Fungicidal compositions, fungicides and their applications for controlling anthracnose in loofah

Abstract

This invention discloses a fungicidal composition, fungicide, and its application for controlling anthracnose in loofah. The active ingredient of the fungicidal composition is a compound of eugenol and rhein. The combination of eugenol and rhein in the fungicidal composition of this invention has a synergistic effect against the anthracnose pathogen of loofah, which can improve the control effect against anthracnose. Based on this, the dosage of pesticides can be reduced, pesticide residues in loofah can be decreased, and the risk of pesticide resistance can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically relating to a fungicidal composition, fungicide, and its application for controlling anthracnose in loofah. Background Technology

[0002] Cucurbit anthracnose Colletotrichum orbiculare (Berk. & Mont.) Arx can cause anthracnose in loofah, which can damage the leaves, petioles, stems, and fruits. When leaves are affected, the initial symptoms are small, pale yellow, nearly circular spots with indistinct borders. As these spots enlarge, they turn yellowish-brown or brownish-yellow with concentric rings. When dry, the center of the lesions cracks, often forming perforations. In severe cases, the lesions merge into large spots, causing the leaves to wither and die prematurely. When petioles and stems are affected, the lesions are oval or nearly circular, slightly sunken, with dark brown edges. When the lesion encircles the stem or petiole, the stem and leaves above the affected area wilt and die. When fruits are affected, the lesions are circular or irregular, initially yellowish-brown or dark brown, water-soaked, later expanding into brownish-yellow sunken spots, sometimes with concentric rings. In high humidity, they may appear as wet rot.

[0003] Chemical control is currently one of the more effective methods to reduce losses caused by anthracnose in loofah. However, the long-term, continuous, and repetitive use of pesticides has led to varying degrees of resistance in the pathogens causing anthracnose to many currently used agents. Reports indicate that due to these unscientific application methods, the time it takes for resistance to various pesticides to develop is shortening year by year, resulting in a significant increase in both disease control costs and pesticide development costs. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art, especially in the prevention and control of anthracnose in loofah, which is caused by unscientific use of pesticides such as long-term single, continuous and repetitive use. This invention provides a fungicide composition, fungicide and its application that has a synergistic effect, can improve the prevention and control effect of anthracnose in loofah, reduce the dosage of pesticides, reduce pesticide residues in loofah, and reduce the risk of drug resistance.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0006] A bactericidal composition for preventing and controlling anthracnose in loofah, wherein the active ingredient of the bactericidal composition is a compound of eugenol and rhein.

[0007] In the above-mentioned bactericidal composition for preventing and controlling anthracnose in loofah, preferably, the mass ratio of eugenol to rhein is 1-80:20-1.

[0008] More preferably, in the above-mentioned bactericidal composition for preventing and controlling anthracnose in loofah, the mass ratio of eugenol to rhein is 20:1.

[0009] As a general technical concept, the present invention also provides a bactericide, comprising the above-described bactericidal composition for preventing and controlling anthracnose in loofah.

[0010] As a general technical concept, the present invention also provides the application of the above-mentioned bactericidal composition or the above-mentioned bactericide in the prevention and control of anthracnose in loofah.

[0011] Eugenol is a methoxyacrylate protective fungicide with a broad spectrum of activity. Its mechanism of action involves blocking electron transfer between cytochrome b and c, thereby inhibiting mitochondrial respiration, hindering ATP synthesis, and depriving fungi of energy, ultimately leading to a loss of their infectivity. However, due to its single site of action, eugenol is prone to developing resistance when used alone. The inventors discovered through experiments that combining eugenol with rhein has a synergistic effect against anthracnose in cucurbits, which is significant for improving the control efficacy of the fungicide and delaying the development of resistance.

[0012] Compared with the prior art, the advantages of the present invention are as follows: (1) In the bactericidal composition of the present invention, the combination of eugenol and rhein has a synergistic effect on the pathogen of anthracnose of loofah, which can effectively improve the control effect of anthracnose of loofah. Based on this, the dosage of pesticides can be reduced and the pesticide residues in loofah can be reduced.

