging and transplanting, the soil was thoroughly watered. Samples were taken twice, at 30 and 60 days post-treatment.

[0040] Survey Methods: A random sampling method was used, with 5 sampling points in each plot, and 2 plants surveyed at each point, for a total of 10 cucumber seedlings. The cucumber roots were dug up to investigate the root-knot nematode disease. Based on the description of the disease symptoms, the root knot level was recorded, and the disease index and control effect were calculated.

[0041] The grading criteria are as follows:

[0042] Grade 0, healthy root system, no root knots;

[0043] Grade 1: The root system has a small number of root knots, with a root knot percentage of less than 25%.

[0044] Grade 3, with a moderate number of root knots on the root system, and a root knot percentage of 25%-50%;

[0045] Level 5, with a large number of root knots on the root system, the percentage of root knots is 50%-75%;

[0046] Level 7: The number of root knots on the root system is particularly large, with a root knot percentage of over 75%.

[0047] Calculation method

[0048] Disease severity index = 100 × ∑(number of disease roots at each level × relative level value) / (total number of surveys × highest level representative value);

[0049] Relative efficacy = (Control disease index - Treatment disease index) / Control disease index × 100%

[0050] Test results:

[0051] Table 2 shows that all treatments exhibited excellent control efficacy against cucumber root-knot nematodes at 30 and 60 days post-application. At 30 days post-application, the control efficacy against cucumber root-knot nematodes was 45.0%, 54.1%, and 67.5% when the dosage of 5% d-limonene soluble concentrate was 1000, 2000, and 3000 g / mu, respectively. At 60 days post-application, the control efficacy against cucumber root-knot nematodes was 32.7%, 40.2%, and 48.8% when the dosage of 5% d-limonene soluble concentrate was 1000, 2000, and 3000 g / mu, respectively. The control efficacy decreased to some extent at 30 days post-application, indicating a second application is recommended.

[0052] Table 2: Field control efficacy of d-limonene against cucumber root-knot nematodes

[0053]

[0054] Example 3: Test on the combined effect of d-limonene and cinnamon essential oil on cucumber root-knot nematodes.

[0055] Test crop: cucumber;

[0056] Target pests: Root-knot nematodes;

[0057] Experimental location: Solar greenhouse;

[0058] Test reagents: self-made, d-limonene and cinnamon essential oil were respectively prepared into soluble liquids.

[0059] 5% d-limonene soluble liquid

[0060] d-Limonene 5% (wt), Agricultural Emulsion 1601# 2% (wt), Tween 80 1% (wt), Termu 2507 3% (wt), Dimethylformamide 10% (wt), Methanol to make up to 100% (wt).

[0061] 5% Cinnamon Oil Soluble Liquid

[0062] Cinnamon essential oil 5% (wt), agricultural emulsion 1601# 2% (wt), Tween 80 1% (wt), Termu 2507 3% (wt), dimethylformamide 10% (wt), methanol to make up to 100% (wt).

[0063] Test method: A completely randomized block design was used, with a plot area of ​​50 m2, four replicates for each treatment, and a control group. On the day of cucumber transplanting, the dosage was mixed with fine sand according to the experimental design and evenly spread on the seedbed. Then, the medicated sand was mixed with the top 20 cm of soil using an iron rake. After ridging and transplanting, the soil was thoroughly watered. Samples were taken 45 days after application for analysis.

[0064] Investigation Methodology: Refer to Example 2

[0065] Combined effects: Actual efficacy > theoretical efficacy by more than 10% synergistic effect; Actual efficacy < theoretical efficacy by less than -10% antagonistic effect; -10% < Actual efficacy < theoretical efficacy by less than 10% summed.

[0066] Test results:

[0067] As shown in Table 3, the combined use of d-limonene and cinnamon essential oil has a significant synergistic effect on cucumber root-knot nematodes, which can effectively improve the control effect of the pesticide on nematodes, effectively reduce the dosage of active ingredients, save costs, and is environmentally friendly.

[0068] Table 3: Test on the combined effect of d-limonene and cinnamon essential oil on cucumber root-knot nematodes

[0069]

[0070]

[0071] Example 4: Soluble Liquid Formulation

[0072] 10% d-limonene·cinnamon essential oil soluble liquid

[0073] d-Limonene 5% (wt), Cinnamon Oil 5% (wt), Agricultural Emulsion 1601# 2% (wt), Tween 80 1% (wt), Termul 2507 3% (wt), Dimethylformamide 10% (wt), Methanol to make up to 100% (wt).

[0074] 12% d-limonene·cinnamon essential oil soluble liquid

[0075] d-Limonene 4% (wt), Cinnamon Oil 8% (wt), Agricultural Emulsion 1601# 3% (wt), Tween 80 2% (wt), Termul 2507 2% (wt), Dimethylformamide 11% (wt), Methanol to make up 100% (wt).

[0076] 14% d-limonene·cinnamon essential oil soluble liquid

[0077] d-Limonene 8% (wt), Cinnamon Oil 6% (wt), Agricultural Emulsion 1601# 4% (wt), Tween 80 2% (wt), Termul 2507 4% (wt), Dimethylformamide 15% (wt), Methanol to make up to 100% (wt).

[0078] 8% d-limonene·cinnamon essential oil soluble liquid

[0079] d-Limonene 5% (wt), Cinnamon Oil 3% (wt), Agricultural Emulsion 1601# 2% (wt), Tween 80 3% (wt), Termul 2507 1% (wt), Dimethylformamide 8% (wt), Methanol to make up to 100% (wt).

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. The use of a biological agent containing d-limonene for controlling nematodes in crops, characterized in that, It contains the following ingredients by weight percentage: d-limonene 1-20%, cinnamon essential oil 1-20%, and the remainder are excipients; The mass ratio of d-limonene to cinnamon essential oil is 1:10-10:

1.

2. The use according to claim 1, characterized in that, The excipients are selected from one or more of the following: lubricant, dispersant, emulsifier, cosolvent, antifreeze, preservative, or solvent.

3. The use according to claim 2, characterized in that, Biological agents are formulated as soluble liquids, water-in-oil emulsions, microemulsions, and emulsifiable concentrates.

4. The use according to claim 1, characterized in that, The crop mentioned is a vegetable crop; the nematode mentioned is a root-knot nematode.

5. The use according to claim 4, characterized in that, The vegetables mentioned are cucumbers or tomatoes.

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