A fungicide composition for preventing and treating avocado root rot

Abstract

The application belongs to the technical field of pesticides, and particularly relates to a fungicide composition for preventing and treating oil olive trunk rot. The fungicide composition for preventing and treating oil olive trunk rot is prepared by binary compounding pyridine amide, myclobutanil, mancozeb or trifloxystrobin according to a mass ratio of 1-150:150-1. The pyridine amide is compounded with various existing pesticide components, and the compounding formula of the pyridine amide, myclobutanil, mancozeb or trifloxystrobin is screened out. The pyridine amide, myclobutanil, mancozeb or trifloxystrobin shows a synergistic effect on inhibiting the growth of the pathogenic fungus causing the oil olive trunk rot, can improve the prevention and treatment effect on the oil olive trunk rot, and can further reduce the application dose of the pesticide, relieve the environmental pollution and the pesticide residue.

Description

Technical Field

[0001] This invention belongs to the field of pesticide technology, specifically relating to a fungicide composition for controlling avocado stem rot. Background Technology

[0002] Avocado, also known as butter fruit or alligator pear, is an evergreen tree belonging to the genus *Pyrus* in the family Lauraceae. It is rich in various vitamins, unsaturated fatty acids, and minerals, giving it high nutritional value. Avocado stem rot is one of the major diseases affecting avocados. Its typical symptom is the gradual appearance of water-soaked to brown, irregularly shaped lesions at the stem end. As the fruit ripens, the lesions lengthen, blacken, and become sunken, eventually causing the fruit to shrivel and rot, oozing brown sap and emitting an unpleasant odor, rendering the fruit unmarketable and resulting in economic losses.

[0003] In avocado production, treating immature fruit with fungicides can prevent avocado stem rot. However, due to the long-term unscientific use of fungicides, pathogens have developed varying degrees of resistance, leading to reduced control effectiveness. Furthermore, the application of large doses of pesticides can cause environmental pollution and excessive pesticide residues.

[0004] Florylpicoxamid is a second-generation pyridine amide fungicide developed by DowDuPont (now Corteva). Its CAS Registry Number is 1961312-55-9, and its molecular formula is C2. 27 H 26 F2N2O6, the structural formula is as follows:

[0005]

[0006] Pyridoxam inhibits the respiration and energy synthesis of pathogenic fungi by binding to the Qi ubiquinone (coenzyme Q) binding site on fungal complex III. After application, it is rapidly absorbed by plant tissues and translocated throughout the plant. It can be used on more than 30 crops, including cereals, grapes, fruits, and vegetables, to control powdery mildew, anthracnose, scab, and diseases caused by pathogens such as *Syndrome*, *Botrytis*, *Alternaria*, and *Sclerotinia*. Although pyridoxam has these advantages, as a single-component pesticide, its action site is relatively limited, posing a potential risk of high-level resistance. Combining existing pesticides and screening for formulations with synergistic effects on the target pathogens can improve the control efficacy against the target diseases and reduce the risk of high-level resistance from single-component pesticides, thus providing some protection against pyridoxam.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a fungicide composition for preventing and controlling avocado stem rot, which can improve the control effect on avocado stem rot.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A fungicide composition for preventing stem rot of avocados, wherein the active ingredient of the fungicide composition is a binary compound of pyridabenamide and cyproconazole, mancozeb or oxadiazon in a mass ratio of 1-150:150-1.

[0011] Preferably, the mass ratio of pyridabenamide to cyazofamid is 1-16:4-1.

[0012] Preferably, the mass ratio of pyridabenamide to mancozeb is 1-30:15-1.

[0013] Preferably, the mass ratio of pyridine amide to oxadiazon is 1-10:5-1.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) This invention combines pyridabenamide with various existing pesticide ingredients and screens out a compound formulation of pyridabenamide with cyproconazole, mancozeb or oxadiazon. It shows a synergistic effect on inhibiting the growth of mycelium of the pathogen that causes avocado stem rot, which can improve the control effect of avocado stem rot, thereby reducing the dosage of pesticides and alleviating the problems of environmental pollution and pesticide residues.

[0016] (2) The fungicide composition of the present invention is composed of two pesticide components. Compared with a single component, it can reduce the risk of pesticide resistance and can protect pyridine amide to a certain extent. Detailed Implementation

[0017] The technical solution of this invention patent will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0018] Example

[0019] 1. Test strain

[0020] Avocado fruit samples with stem rot were collected, and the pathogen causing stem rot was isolated in the laboratory and identified as *Lasiodiplodia theobromae*. The pathogen was preserved on a PDA slant at 4°C.

