A fungicidal composition for controlling oil palm root rot

Abstract

The present application belongs to the technical field of pesticides, and particularly relates to a fungicidal composition for preventing and treating oil olive root rot. The effective components of the fungicidal composition are formed by binary compounding of fluoximide and berberine or natamycin. When fluoximide and berberine or natamycin are binary compounded, the synergistic coefficient of the fungicidal composition to phytophthora cinnamomi is greater than 1.5, that is, the fungicidal composition exhibits a certain synergistic effect. In particular, when the mass ratio of fluoximide to natamycin is 8:1, the SR value of the fungicidal composition reaches 11.2394, and the synergistic effect is the most significant. Therefore, the fungicidal composition can help to improve the prevention and treatment effect on oil olive root rot, and can be used for developing a high-efficiency fungicide for preventing and treating oil olive root rot. In addition, the fungicidal composition is formed by binary compounding of two effective components, can delay the development of pathogen resistance, and reduce the risk of drug resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pesticides, in particular to a fungicidal composition for preventing and treating avocado root rot. BACKGROUND

[0002] Avocado is also known as Alligator pear, butter fruit and cheese pear, etc., and is a fruit tree of evergreen arbor of Persea Mill. Avocado is a high-energy low-sugar fruit with rich nutrition and good flavor. In the process of avocado planting, it is often damaged by pests and diseases, and avocado root rot caused by Phytophthora cinnamomi is one of the important diseases of avocado. It has a strong invasion ability, and can cause the destruction of the entire avocado plantation when it is serious.

[0003] At present, the prevention and treatment of avocado root rot mainly uses chemical agents. Chemical agents can directly target pathogens and have a quick effect. However, long-term use of single-component chemical agents can easily lead to drug resistance of the disease, and once drug resistance occurs, the prevention and treatment effect will be reduced. The pathogenic bacteria of avocado root rot have developed drug resistance to many existing chemical agents. Although increasing the dosage of the agent can improve the prevention and treatment effect to some extent, it will accelerate the development of drug resistance and increase the pesticide residues in avocado. Compounding different types of agents is an effective way to delay the development of drug resistance of pathogens and improve the prevention and treatment effect.

[0004] Fluazinam is a new type of fluorine-containing benzamide fungicide synthesized by Shandong Zhongnong United Biotechnology Co., Ltd. (Zhongnong United) and Shandong Agricultural University in 2010. Fluazinam is a fluorine-containing benzamide fungicide and also a succinate dehydrogenase inhibitor fungicide. Its mechanism of action is to act on the respiratory chain of fungal mitochondria, inhibit the activity of succinate dehydrogenase, affect the electron transfer in mitochondria, hinder its respiration, and inhibit the main stages of fungal growth and reproduction, such as spore germination, germ tube elongation, mycelium growth and spore mother cell formation. The main prevention and treatment object of fluazinam is oomycete diseases, including cucumber downy mildew, potato late blight and pepper Phytophthora, etc. Due to the fast reproduction speed and strong environmental adaptability of oomycetes, they are prone to drug resistance.

[0005] There is no related report on the compounding of fluazinam and berberine or natamycin.

[0006] The information disclosed in this BACKGROUND section is only intended to increase an understanding of the general context in which the present application can be practiced. It is not admitted that any of the information provided in this section constitutes prior art against the present application. SUMMARY

[0007] The purpose of this invention is to provide a fungicide composition for preventing and controlling root rot in avocados, so as to solve the problems existing when using single-component fungicides to prevent and control root rot in avocados.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A bactericidal composition wherein the active ingredient is a binary compound of fluopyram and berberine or natamycin.

[0010] Preferably, the mass ratio of fluopyram to berberine is 1-9:19-1.

[0011] Preferably, the mass ratio of fluopyram to natamycin is 1-30:50-1.

[0012] Preferably, the mass ratio of fluopyram to natamycin is 8:1.

[0013] The present invention also provides a bactericide comprising the aforementioned bactericidal composition.

[0014] Preferably, the bactericide is in the form of a wettable powder, suspension, or granules.

[0015] The present invention also provides the use of the bactericidal composition in the control of avocado root rot, wherein the pathogen of avocado root rot is Phytophthora cinnamomi.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) When fluopyram is combined with berberine or natamycin in this invention, the synergistic effect against Phytophthora camphorata is greater than 1.5, indicating a certain synergistic effect. In particular, when the mass ratio of fluopyram to natamycin is 8:1, the SR value reaches 11.2394, showing the most significant synergistic effect. Therefore, the fungicidal composition of this invention helps to improve the control effect on avocado root rot and can be used to develop into a highly effective fungicide for the control of avocado root rot.

