A biological pesticide for preventing and treating pitaya anthracnose

Abstract

The present application belongs to the technical field of biological fungicides, and particularly relates to a biological pesticide for preventing and treating pitaya anthracnose. The biological pesticide for preventing and treating pitaya anthracnose is prepared by compounding active ingredients of thujapplicin and bacillus subtilis, coniothyrium minitans or trichoderma harzianum. The bacillus subtilis is 200 billion spores / g of bacillus subtilis wettable powder; the coniothyrium minitans is 40 billion spores / g of coniothyrium minitans ZS-1SB wettable powder; and the trichoderma harzianum is 200 million spores / g of trichoderma harzianum LTR-2 wettable powder. When thujapplicin is compounded with bacillus subtilis, coniothyrium minitans or trichoderma harzianum, the combination has a synergistic effect on inhibiting the mycelium growth of pitaya anthracnose fungus within a certain mass ratio range, and can improve the prevention and treatment effect on pitaya anthracnose compared with single components, thereby providing support for developing safe and efficient biological pesticides for preventing and treating pitaya anthracnose, and having important significance for the green development of pitaya.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biological fungicides, and particularly relates to a biological pesticide for preventing and treating pitaya anthracnose. BACKGROUND

[0002] Pitaya is one of the tropical fruits that people like, and belongs to the cactus family of triangular column and Xishixen column plants. Pitaya is rich in nutrients, low in calories, and has many functions such as antioxidant, blood sugar reduction, and eye cooling, and is deeply loved by consumers. In China, pitaya planting is mainly distributed in Guangxi, Guangzhou, Yunnan, Hainan and Fujian provinces. In recent years, with the continuous increase of pitaya planting area, pitaya diseases have become increasingly prominent, mainly including pitaya canker, anthracnose, stem spot, stem rot and black spot, which seriously affect the yield and quality of pitaya.

[0003] In the production process of pitaya, Colletotrichum gloeosporioides, Colletotrichum truncatum and Colletotrichum siamense can cause pitaya anthracnose. At present, chemical agents are mainly used to prevent and control pitaya anthracnose. Chemical agents have the advantages of convenient application and quick effect, but chemical agents have the problems of easy resistance, environmental pollution and pesticide residues. With the improvement of people's living standards, fruit quality and quality safety are paid more attention by people, so it is of great significance to choose safe and efficient biological pesticides to prevent and control pitaya anthracnose for the green development of pitaya.

[0004] Vanillylthioanthracene is a small molecule agent independently developed by Guizhou University Green Pesticide and Agricultural Biological Engineering State Key Laboratory, and its molecular formula is C 19 H 23 O4ClS2, CAS: 2088490-79-1, and its structural formula is:

[0005]

[0006] In order to clarify the application of vanillylthioanthracene, a high-efficiency, low-toxicity and low-residue plant growth regulator, in rice, indoor toxicity determination and field efficacy test were carried out, and it was found that vanillylthioanthracene can inhibit the growth of Magnaporthe grisea mycelium, and has a significant influence on the production of Magnaporthe grisea conidia, spore germination and appressorium formation.

[0007] The inventors found through indoor biological test that when vanilline thioconazole and the existing bacillus subtilis, conidia or trichoderma harzianum are compounded in a certain mass ratio range, the mycelial growth of pitaya anthracnose fungus is inhibited, which can provide support for developing safe and efficient biological pesticides for preventing and controlling pitaya anthracnose. SUMMARY

[0008] The purpose of the present application is to provide a biological pesticide for preventing and controlling pitaya anthracnose, so as to solve the problems existing in the use of chemical pesticides for preventing and controlling plant diseases.

[0009] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0010] A biological pesticide for preventing and controlling pitaya anthracnose, the active ingredient of which is compounded by vanilline thioconazole and bacillus subtilis, conidia or trichoderma harzianum; wherein the bacillus subtilis is bacillus subtilis wettable powder with 200 billion spores / g; the conidia is conidia ZS-1SB wettable powder with 40 billion spores / g; and the trichoderma harzianum is trichoderma harzianum LTR-2 wettable powder with 200 million spores / g.

[0011] As a preferred, the mass ratio of vanilline thioconazole to bacillus subtilis is 1-16:8-1.

[0012] As a preferred, the mass ratio of vanilline thioconazole to conidia is 1-20:40-1.

[0013] As a preferred, the mass ratio of vanilline thioconazole to trichoderma harzianum is 1-30:5-1.

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

[0015] (1) When vanilline thioconazole and bacillus subtilis, conidia or trichoderma harzianum are compounded in a certain mass ratio range, the mycelial growth of pitaya anthracnose fungus is inhibited, which can improve the prevention and control effect on pitaya anthracnose compared with single component, can provide support for developing safe and efficient biological pesticides for preventing and controlling pitaya anthracnose, and has important significance for the green development of pitaya.

[0016] (2) The biological pesticide of the present application is safe to the environment and has low drug resistance risk, which can prolong the update cycle of the pesticide. DETAILED DESCRIPTION

[0017] The technical scheme of the present application will be described below in a clear and complete manner.

[0018] Examples Toxicity determination of the compounded pesticide on pathogenic fungi

[0019] 1. Test strains

[0020] Colletotrichum siamense was isolated from diseased pitaya branches and preserved on PDA medium.

[0021] 2. Test agents

[0022] 95% thiophanate-methyl, 200 billion spores / g Bacillus subtilis wettable powder (Fujian Green An Biological Pesticide Co., Ltd., registration certificate number: PD20130544), 4 billion spores / g Conidiobolus ZS-1SB wettable powder (Hubei Green Sky and Earth Biotechnology Co., Ltd., registration certificate number: PD20190019), 200 million spores / g Trichoderma harzianum LTR-2 wettable powder (Kunming Pesticide Co., Ltd., registration certificate number: PD20212932).

[0023] Thiophanate-methyl was completely dissolved with an organic solvent and then diluted with 0.1% Tween-80 aqueous solution to a single agent stock solution with a concentration of 10,000 mg / L; Bacillus subtilis wettable powder, Conidiobolus ZS-1SB wettable powder, and Trichoderma harzianum LTR-2 wettable powder were diluted with sterile water to a single agent stock solution with a concentration of 10,000 mg / L. Multiple groups of ratios were set up, and each single agent stock solution and the ratio of the mixed agent were set up with 5 mass concentration gradients according to the equal ratio method. All the above liquid medicines were prepared and used immediately.

[0024] 3. Test method

[0025] The mycelial growth rate method was used. The PDA medium at 55℃ and the pesticide solution were mixed uniformly at a volume ratio of 9:1, then poured into Petri dishes with a diameter of 9 cm, 10 mL per Petri dish. After the medium cooled down, the corresponding concentration of the drug-containing plate was formed, and 0.1% Tween-80 aqueous solution was set as the treatment blank control. Each mass concentration of the pesticide solution treatment and the blank control treatment were set up with 5 replicates.

[0026] The test strain was cultured for 4 days at 28℃ in a constant temperature incubator, then a puncher was used to take a 5mm diameter fungus cake at the edge of the expanded colony. The fungus cake was inoculated into the center of the plate with the mycelium facing down using an inoculator, and the Petri dish was covered and placed in a constant temperature incubator at 28℃ for further culture. After 4 days, the colony diameter was measured by the cross method, and the mycelial growth inhibition rate of different treatments was calculated.

[0027]

[0028] 4. Data analysis

[0029] Statistical analysis was performed, using the logarithm of fungicide concentration as x and the corresponding mycelial growth inhibition rate probability value as y, to conduct linear regression analysis, deriving 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 vanillin combined with Bacillus subtilis against Colletotrichum spp.

[0033]

[0034] As shown in Table 1, when vanillin and Bacillus subtilis are combined, the co-toxicity coefficient of inhibiting the mycelial growth of *Colletotrichum spp.*, the anthracnose of dragon fruit, is greater than 120 in the mass ratio range of 1-16:8-1, indicating a synergistic effect.

[0035] Table 2. Indoor bioactivity assays of vanillin combined with *Penicillium scutellarin* and *Penicillium scutellarin* against *Colletotrichum sirenus*.

[0036]

[0037] As shown in Table 2, when vanillin and scutellarin are combined, the co-toxicity coefficient of inhibiting the mycelial growth of *Colletotrichum spp.*, the anthracnose of dragon fruit, is greater than 120 within the mass ratio range of 1-20:40-1, indicating a synergistic effect.

[0038] Table 3. Indoor bioactivity assay of vanillin-sulfuron combined with Trichoderma harzianum against Colletotrichum sirenus.

[0039]

[0040] As shown in Table 3, the co-toxicity coefficient of vanillin and Trichoderma harzianum in inhibiting the mycelial growth of *Colletotrichum spp.*, the anthracnose of dragon fruit, was greater than 120 in the mass ratio range of 1-30:5-1, indicating a synergistic effect.

[0041] In summary, when the present invention's vanillin is combined with Bacillus subtilis, Trichoderma harzianum, or other fungi, it exhibits a synergistic effect on inhibiting the mycelial growth of dragon fruit anthracnose fungi within a certain mass ratio range. Compared with single-component formulations, it can improve the control effect against dragon fruit anthracnose, providing support for the development of safe and efficient biological pesticides for the control of dragon fruit anthracnose, and is of great significance to the green development of dragon fruit.

[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. A biological pesticide for controlling anthracnose in dragon fruit, characterized in that, Its active ingredient is a compound of vanillin and Bacillus subtilis; wherein, the Bacillus subtilis is a wettable powder of Bacillus subtilis with 20 billion spores / g, and the mass ratio of vanillin to Bacillus subtilis is 1-16:8-1.

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