A pesticide composition for preventing and controlling damping-off of wax gourd

Abstract

The present invention belongs to the technical field of pesticides, and particularly relates to a pesticide composition for controlling damping-off of wax gourd. A pesticide composition for controlling damping-off of wax gourd is composed of the binary compounding of hymexazol with furfural, isobutyric acid or benzothiazole. When furfural, isobutyric acid or benzothiazole is compounded with hymexazol in the present invention, the co-toxicity coefficient is greater than 120, showing a synergistic effect, which can improve the control effect on damping-off of wax gourd, reduce the dosage of pesticides applied, and reduce pesticide residues and environmental pollution.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticides, and particularly relates to a pesticide composition for controlling damping-off of wax gourd. Background Art

[0002] The damping-off of wax gourd is caused by the Rhizoctonia solani Kühn AG-4 hyphal anastomosis group. The damping-off of wax gourd mainly occurs in the later stage of seedling raising, when the seedling tray is under relatively high temperature conditions or in direct-seeding fields. It mainly damages the underground roots or the basal part of the seedling stem. Initially, irregular or nearly elliptical dark black spots appear on the diseased part, slightly sunken. After the diseased part spreads around the stem for one week, the stem wilts and dries up, resulting in the death of the melon seedlings. In the early stage, it is similar to damping-off, but damping-off occurs rapidly, while the course of the damping-off of wax gourd progresses more slowly. The diseased part has an indistinct or distinct ring pattern and light brown arachnoid mold, that is, the mycelium or sclerotium of the pathogen, which is different from damping-off.

[0003] Chemical agents are the main means for controlling the damping-off of wax gourd. Common chemical agents include jinggangmycin, hymexazol, thiram, etc. However, long-term application of a single chemical agent is likely to lead to the generation and development of drug resistance, reducing the efficacy of chemical agents. Therefore, it is necessary to screen compound agents with synergistic effects. The inventor found through indoor bioactivity tests that when furfural, isobutyric acid or benzothiazole is compounded with hymexazol, the co-toxicity coefficient against the damping-off pathogen of wax gourd is greater than 120, showing a synergistic effect. There has been no relevant report in this regard so far.

[0004] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a pesticide composition for controlling the damping-off of wax gourd to solve the problems existing in the application of a single chemical agent.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A pesticide composition for controlling the damping-off of wax gourd, which is composed of a binary compound of furfural, isobutyric acid or benzothiazole and hymexazol.

[0008] Preferably, the mass ratio of furfural to hymexazol is 1 - 7:15 - 1.

[0009] Preferably, the mass ratio of isobutyric acid to hymexazol is 1 - 40:1.

[0010] Preferably, the mass ratio of benzothiazole to hymexazol is 1 - 15:20 - 1.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] (1) When furfural, isobutyric acid or benzothiazole is compounded with hymexazol in the present invention, the co-toxicity coefficient is greater than 120, showing a synergistic effect, which can improve the control effect on damping-off of wax gourd, reduce the dosage of pesticides, and reduce pesticide residues and environmental pollution.

[0013] (2) The pesticide composition of the present invention can delay the development of pathogen resistance and reduce the risk of resistance. Detailed implementation manners

[0014] The technical solutions of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0015] Embodiment : Screening of control agents

[0016] 1. Test strains: The wax gourd damping-off pathogen DGLK strain was collected from diseased wax gourd plants, isolated, purified and re-inoculated in the laboratory, identified as Rhizoctonia solani Kühn AG-4, and stored on PDA medium.

[0017] 2. Test agents

[0018] 99.0% furfural, 99.8% isobutyric acid, 99.0% benzothiazole, 98.0% hymexazol. All the above agents are commercially available.

[0019] 3. Test method: Refer to NY / T 1156.2-2006 "Pesticide bioassay guidelines for indoor use - Fungicides - Part 2: Petri dish method for inhibiting mycelial growth of pathogenic fungi".