[0021] 2. Test reagents

[0022] 95% pyridaben technical grade, 94% cyazofamid technical grade, 90% mancozeb technical grade, 97.5% azoxystrobin technical grade.

[0023] The test reagent was dissolved in dimethyl sulfoxide and then diluted with 0.1% Tween-80 aqueous solution to prepare a single-agent stock solution with a concentration of 10000 mg / L. Multiple formulations were prepared, and each single-agent stock solution and formulation mixture was prepared with 5 mass concentration gradients according to the proportional method. All the above reagents were prepared and used immediately.

[0024] 3. Test methods

[0025] Using the mycelial growth rate method, pre-melted PDA medium and drug solution were mixed in a sterile Erlenmeyer flask at a volume ratio of 9:1. After thorough mixing, the mixture was poured into 9 cm diameter petri dishes, 10 mL per dish. After cooling, drug-containing plates were formed. A 0.1% (v / v) Tween-80 aqueous solution was included as a blank control. Ten plates were prepared for each treatment.

[0026] The tested strains were propagated on PDA medium at 25°C for 6 days. Mycelial cakes (5 mm in diameter) were punched out and inoculated into the center of a plate (1 cake / plate). The plates were then covered and incubated at 25°C. When the diameter of the blank control colonies reached 2 / 3 of the plate diameter, the colony diameter was measured using the cross-crossing method, and the inhibition rate of mycelial growth by different treatments was calculated.

[0027]

[0028] 4. Data Analysis

[0029] Linear regression was performed with the logarithm of the fungicide concentration as x and the corresponding probability of mycelial growth inhibition as y to derive the virulence regression equation and the EC50 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.

[0030] 5. Measurement Results

[0031] 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 1-3.

[0032] Table 1. Indoor bioactivity assay of pyridaben and cyazofamid combination against Diplosporum cassia.

[0033] Drug Name and Proportion <![CDATA[EC 50 (mg / L)]]> ATI TTI CTC Pyridine amide 0.851 100.000 -- -- cyazofamid 1.271 66.955 -- -- Pyridabenamide 1: Cyazofamid 4 0.633 134.439 73.564 182.751 Pyridabenamide 1: Cyazofamid 1 0.844 100.829 83.478 120.786 Pyridabenamide 4: Cyazofamid 1 0.516 164.922 93.391 176.593 Pyridabenamide 8: Cyazofamid 1 0.362 235.083 96.328 244.043 Pyridabenamide 12: Cyazofamid 1 0.273 311.722 97.458 319.852 Pyridabenamide 16: Cyazofamid 1 0.709 120.028 98.056 122.408

[0034] As shown in Table 1, the co-toxicity coefficients of pyridaben and cyazofamid in inhibiting the mycelial growth of Dispora cocovenenans were all greater than 120 within a mass ratio of 1-16:4-1, indicating a synergistic effect.

[0035] Table 2. Indoor bioactivity assay of pyridaben and mancozeb combined with *Dioscorea bulbifera*.

[0036]

[0037]

[0038] As shown in Table 2, the co-toxicity coefficients of pyridaben and mancozeb in inhibiting the mycelial growth of Dispora cocovenenans were all greater than 120 within a mass ratio of 1-30:15-1, indicating a synergistic effect.

[0039] Table 3. Indoor bioactivity assay of pyridine amide and azoxystrobin combined with Diplosporum cocovenenans.

[0040] Drug Name and Proportion <![CDATA[EC 50 (mg / L)]]> ATI TTI CTC Pyridine amide 0.851 100.000 -- -- Oximetrimer 8.213 10.362 -- -- Pyridabenamide 1: Azoxystrobin 5 1.494 56.961 25.301 225.131 Pyroximide 1: Azoxystrobin 3 2.002 42.507 32.771 129.710 Pyroximil 1: Azoxystrobin 1 1.175 72.426 55.181 131.251 Pyroximil 3: Azoxystrobin 1 0.208 409.135 77.590 527.301 Pyroximide 5: Azoxystrobin 1 0.641 132.761 85.060 156.079 Pyroxim 10: Azoxystrobin 1 0.727 117.056 91.851 127.442

[0041] As shown in Table 3, the co-toxicity coefficients of pyridaben and azoxystrobin in inhibiting the mycelial growth of Dispora cocovenenans were all greater than 120 within a mass ratio of 1-10:5-1, indicating a synergistic effect.

[0042] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. The use of a fungicide composition for controlling avocado stem rot, characterized in that, The active ingredient of the fungicide composition is a binary compound of pyridabenamide and oxadiazon in a mass ratio of 1-10:5-1.

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