NY/T 1156.3-2006 Guidelines for Indoor Bioassay Tests for Pesticides Fungicides Part 3: Test for Inhibition of Cucumber Downy Mildew Pathogens Plate Leaf Method NY/T1156.3-2006 Standard Download Decompression Password: www.bzxz.net

ICS65.100
Agricultural Industry Standard of the People's Republic of China
NY/T1156.3—2006
Guidelines for Laboratory Bioassay Tests of Pesticides
Fungicides
Part 3:Petri plate test for determining fungicide inhibition ofPseudoperonospora cubensis growth on detached leavesPublished on July 10, 2006
Implemented on October 1, 2006
Published by the Ministry of Agriculture of the People's Republic of China
"Guidelines for Laboratory Bioassay Tests of Pesticides Fungicides" is a series of standards. This part is the third part of "Guidelines for Laboratory Bioassay Tests of Pesticides Fungicides". This standard is proposed and managed by the Ministry of Agriculture of the People's Republic of China. Drafting unit of this standard: Pesticide Control Institute of the Ministry of Agriculture. The main drafters of this standard are: Xu Wenping, Zhu Chunyu, Zhang Hong, Wu Xinping, Qiu Jianping, Zhang Wei. The Ministry of Agriculture's Pesticide Testing Institute is responsible for the interpretation of this standard. NY/T1156.3—2006
1 Scope
Guidelines for Indoor Bioassay Tests for Pesticides Fungicides NY/T 1156.3—2006
Part 3: Test for Inhibition of Cucumber Downy Mildew by Flat Plate Leaf Method
This part specifies the basic requirements and methods for testing the biological activity of fungicides against cucumber downy mildew by flat plate leaf method. This part is applicable to the indoor test for pesticide registration for the biological activity of fungicides against cucumber downy mildew. Other tests shall be carried out in accordance with this part.
2 Test conditions
2.1 Test target
Cucumber downy mildew (Pseudoberonosbora cubensis). Record the source of the strain. 2.2 Instruments and Equipment
2.2.1 Electronic balance (sensitivity 0.1mg); 2.2.2 Spraying equipment;
2.2.3 Artificial climate box or light moisturizing box; 2.2.4 Biological incubator;
2.2.5 Culture III;
2.2.6 Pipette or pipette, etc.
3 Experimental Design
3.1 Test Material Preparation
Select potted cucumber varieties susceptible to diseases, from the 4th to 6th leaf position from top to bottom, cut the leaves with 1cm to 2cm petioles in the same position and consistent growth, wrap the petioles with wet cotton balls and place them in the culture blood to keep them moist for later use. 3.2 Pharmacy
3.2.1 Test Pharmacy
The test Pharmacy uses the original drug (mother drug), and indicates the generic name, trade name or code, content and manufacturer. 3.2.2 Control Agents
Control agents use registered and commonly used technical drugs in production. The chemical structure type or mode of action of the control agent should be the same or similar to that of the test agent.
3.3 Test Steps
3.3.1 Preparation of Sporangium Suspension
Select diseased leaves, wash the sporangium of downy mildew fungi on the back of the leaves with 47 distilled water, prepare a suspension (the concentration is controlled at 1×105 to 1×107 sporangia per ml), and store at 4℃ for use. 3.3.2 Agent Preparation
Water-soluble agents are directly dissolved and diluted with water. Other agents are dissolved in suitable solvents (such as methanol, ketone, dimethylformamide or dimethyl sulfoxide, etc.) and diluted with 0.05% Tween 80 aqueous solution. According to the activity of the agent, set 5 to 7 series of mass concentrations, and the final content of organic solvents shall not exceed 1%.
NY/T1156.3—2006
3.3.3 Chemical treatment
Evenly spray the liquid on the back of the leaves. After the liquid is naturally blown away, place the leaves of each treatment with the back facing up and place them in a moisturizing box according to the treatment mark. The experiment sets the treatment without chemical as a blank control. 3.3.4 Inoculation and culture
Inoculate 10L of the prepared fresh sporangium suspension on the back of the leaves. Inoculate 4 drops per leaf, and no less than 5 leaves per treatment. In the protective test, inoculate 24h after the chemical treatment, and in the therapeutic test, inoculate 24h before the chemical treatment. After inoculation, cover the dish with a lid and place it in an artificial climate box or a moisturizing box with light. Cultivate it under the conditions of continuous light/darkness alternation of 12h per day, temperature of 17℃～22℃, and relative humidity of more than 90%.
4 Investigation
Measure and record the lesion diameter according to the incidence of the blank control, in meters (mm). 5 Data statistics and analysis
5.1 Calculation method
According to the survey data, calculate the control effect according to formula (1) and express it in percentage (%). The calculation result is retained to two decimal places. P=DoDx100
Where:
P—control effect:
Doblank control lesion diameter;
Dmedicine treatment lesion diameter.
5.2 Statistical analysis
According to the logarithmic value of each drug concentration and the corresponding control efficiency probability value, regression analysis is performed to calculate the ECsD, EC0 and other values ​​of each drug and their 95% confidence limits.
When conducting the combined toxicity test of the drugs, the synergistic coefficient (SR) or co-toxicity coefficient (CTC) of the mixture is calculated according to the Wadley method or Sun Yunpei method to evaluate the type of combined action of the mixture. Wadley method: The synergistic effect of mixed drugs is evaluated based on the synergistic coefficient (SR), that is, SR < 0.5 is antagonistic, 0.5 ≤ SR ≤ 1.5 is additive, and SR > 1.5 is synergistic. The synergistic coefficient (SR) is calculated according to formula (2) and (3): PA + PB
XI = PA/A + Pa/B
Where:
X is the theoretical ECso value of the mixture, in milligrams per liter (mg/L): P is the percentage of A in the mixture, in percentage (%): PB
is the percentage of B in the mixture, in percentage (%): ECso value of A in the mixture, in milligrams per liter (mg/L) B is the ECso value of B in the mixture, in milligrams per liter (mg/L). SR
Where:
Synergistic coefficient of the mixture;
Theoretical ECso value of the mixture, in milligrams per liter (mg/L): Actual ECso value of the mixture, in milligrams per liter (mg/L). (2)wwW.bzxz.Net
NY/T1156.3—2006
Sun Yunpei method: The synergistic effect of mixed drugs is evaluated based on the co-toxicity coefficient (CTC), that is, CTC ≤ 80 is antagonistic, 80 is
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