[0013] (2) The bactericidal composition of the present invention is composed of two active ingredients with different mechanisms of action, which can act on pathogens from different sites of action, making it difficult for pathogens to develop drug resistance, thereby delaying the development of resistance to single-agent drugs and reducing the risk of drug resistance. Detailed Implementation

[0014] The present invention will be further described below with reference to specific preferred embodiments, but this does not limit the scope of protection of the present invention. All materials and instruments used in the following embodiments are commercially available. Unless otherwise specified, all proportions in the following embodiments are by weight percentages.

[0015] Example: Indoor biological experiment 1. Test strain: *Anthracnose cucurbita* Colletotrichum orbiculare (Berk. & Mont.) Arx, collected from diseased loofah leaves, was isolated in the laboratory and preserved on PDA medium.

[0016] 2. Test reagents 96% eugenol technical grade (Jilin Bada Pesticide Co., Ltd.); 98% Chlorophyll technical grade (Shanghai Yuanye Biotechnology Co., Ltd.); The test reagent was first dissolved in dimethyl sulfoxide, then diluted with 0.1% Tween-80 aqueous solution to prepare a single-agent stock solution. Multiple formulations were set up, and five mass concentration gradients were set up for each single agent and formulation mixture according to the proportional method for later use.

[0017] 3. Test Methods The mycelial growth rate method (Mu Liyi 1994) was used. 9 mL of pre-melted PDA medium was added to a sterile Erlenmeyer flask. 1 mL of the drug solution, from low to high concentration, was then quantitatively added to each flask. After thorough mixing, the solution was poured into 9 cm diameter Petri dishes to prepare plates containing the corresponding drug concentrations. A blank control without the drug was also included. Each treatment was replicated five times. Mycelial cakes were cut from the edge of the test strain colonies using a 5 mm punch and inoculated into the center of both the drug-containing and blank control plates. The plates were then covered and incubated at 25°C. When the diameter of the blank control colonies reached 2 / 3 of the Petri dish diameter, the colony diameter was measured using the cross-sectional method, and the inhibition rate of mycelial growth by different treatments was calculated.

[0018] 4. Data Analysis: Statistical analysis was performed using DPS software. Linear regression was conducted with the logarithm of the fungicide concentration as x and the corresponding mycelial growth inhibition rate probability value as y to derive the virulence regression equation and the EC50 virulence of the fungicide against the target pathogen. 50 The value was calculated, and the cotoxicity coefficient (CTC) was calculated according to Sun Yunpei's method.

[0019] 5. Measurement Results The synergistic effect of the drug was evaluated based on the calculated co-toxicity coefficient (CTC). CTC ≤ 80 indicates antagonistic effect, 80 < CTC < 120 indicates additive effect, and CTC ≥ 120 indicates synergistic effect. The results are shown in Table 1-2.

[0020] Table 1. Virulence test results of eugenol and rhein combined with the pathogen causing anthracnose in loofah.

[0021] Table 1 shows that the co-toxicity coefficients of eugenol and rhein against anthracnose of *Luffa cylindrica* are all greater than 120 within a mass ratio of 1-80:20-1 (i.e., 1-80:1-20), indicating a synergistic effect. In particular, when the mass ratio is 20:1, the co-toxicity coefficient reaches 1823.5157, demonstrating a significantly enhanced synergistic effect.

[0022] In summary, the bactericidal composition of the present invention, which combines eugenol and rhein, has a good synergistic effect on the pathogen of anthracnose in loofah, and can improve the control effect of anthracnose in loofah. Based on this, the dosage of pesticides can be reduced and the pesticide residues in loofah can be decreased.

[0023] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A bactericidal composition for controlling anthracnose in loofah, characterized in that, The active ingredient of the bactericidal composition is a compound of eugenol and rhein; the mass ratio of eugenol to rhein is 1-80:20-1.

2. The bactericidal composition for controlling anthracnose in loofah according to claim 1, characterized in that, The mass ratio of eugenol to rhein is 20:

1.

3. A bactericide, characterized in that, Includes the bactericidal composition for controlling anthracnose in loofah as described in claim 1 or 2.

4. The use of a bactericidal composition as described in claim 1 or 2, or a bactericide as described in claim 3, in the prevention and control of anthracnose in loofah.

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