BACTERICIDAL COMPOSITION FOR CONTROLLING GUMMY STEM BLIGHT OF MELONS

Abstract

The present invention discloses a bactericidal composition for controlling gummy stem blight of melons. The bactericidal composition includes an active ingredient composed of Pydiflumetofen and Thifluzamide. An appropriate amount of agricultural bactericide adjuvant is added into the bactericidal composition to be prepared into a common agricultural bactericide dosage form. The two components in the present invention have no cross resistance. After combined according to a certain ratio, the two agents have an obvious synergistic effect, and have a more excellent effect of controlling fungal diseases of crops. Due to the combined use, the dose may be decreased; drug resistance of pathogenic bacteria to a single agent may be delayed; ecological damage and environmental pollution are effectively decreased; and crop yield and quality can be increased. The composition widens a disease resistance spectrum.

Claims

1. A bactericidal composition for controlling gummy stem blight of melons, wherein a bactericide is composed of Pydiflumetofen and Thifluzamide, and a mass ratio of the Pydiflumetofen to the Thifluzamide is 20:1-1:20.

2. The bactericidal composition according to claim 1, wherein the mass ratio of the Pydiflumetofen to the Thifluzamide is 5:1-1:5.

3. The bactericidal composition according to claim 1, wherein an active ingredient of the Pydiflumetofen and the Thifluzamide accounts for 1-80% of the total mass of the bactericidal composition; and by adding an appropriate amount of agricultural bactericide adjuvant, the bactericidal composition is prepared into suspension, wettable powder, microcapsules, water dispersible granules or suspended seed coatings.

4. The bactericidal composition according to claim 2, wherein an active ingredient of the Pydiflumetofen and the Thifluzamide accounts for 1-80% of the total mass of the bactericidal composition; and by adding an appropriate amount of agricultural bactericide adjuvant, the bactericidal composition is prepared into suspension, wettable powder, microcapsules, water dispersible granules or suspended seed coatings.

5. A use of the bactericidal composition of claim 1 in controlling gummy stem blight of melons, wherein the bactericidal composition simultaneously controls the fungal diseases of powdery mildew, leaf spot disease, brown spot or gray mold.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] The present invention will be further described below in combination with embodiments. However, contents of the present invention are not limited to the embodiments below.

[0014] Embodiment 1 Indoor toxicity test of Pydiflumetofen and the Thifluzamide on Stagonosporopsis cucurbitacearum

[0015] Bactericidal properties of the Pydiflumetofen and the Thifluzamide were analyzed in detail. EC50 (drug safety index) of two single components such as the Pydiflumetofen and the Thifluzamide (hereinafter referred to as agents) was tested first; a combination ratio of the two agents was set by a Wadley method according to the EC.sub.50 of the two single agents, and according to a Wadley synergistic coefficient SR value.

[0016] A test object was Stagonosporopsis cucurbitacearum of melons, but was not limited herein. The Pydiflumetofen and the Thifluzamide were taken; a PDA solid medium was selected and prepared into a plate with drug liquid needs; each dish had a volume of about 18 ml; and hypha blocks having a diameter of 5 mm were prepared on the edges of pre-culture colonies by using a sterilized puncher and respectively transferred onto different medium plates to be cultured at 25° C. Hypha growth assay was adopted during the test; drug containing media were prepared according to different treatments; hypha blocks having a diameter of 5 mm were prepared on the edges of the pre-culture colonies by using the sterilized puncher and respectively transferred onto medium plates with different drug content; a colony diameter was tested by a crossing method; the colony diameter (mm) was measured; and a growth inhibition ratio was calculated by the following formula:

hypha growth inhibition ratio%=(1−(agent treatment colony diameter 5)/(control colony diameter 5)×100%

[0017] The hypha growth inhibition ratio was converted into an inhibition probability value (y); an agent concentration was converted into a concentration logarithm (x); a toxicity regression line was drawn by taking the concentration logarithm as a horizontal coordinate and taking the probability value as a vertical coordinate; toxic regression equations of the single agents such as the Pydiflumetofen and the Thifluzamide and a mixture thereof on the pathogenic bacteria were solved; and the EC.sub.50 value and a correlation coefficient value r were calculated.

[0018] Interaction of the mixture was evaluated according to the Wadley method; and a calculation formula was as follows:

EC.sub.50(theoretical value)=(a+b)/(a/EC.sub.50a+b/EC.sub.50b);

SR=EC.sub.50 (theoretical value)/EC.sub.50 (actual value).

[0019] In the formula, a and b were content ratios of various components in the mixture; and a mixing effect was analyzed based on the value SR. When SR≤0.5, the mixture of the two agents had antagonism; when SR=0.5-1.5, the mixture of the two agents had an addition effect; and when SR≥1.5, the mixture of the two agents had a synergistic effect.

TABLE-US-00001 TABLE 1 Toxicity test results of the single agents of the Pydiflumetofen and the Thifluzamide and the mixture thereof on Stagonosporopsis cucurbitacearum EC.sub.50 Correlation EC.sub.50 (theoretical) Ratio (P:B) Regression equation coefficient (r) ppm ppm SR Pydiflumetofen (P) y = 7.8972 + 1.4753x 0.9919 0.0109 Thifluzamide (B) y = 6.7046 + 1.2667x 0.9883 0.0451 15:1  y = 7.6095 + 1.3758x 0.998 0.0127 0.0114 0.8995 10:1  y = 7.5778 + 1.3105x 0.9944 0.0108 0.0117 1.0840 5:1 y = 7.5628 + 1.2261x 0.9879 0.0081 0.0125 1.5404 1:1 y = 7.4857 + 1.2396x 0.9876 0.0099 0.0176 1.7734 1:5 y = 7.0222 + 1.1693x 0.9787 0.0186 0.0296 1.5921  1:10 y = 6.8054 + 1.1724x 0.9942 0.0288 0.0351 1.2184

[0020] It can be seen from the above table that, the composition of the Pydiflumetofen and the Thifluzamide at different ratios had different bacteriostatic effects on the Stagonosporopsis cucurbitacearum. Experimental results showed that, the Pydiflumetofen and the Thifluzamide had the addition effect in a mass ratio range of 15:1-1:10, and had the synergistic effect in the ratio range of 5:1-1:5.

[0021] Indoor combined action determination results showed that, the composition of the Pydiflumetofen and the Thifluzamide has an excellent growth inhibition effect on the Stagonosporopsis cucurbitacearum. A significant synergistic effect exists between the two components. When compounded according to a certain ratio, the two components may decrease the dose and effectively decrease ecological damage and environmental pollution, and can improve yield and quality of the crops. In the present invention, both the Pydiflumetofen and the Thifluzamide have low toxicity and are safe to the people and livestock, beneficial organisms and the environment. The Pydiflumetofen and the Thifluzamide have no cross resistance and also have different bactericidal spectrums. When mixed in use, the two components may delay the drug resistance of the pathogenic bacteria on the single agents and widen the anti-disease spectrum of the crops, and achieve aims of control and drug decrease.

Embodiment 2: Preparation Embodiments

Preparation Embodiment 1

Preparation Method of 18% Pydiflumetofen.Math.Thifluzamide Water Dispersible Granules: in Percentage by Mass

[0022] 15% of Pydiflumetofen, 3% of Thifluzamide, 6% of sodium lignin sulfonate, 4% of polyvinyl alcohol, 8% of ammonium sulfate, 10% of white carbon black and the balance of kaolin.

[0023] Preparation method: the above components were uniformly mixed in a mixer according to a formula ratio and then subjected to air jet pulverization; a small amount of purified water was added after completion of pulverization to fully and uniformly stir the components; and the mixture was subjected to extruding granulation and then dried, thereby obtaining the water dispersible granules.

Preparation Embodiment 2

Preparation Method of 20% Pydiflumetofen.Math.Thifluzamide Suspension: in Percentage by Mass

[0024] 10% of Pydiflumetofen, 10% of Thifluzamide, 6% of calcium lignosulphonate, 4% of alkyl phenol polyoxyethylene phosphate, 0.1% of xanthan gum, 0.3% of an organic silicon defoamer and the balance of water.

[0025] Preparation method: according to the formula, the above components were weighed according to a ratio; the components were ball-milled in a ball mill for 30 minutes and filtered; the components were extracted into a dispersing tank for high-speed shearing for 3 minutes and then fully ground by a sand mill; the diameter of solid component particles was controlled within 2 microns; and the components were uniformly stirred after completion of grinding, thereby obtaining the suspension.

Preparation Embodiment 3

Preparation method of 12% Pydiflumetofen.Math.Thifluzamide Water Dispersible Granules: in Percentage by Mass

[0026] 2% of Pydiflumetofen, 10% of Thifluzamide, 6% of sodium lignin sulfonate, 4% of polyvinyl alcohol, 8% of ammonium sulfate, 10% of white carbon black and the balance of kaolin.

[0027] Preparation method: the above components were uniformly mixed in a mixer according to a formula ratio and then subjected to air jet pulverization; a small amount of purified water was added after completion of pulverization to fully and uniformly stir the components; and the mixture was subjected to extruding granulation and then dried, thereby obtaining the water dispersible granules.

Preparation Embodiment 4

[0028] Preparation method of 8% Pydiflumetofen.Math.Thifluzamide suspended seed coatings: in percentage by mass.

[0029] 4% of Pydiflumetofen, 4% of Thifluzamide, 3% of xanthan gum, 8% of a dispersing agent FS3000, 4% of 5-lauryl sodium sulfate, 3% of sodium lignin sulfonate, 3% of glycerol, 5% of bentonite, 2% of Dioctylsulfosuccinate sodium, 3% of a film-forming agent, 2% of a dye and the balance of water.

