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Quantitative bioassays for determining residues and availability to plants of sulphonylurea herbicides
Author(s) -
GÜNTHER P.,
RAHMAN A.,
PESTEMER W.
Publication year - 1989
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.1365-3180.1989.tb00852.x
Subject(s) - vermiculite , bioassay , soil water , chemistry , loam , 2,4 dichlorophenol , horticulture , botany , biology , environmental science , soil science , bacteria , genetics
Summary A bioassay procedure for quantitative determination of sulphonylurea herbicides is described. Turnips ( Brassica rapa ) were found very suitable as test plants and gave results within 10 days. Six sulphonylurea compounds were investigated for their activity in three widely differing soils. The potential availability to plants was calculated from the dose‐response curves of vermiculite (non‐sorptive substrate) and the corresponding ED 50 ‐values of the soils. The dose‐response relationship (logistic curve) was described by a computer model by a position parameter, the slope of the curve and the minimum and maximum fresh weights of plants. The limit of quantitative detection in the range of ED 30 in vermiculite was 0·06 μg 1 −1 for sulfometuron and 1·03 μg 1 −1 for DPX‐L5300, methy12‐([4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl (methyl)carbamoyl]‐sulphamoyl) benzoate. Results with turnips showed that sulfometuron was the most active compound in all substrates (ED 50 in vermiculite 0·12 μg 1 −1 ) followed by chlorsulfuron, metsulfuron‐methyl, triasulfuron, DPX‐M6316, methyl 3‐([(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)aminocarbamoyl]‐aminosulphaphamoyl)‐2‐thiophenecarboxylate, and DPX‐L5300 which had ED 50 or 1·98 μg 1 −1 , The Horotiu sandy loam soil showed the highest ED 50 ‐values and the lowest plant availability for all compounds compared to the other soils. Probit and logistic evaluation methods for deriving dose‐response relationships are compared and their applicability is discussed.