Background
Rhizoctonia solani is a fungal disease caused by Rhizoctonia solani (Rhizoctonia solani), and is one of the important rice diseases in the world. The rice sheath blight disease can occur in the whole growth period of the rice, generally, the disease is heaviest from the beginning of the tillering period to the beginning and the end of heading, leaf sheaths and leaves are endangered, the scion and the stalk are endangered when serious, the disease causes the reduction of the seed setting rate of the rice, the thousand grain weight is reduced, and the yield of the rice is seriously influenced.
The common medicaments for preventing and treating rice sheath blight disease in agricultural production include validamycin, triazolone, hexaconazole and the like, but the long-time use of a single medicament for preventing and treating diseases greatly increases the risk of pathogen resistance, and causes a series of problems of annual decline of prevention effect, pathogen resistance synergism, ecological environment pollution and the like.
The pesticide mixed use is one of effective measures for delaying the drug resistance of agricultural pests. Different pesticides are compounded, so that the generation of pesticide resistance of pests can be delayed, the control effect is improved, the dosage is reduced, and the pollution of the pesticides to the environment is reduced.
CN201610138008.3 discloses a preparation method and application of a pesticide bactericide containing parthenolide, and in particular discloses a preparation method and application of parthenolide to various pathogenic bacteria such as sheath blight germ, sclerotinia rot of rice, sheath blight germ of wheat, small spot germ of corn, rice blast germ, bacterial leaf blight germ of rice, bacterial leaf spot germ of rice and the like, wherein the parthenolide has good efficacy to EC of sheath blight germ of rice 50 36.83mg/L.
At present, no report on the compounding of pyraclostrobin, enestroburin, pyraclostrobin or thifluzamide and parthenolide is found.
Disclosure of Invention
The invention aims to provide a pesticide composition for preventing and treating rice diseases, which solves the problems of reduced prevention effect, enhanced drug resistance, ecological environment pollution and the like caused by long-time use of a single medicament.
In order to achieve the above purpose, the present invention provides the following technical solutions:
the pesticide composition for preventing and treating rice diseases is prepared by compounding pyraclostrobin, enestroburin, pyraclostrobin or thifluzamide and parthenolide in a mass ratio of 1-200:200-1.
Preferably, the mass ratio of the pyraclostrobin to the parthenolide is 1:35-1.
Preferably, the mass ratio of the enestroburin to the parthenolide is 1-5:20-1.
Preferably, the mass ratio of the pyraclostrobin to the parthenolide is 1-30:10-1.
Preferably, the mass ratio of the thifluzamide to the parthenolide is 1-10:45-1.
Preferably, the rice disease is rice sheath blight.
Compared with the prior art, the invention has the following beneficial effects:
when the active ingredients of the pyraclostrobin, the enestroburin, the pyraclostrobin or the thifluzamide and the parthenolide are compounded, the co-toxicity coefficient is more than 120 within a certain mass ratio range, and the synergistic effect is shown. Based on the above, the pesticide composition can effectively control rice sheath blight, can improve the control effect on rice sheath blight compared with a single medicament, is beneficial to reducing the dosage and the pollution of pesticides to the environment, and can provide support for developing novel pesticides.
Detailed Description
The invention will be better understood from the following examples. However, it will be readily appreciated by those skilled in the art that the description of the embodiments is provided for illustration only and should not limit the invention as described in detail in the claims.
Examples: screening of rice sheath blight disease control agent
1. Test strain: rhizoctonia solani (Rhizoctonia solani) was isolated and purified in laboratory from a contaminated rice plant in suburban rice fields in Zhengzhou Henan and stored on PDA medium. ( PDA culture medium formula: peeled potato 200g, sucrose 20g, agar 18g, water 1L, natural pH )
2. Test agent: 98% pyraclostrobin (Canon Black Dragon pesticide Co., ltd.), 90% enestroburin (Shenyang Co., ltd.), 99% pyraclostrobin (Tianjin Alta technologies Co., ltd.), 96% thifluzamide (Zhejiang Tianfeng biosciences Co., ltd.), 98% parthenolide (Shanghai Altin biosciences Co., ltd.).