[0030] Preparation method: according to the formula, the above components (except for the film-forming agent and the dye) were weighed according to a ratio; the components were ball-milled in a ball mill for 60 minutes and filtered; the components were extracted into a dispersing tank for high-speed shearing for 3 minutes and then fully ground by a sand mill; the diameter of solid component particles was controlled within 1 μm; the components were uniformly stirred after completion of grinding; and the film-forming agent and the dye were added, thereby obtaining the suspended seed coatings.

Embodiment 3: Field Control Experiment of Pydiflumetofen and the Thifluzamide on Gummy Stem Blight of Trichosanthes kirilowii maxim

[0031] Control tests of gummy stem blight of Trichosanthes kirilowii maxim were respectively conducted in 2020 and 2021. Test data in 2021 were collected as follows: the 20% Pydiflumetofen.Math.Thifluzamide suspension, 20% Pydiflumetofen suspension, 30% Thifluzamide suspension and 25% Azoxystrobin suspension in embodiment 2 were respectively used in the experiment. The variety of the tested Trichosanthes kirilowii maxim was “Wanlou 9”; the test location was a Trichosanthes kirilowii maxim field in Gangji experimental production base in Anhui Academy of Agricultural Sciences; water consumption per mu was 30 kg; the Trichosanthes kirilowii maxim was subjected to agent control at an early stage of growing and flowering (May 20); and disease condition survey was conducted within 30 days (Table 2).

TABLE-US-00002 TABLE 2 Control effects of different compound dosage forms on the gummy stem blight of Trichosanthes kirilowii maxim Disease Control First dose Incidence control object Treatment agent (g.a.i/ha) rate (%) effect (%) Gummy stem 20% 150 2.88 93.18 blight of Pydiflumetofen .Math. Trichosanthes Thifluzamide kirilowii suspension maxim 20% Pydiflumetofen 150 16.59 79.05 suspension 30% Thifluzamide 150 21.34 69.58 suspension 25% Azoxystrobin 150 39.64 55.25 suspension Blank control — 62.27 —

[0032] Field experiment results showed that, the Pydiflumetofen and the Thifluzamide have significant control effects the on gummy stem blight of Trichosanthes kirilowii maxim, and have better control effects than the Azoxystrobin. A pesticide formulation combined according to a synergistic ratio has a more excellent overall control effect on the gummy stem blight of the Trichosanthes kirilowii maxim, and has the control effect higher than that of a single dosage form. According to field investigation, crop growth is normal in a test dose range; no plant has any disease or abnormal phenomena; and the pesticide formulation is safe to the Trichosanthes kirilowii maxim.

Embodiment 4: Field Control Experiment of Pydiflumetofen and the Thifluzamide on Gummy Stem Blight of Watermelon

[0033] Control tests of gummy stem blight of watermelons were respectively conducted in 2020 and 2021. Test data in 2021 were collected as follows: the 18% Pydiflumetofen.Math.Thifluzamide water dispersible granules, 20% Pydiflumetofen suspension, 30% Thifluzamide suspension and 25% Azoxystrobin suspension in embodiment 1 were respectively used in the experiment. The variety of the tested watermelon was “Zaojia 8424”; the test location was a watermelon greenhouse in Gangji experimental production base in Anhui Academy of Agricultural Sciences; water consumption per mu was 30 kg; the watermelons were subjected to agent control for the first time within 30 days after field planting of watermelon seedlings, and then subjected to agent control for the second time within 10 days after the first control; and disease condition survey was conducted within 30 days after the second agent control (Table 3).

TABLE-US-00003 TABLE 3 Control effects of different compound dosage forms on the gummy stem blight of the watermelon Second Disease Control First dose dose Incidence control object Treatment agent (g.a.i/ha) (g.a.i/ha) rate (%) effect (%) Gummy stem 18% 120 100 1.85 94.18 blight of the Pydiflumetofen .Math. watermelon Thifluzamide water dispersible granules 20% Pydiflumetofen 120 100 13.08 80.25 suspension 30% Thifluzamide 120 100 12.64 79.58 suspension 25% Azoxystrobin 120 100 28.04 68.55 suspension Blank control — — 63.08 —

[0034] Greenhouse experiment results showed that, the Pydiflumetofen and the Thifluzamide have significant control effects the on gummy stem blight of the watermelon, and have better control effects than the Azoxystrobin. A pesticide formulation combined according to a synergistic ratio has a more excellent overall control effect on the gummy stem blight of the watermelon, and has the control effect higher than that of a single dosage form. According to field investigation, crop growth is normal in a test dose range; no plant has any disease or abnormal phenomena; and the pesticide formulation is safe to the watermelon.

[0035] Finally, it should be noted that, the above listed examples are merely several specific embodiments of the present invention. Apparently, the present invention is not limited to the above embodiments, and may have many variations. All variations that can be directly derived or thought from the contents of the present invention by those ordinary skilled in the art are regarded as the protection scope of the present invention.