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Collaborative studies of dose‐response curves obtained with different bioassay methods for soil‐applied herbicides
Author(s) -
NYFFELER A.,
GERBER H.R.,
HURLE K.,
PESTEMER W.,
SCHMIDT R. R.
Publication year - 1982
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1982.tb00166.x
Subject(s) - metribuzin , trifluralin , transplanting , shoot , bioassay , atrazine , carbofuran , brassica , seeding , coefficient of variation , germination , horticulture , lepidium sativum , chemistry , agronomy , sowing , biology , weed control , pesticide , chromatography , genetics
Summary In a collaborative study by 12 laboratories the reproducibility of bioassay techniques was analysed by comparison and statistical treatment of the ED 50 ‐values (μg herbicide/g soil). Commonlyused bioassay techniques were investigated; two direct seeding methods, a transplanting method and a shoot extension method. The herbicides studied were two photosynthesis inhibitors, atrazine and metribuzin using Lepidium sativum and Brassica rapa as test plants; two germination inhibitors, tri‐allate and trifluralin using Avena sativa as test plant. The mean ED 50 ‐value of atrazine in the direct seeding method was 0.18 with a variation from 0.12 to 0.29 and 0.12 (0.07–0.68) in the transplanting method. The values of metribuzin were 0.05 (0.02–0.11) and 0.03 (0.01–0.15) respectively. The values for triallate were 1.15 (0.50–2.60) in the direct seeding method and 1.10 (0.54–2.53) in the shoot extension method and for trifluralin 3.11 (0.72–18.31) and 1.33 (0.48–2.94) respectively. The reproducibility was best in the shoot extension method. No outliers (confidence intervals lying entirely outside the confidence interval of the overall mean) in the ED 50 ‐values were observed with atrazine and metribuzin when using the direct seeding method, whereas with the germination inhibitors a high number of results (four with tri‐allate, six with trifluralin) could be considered as outliers. A comparison of the use of fresh weight and dry matter showed good agreement between the ED 50 ‐values they gave, with similar reproducibility.