[0018] (2) The bactericidal composition of the present invention is composed of two active ingredients in a binary compound, which can delay the development of drug resistance in pathogens and reduce the risk of drug resistance. Detailed Implementation

[0019] The present invention can be better understood from the following embodiments. However, those skilled in the art will readily understand that the descriptions in the embodiments are for illustrative purposes only and should not, and will not, limit the invention as detailed in the claims.

[0020] Examples Indoor bioactivity test of a binary compound of fluopyram.

[0021] Test strains: Diseased lateral roots exhibiting typical symptoms of avocado root rot were selected and isolated and purified using tissue isolation. The pathogenicity of the isolated pathogen was determined and identified by pathogenicity testing and identification. The pathogen was identified as Phytophthora cinnamomi and preserved in PDA medium.

[0022] PDA medium formula: 200g potato, 20g glucose, 18g agar, distilled water to a final volume of 1000mL, adjust the pH of the PDA medium to 8 with 1mol / L NaOH solution.

[0023] Test reagents: 98% fluopyram technical grade, 98% berberine technical grade (CAS: 2086-83-1), 95% natamycin technical grade (CAS: 7681-93-8)

[0024] Test method: (Refer to "NY / T 1156.2-2006 Guidelines for Indoor Bioassay of Pesticides - Part 2: Plate Test for Inhibition of Mycelial Growth of Pathogenic Fungi")

[0025] 1. Dissolve the test reagent in dimethyl sulfoxide, and then dilute it separately with 0.1% Tween-80 aqueous solution to prepare single-agent stock solutions. Set up multiple ratios, and set up 7 mass concentration gradients for each single agent and ratio mixture according to the proportional method.

[0026] 2. Add 9 mL of pre-melted PDA medium to a sterile conical flask. Quantitatively add 1 mL of drug solution from low to high concentration to the conical flasks, shake well, and pour into 9 cm diameter petri dishes to prepare drug-containing plates of the corresponding concentrations. A blank control without drug is also provided. Five replicates are set up for each treatment.

[0027] 3. Using a punch, cut a 5mm diameter mycelial cake from the edge of the colony of the propagated test strain, inoculate it in the center of the drug-containing plate and the blank control plate, cover the plate and place it in a constant temperature incubator at 28℃.

[0028] 4. When the diameter of the blank control colonies reaches more than 1 / 2 of the petri dish diameter, measure the colony diameter with calipers. Measure the diameter of each colony vertically once using the cross-sectional method, and take the average value. Calculate the mycelial growth inhibition rate for each treatment based on this average value.

[0029] 5. Data 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 of the fungicide against the target pathogen. 50 The synergistic effect coefficient (SR) of the mixture was calculated according to the Wadley method to evaluate the type of combined action of the mixture. The results are shown in Table 1.

[0030] The calculation methods for mycelial growth inhibition rate, synergistic coefficient, and evaluation methods for the synergistic effect of pesticide mixtures are based on "NY / T 1156.2-2006 Guidelines for Indoor Bioassay Tests of Pesticides - Fungicides Part 2: Plate Method for Inhibition of Mycelial Growth of Pathogenic Fungi".

[0031] Table 1. Evaluation of the efficacy of fluopyram combined with Phytophthora camphorata.

[0032]

[0033]

[0034] As shown in Table 1, when fluopyram is combined with berberine or natamycin in a binary formulation, the synergistic effect on *Phytophthora camphorata* is greater than 1.5 within the set mass ratio range, indicating a certain synergistic effect. In particular, when the mass ratio of fluopyram to natamycin is 8:1, the SR value reaches 11.2394, showing the most significant synergistic effect.

[0035] 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. A bactericidal composition, characterized in that, Its active ingredient is a binary compound of fluopyram and berberine; the mass ratio of fluopyram to berberine is 1-9:19-1.

2. A bactericide, characterized in that, The bactericide includes the bactericidal composition according to claim 1.

3. The bactericide according to claim 2, characterized in that, The bactericide is formulated as a wettable powder, suspension, or granules.

4. The use of the bactericidal composition according to claim 1 in the control of avocado root rot, characterized in that, The pathogen causing the root rot of avocados is Phytophthora camphorata (Phytophthora camphor Phytophthora cinnamomi ).

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