GB/T 17980.45-2026Pesticides - Guidelines for field efficacy trials - Part 45: Herbicides against weeds in rapeseed (English PDF)

5.2 Reagents

5.2.1 Test reagents The test reagent treatment includes four dosages. high, medium, low, and twice the medium dose. Additional dosages may be set according to experimental requirements in special cases. Specify the reagent dosage. Text/English generic name or code, dosage form, active ingredient content, manufacturer, production date or batch number, etc.

5.2.2 Control reagent The control agent should be a registered, locally commonly used product with good efficacy and safety in actual use. The type and action of the control agent should be specified. The formulation and herbicidal spectrum should be the same as or similar to the test agent, and the registered dosage and application method should be used. If the test agent is a mixture, it should also be... Each active ingredient, in single-dose form, serves as a control. Specific measures may be taken depending on the purpose of the experiment. Record the Chinese/English generic name, dosage form, active ingredient content, manufacturer, registration number, production date or batch number, and application rate of the control drug. Dosage, etc.

5.3 Community Arrangement

5.3.1 Layout of the community Different treatment plots in the experiment were arranged in a randomized block design. In special cases, comparative, in-between, or irregular arrangements may be used. Please provide an explanation.

5.3.2 Area of the community and duplication The area of the residential area is 20m2~30m2, and the shape of the residential area is rectangular. Number of repetitions. no less than 4 repetitions.

7.1 Weed Survey

7.1.1 Survey Methodology Describe in detail the symptoms of weed damage (such as growth inhibition, chlorosis, deformity, etc.) to accurately explain the mechanism of action of the herbicide. Investigate weed species, number of plants, coverage, and biomass (fresh weight of aboveground parts) in each treatment area. Use the following absolute number survey method or estimated value adjustment. Search method.

a) Absolute number survey method (numerical measurement) Investigate the total number of plants or biomass (fresh weight of aboveground parts) for each weed species. In special cases, the number of specific organs of the weed may also be investigated (e.g., (e.g., the number of tillers in grassy weeds). Conduct a survey of the entire plot or take 3-5 sampling points in each plot, with each sampling point... A sampling survey was conducted at a scale of 0.25m^2 to 1m^2.

b) Estimated value survey method (visual inspection) Each herbicide-treated patch was compared with a control patch in the same block to estimate the relative weed population. The total weed community population could be used as a reference. It is expressed by indicators such as the quantity, coverage, and height of a single type of weed. The estimated results can be expressed as a simple percentage (0 for no weeds, 100% for the same weeds as the control area), or they can be converted to equivalent quantities. The percentage of weed control effect is indicated (0 for no control effect, 100% for complete weed control). The blank control area should also be recorded. Absolute values for weed species, number of plants, and coverage. To overcome the difficulties of accurately estimating percentages and performing analysis of variance, a control efficacy survey was conducted. The following classification methods may be adopted. - Level

7.1.2 Survey Time and Frequency

7.1.2.1 The time and number of surveys of winter rapeseed fields are as follows:

a) Apply herbicide before weeds emerge. - First survey. After weeds have fully emerged in the blank control area (visual assessment, control effect); - Second survey. Before winter (number of plants counted); - Third survey. The following year, after the rapeseed resumed growth, when the weeds in the control area were growing vigorously, or when the efficacy of the experimental herbicide was at its peak. Best time (number of plants and fresh weight); - Fourth survey. Before rapeseed harvest (visual inspection, control effect).

b) Apply herbicide after weeds emerge. 1) Apply pesticides before winter. - First survey. On the day of application, or before application (measurement of weed species, density, leaf age, and growth stage, etc.); - Second survey. 2-4 weeks after application (number of plants counted); - Third survey. The following year, after the rapeseed resumed growth, when weeds in the control area grew vigorously, or when the experimental pesticides became effective... At its best (measured by number of plants and fresh weight); - Fourth survey. Before rapeseed harvest (visual inspection, control effect). 2) Applying pesticides in spring. - First survey. On the day of application, before application (measurement of weed species, density, leaf age, and growth stage, etc.); - Second survey. 2-3 weeks after application (number of plants counted); - Third survey. 4-5 weeks after application or when the experimental agent reaches its peak efficacy (counting of plants and fresh weight); - Fourth survey. Before rapeseed harvest (visual inspection, control effect).

7.1.2.2 The timing and frequency of the spring rapeseed field surveys are as follows:

a) Apply herbicide before weeds emerge. - First survey. After weeds have fully emerged in the blank control area (visual assessment, control effect); - Second survey. 2-3 weeks after weeds have fully emerged in the blank control area (number of plants counted); - Third survey. 4-6 weeks after all weeds have emerged in the blank control area, or when the experimental herbicide has reached its peak efficacy (number of plants measured). (and fresh weight) - Fourth survey. Before rapeseed harvest (visual inspection, control effect).

b) Apply herbicide after weeds emerge. - First survey. On the day of application, before application (measurement of weed species, density, leaf age, and growth stage, etc.); - Second survey. 2-3 weeks after application (number of plants counted); - Third survey. 4-5 weeks after application or when the experimental agent reaches its peak efficacy (counting of plants and fresh weight); - Fourth survey. Before rapeseed harvest (visual inspection, control effect).

7.2 Crop pesticide damage survey

7.2.1 Survey Methodology The following method can be used to visually inspect whether the pesticide has caused phytotoxicity to rapeseed.

a) Compare the herbicide-treated area with the manually weeded area to evaluate the occurrence of herbicide damage. If herbicide damage is present, record in detail the time of occurrence and... Symptoms (such as delayed emergence, reduced emergence rate, seedling death after transplanting, growth inhibition, chlorosis, yellowing, necrotic spots, deformity, leaf drying, etc.).

b) Record environmental factors (cultivation measures, soil conditions, natural disasters such as lodging, pests and diseases, harsh climatic conditions such as prolonged high temperatures and drought). The impact of drought, strong winds, hail, or freezing damage on pesticides.

c) If pesticide damage can be counted or measured, express it in absolute values and record crop emergence rate, number of damaged plants, or plant height, etc. The survey can be conducted on the entire plot or three random sampling points can be selected in each plot. At each sampling point, the number of crop plants at a height of 1m to 2m can be counted sequentially. Conduct a sampling survey.

d) In other cases, assess the extent of herbicide damage across the entire plot. Herbicide damage is graded using the following method, and the crop damage index is calculated. - Level

0.Crops are growing normally, showing no signs of damage, consistent with areas where weeding was carried out manually; - Level

1.Minor pesticide damage to crops, which can recover later and does not affect yield; - Level

2.Moderate pesticide damage to crops, recoverable later, slight impact on yield, estimated yield reduction of 1%~5%; - Level

3.Severe pesticide damage to crops, difficult to recover from, estimated yield reduction of 6%~15%; - Level

4.Severe pesticide damage to crops, irreversible, estimated yield reduction of 16%~30%; - Level

5.Severe pesticide damage to crops, irreversible, with estimated yield reduction of over 30%.

7.2.2 Survey Time and Frequency The survey period varies depending on the rapeseed cultivation type and pesticide application time; the specific number of surveys is as follows:

---First survey. In the blank control area, rapeseed seedlings had basically emerged or 2-3 weeks after pesticide application (seedling rate, whether emergence was delayed, plant height, etc.). (growth rate, similar appearance)

---Second survey. Rapeseed bolting stage (plant height, growth vigor, appearance, etc.);