Table 1.

Parameters of the log-logistic equations^a used to calculate the glyphosate rates (g ae ha⁻¹) required for 50% reduction in dry weight (GR₅₀) or survival (LD₅₀) of C. canadensis and L. rigidum populations.

GR50
Species	Treatment	b	d	GR50 (g ae ha−1)	P-value	IE
C. canadensis	Glyphosate	1.56	100.88	95.86 ± 5.98	<0.001	-
	Glyphosate + Adj	0.96	98.99	72.64 ± 6.99	<0.001	24.22
L. rigidum	Glyphosate	0.99	100.99	36.56 ± 3.99	<0.001	-
	Glyphosate + Adj	1.03	98.86	28.18 ± 3.32	<0.001	22.92
LD50
Species	Treatment	b	d	LD50 (g ae ha−1)	P-value	IE
C. canadensis	Glyphosate	2.81	96.38	493.89±16.52	<0.001	-
	Glyphosate + Adj	2.38	101.68	283.06±18.22	<0.001	42.52
L. rigidum	Glyphosate	3.45	100.56	468.98±23.87	<0.001	-
	Glyphosate + Adj	2.69	100.99	275.88±17.06	<0.001	41.17

^a Y = [(d)/1 +(x/g)^b] where: d is the coefficient corresponding to the upper asymptote, b is the slope of the line, x the herbicide dose, and g is the dose at inflection point, hence the GR₅₀ or LD₅₀. IE (Increase effectiveness) = The increase in the effectiveness of Adj [(GR₅₀ gly-GR₅₀ gly + adj)/(GR₅₀ gly)]*100 or [(LD₅₀ gly-LD₅₀ gly + adj)/(LD₅₀ gly)*100].