[0020] 4. Test method

[0021] (1) Preparation of strains: Take out the wax gourd damping-off pathogen DGLK strain from the 4°C refrigerator, inoculate it on PDA medium, and culture it in a constant temperature incubator at 28°C for 3 days for standby;

[0022] (2) First dissolve the technical material with dimethyl sulfoxide, and then dilute it into a single-agent mother liquor; set multiple groups of ratios, and each single-agent mother liquor and the mixed agent of the ratio are set according to a certain proportion, and 5 mass concentration gradients are set for each ratio.

[0023] (3) Mix the medicaments with different concentrations with PDA medium, pour into plates, and prepare culture medium plates containing different concentrations. Use a punch with a diameter of 7 mm to cut the cultured DGLK strains and inoculate them onto the PDA plates containing a series of concentrations of medicaments; use the corresponding dimethyl sulfoxide as a control, and set a blank control. Each treatment has 3 replicates, and all treatments are cultured in a constant temperature incubator at 28 °C.

[0024] 5. Record the results and calculate: When the colony diameter of the blank control grows to about 2 / 3 of the culture dish diameter, measure the colony diameter by the cross method and calculate the inhibition rate of mycelial growth for different treatments. Convert the mycelial growth inhibition rate into probit value (y), convert the medicament concentration (mg / L) into the logarithm with base 10, and use DPS software to obtain the virulence regression equation of each tested medicament, the effective median concentration (EC 50 ), and the correlation coefficient, and calculate the co-toxicity coefficient (CTC value) of the mixture according to the method of Sun Yunpei.

[0025] Mycelial growth inhibition rate = [(control colony diameter - cake diameter) - (treatment colony diameter - cake diameter)] / (control colony diameter - cake diameter) × 100%;

[0026] Actual toxicity index (ATI) = (standard medicament EC 50 ÷ tested medicament EC 50 ) × 100;

[0027] Theoretical toxicity index (TTI) = toxicity index of medicament A × percentage content of A in the mixture + toxicity index of medicament B × percentage content of B in the mixture;

[0028] Co-toxicity coefficient (CTC) = [mixture actual toxicity index (ATI) ÷ mixture theoretical toxicity index (TTI)] × 100.

[0029] According to the classification standard of joint action: co-toxicity coefficient (CTC) ≥ 120 shows synergistic effect; co-toxicity coefficient (CTC) ≤ 80 shows antagonistic effect; 80 < co-toxicity coefficient (CTC) < 120 shows additive effect. The experimental results are shown in Table 1-3.

[0030] Table 1 Indoor biological activity of the compound of furfural and hymexazol against Rhizoctonia solani on wax gourd

[0031]

[0032] As can be seen from Table 1, when furfural and hymexazol are compounded at a mass ratio of 1-7:15-1, the co-toxicity coefficient is greater than 120, showing a synergistic effect, and can improve the control effect on Rhizoctonia solani on wax gourd.

[0033] Table 2 Indoor biological activity of the compound of isobutyric acid and hymexazol against Rhizoctonia solani on wax gourd

[0034]

[0035] As can be seen from Table 2, when isobutyric acid and hymexazol are compounded at a mass ratio of 1-40:1, the co-toxicity coefficient is greater than 120, showing a synergistic effect, and the control effect against Rhizoctonia solani of wax gourd can be improved.

[0036] Table 3 Indoor biological activities of benzothiazole and hymexazol compounded against Rhizoctonia solani of wax gourd

[0037]

[0038]

[0039] As can be seen from Table 3, when benzothiazole and hymexazol are compounded at a mass ratio of 1-15:20-1, the co-toxicity coefficient is greater than 120, showing a synergistic effect, and the control effect against Rhizoctonia solani of wax gourd can be improved.

[0040] In summary, when furfural, isobutyric acid or benzothiazole is compounded with hymexazol in the present invention, the co-toxicity coefficient is greater than 120, showing a synergistic effect, the control effect against Rhizoctonia solani of wax gourd can be improved, the dosage of pesticides can be reduced, and the pesticide residues and environmental pollution can be decreased.

[0041] The foregoing description of the specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the invention and its practical applications, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present invention as well as various different selections and modifications. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A pesticide composition for preventing and controlling damping-off of wax gourd, characterized in that, the pesticide composition is prepared by binary compounding of benzothiazole and hymexazol, and the mass ratio of benzothiazole to hymexazol is 1-15:20-1.

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