Dissolving the test reagent with dimethyl sulfoxide solvent, diluting with 0.1% Tween-80 aqueous solution to obtain single-dose mother solution, and setting multiple groups of ratios, wherein each single dose and the ratio mixture have 5 mass concentration gradients according to an equal ratio method.
3. Test method (refer to "pesticide laboratory biological assay test criteria Bactericide part 2: petri dish method for inhibiting growth of pathogenic fungi" Petri dish method)
Adding 9mL of pre-melted PDA culture medium into a sterile conical flask, sequentially quantitatively sucking 1.5mL of liquid medicine from low concentration to high concentration, respectively adding into the conical flask, shaking uniformly, and pouring into 3 culture dishes with the diameter of 9cm in equal quantity to prepare a medicine-containing flat plate with the corresponding concentration; treatments with only 0.1% tween-80 in water were also included as blank, and 3 replicates were set for each treatment.
Cutting bacterial cake at the colony edge of the tested bacterial strain by using a puncher with the diameter of 5mm, inoculating the bacterial cake to the centers of a medicine-containing flat plate and a blank control flat plate, covering a dish cover, and then placing the dish cover at the constant temperature of 25 ℃ for culture. After 48h, colony growth diameter was measured by crisscross method and the inhibition of hypha growth by different treatments was calculated.
4. Data analysis: performing data statistical analysis by DPS software, and linearly regressing with the value of the reagent concentration logarithmic value x and the value of the corresponding hypha growth inhibition rate numerical value y to obtain a virulence regression equation and the virulence EC of the reagent on the target pathogen 50 Values and co-toxicity coefficients (CTCs) were calculated according to the grand cloud Pei method.
Measured virulence index (ATI) = (standard agent EC 50/test agent EC 50) ×100;
theoretical Toxicity Index (TTI) =a agent toxicity index x percentage of agent toxicity index in mixture + B agent toxicity index x percentage of agent toxicity in mixture;
co-toxicity coefficient (CTC) = [ actual drug susceptibility index (ATI)/theoretical drug susceptibility index (TTI) ] x 100.
5. Measurement results
The synergy of the agents was evaluated based on the calculated co-toxicity coefficient (CTC), CTC.ltoreq.80 being antagonism, CTC.ltoreq.120 being additive, CTC.ltoreq.120 being synergy, the results being shown in tables 1-4.
TABLE 1 toxicity determination results of pyraclostrobin and parthenolide compounded Rhizoctonia solani
As can be seen from table 1, at 1:35-1, wherein the co-toxicity coefficient of the pyraclostrobin and the parthenolide after being compounded is greater than 120, and the synergistic effect is shown.
TABLE 2 toxicity determination results of enestroburin and parthenolide compounded Rhizoctonia solani
As can be seen from table 2, at 1-5: within the mass ratio range of 20-1, the co-toxicity coefficient of the compounded enestroburin and the compounded parthenolide to the rhizoctonia solani is more than 120, and the synergistic effect is shown.
TABLE 3 toxicity determination results of pyraclostrobin and parthenolide compounded Rhizoctonia solani
As can be seen from Table 3, at 1-30: within the mass ratio range of 10-1, the co-toxicity coefficient of the pyraclostrobin and the parthenolide after being compounded is greater than 120, and the synergistic effect is shown.
TABLE 4 toxicity determination results of thifluzamide and parthenolide compounded Rhizoctonia solani
As can be seen from Table 4, at 1-10: within the mass ratio range of 45-1, the co-toxicity coefficient of the thifluzamide and the parthenolide after being compounded is greater than 120, and the synergistic effect is shown.
In conclusion, when pyraclostrobin, enestroburin, pyraclostrobin or thifluzamide and parthenolide are compounded, the co-toxicity coefficient is more than 120 within a certain mass ratio range, and the synergistic effect is shown. Based on the above, the pesticide composition can effectively control rice sheath blight, can improve the control effect on rice sheath blight compared with a single medicament, is beneficial to reducing the dosage and the pollution of pesticides to the environment, and can provide support for developing novel pesticides.
The foregoing is merely a preferred embodiment of the present invention, and it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention.