Table III. Foliar activity of malathion plus either mesotrione or atrazine applied to MCR waterhemp populations.

MCR waterhemp seedlings (10–12 cm tall) were treated with malathion at 2,000 g ai ha⁻¹, including 0.25% (v/v) nonionic surfactant as an adjuvant, 1 h before a postemergence application of either mesotrione (105 g ai ha⁻¹) with 1% (v/v) COC and 2.5% liquid ammonium sulfate (v/v) as adjuvants or atrazine (1,681 g ai ha⁻¹) with 1% (v/v) COC as the adjuvant, followed by a soil drench of 5 mm malathion solution (50 mL pot⁻¹). The comparison of the mixture of malathion plus each herbicide with the herbicide tested alone was analyzed by ANOVA using PROC MIXED in SAS Release 9.2.

Treatment	Mean Biomass	Percentage of Control	Difference	P	Conclusion
	g		g
Control (experiments. 1, 2, and 3)	3.28
Malathion	2.83	86
Mesotrione	1.65	50
Malathion + mesotrione	1.16	35	−0.49	0.118	Moderate evidence of increased efficacy
Control (experiments 1 and 2)	3.64
Malathion	3.04	83
Atrazine	3.01	83
Malathion + atrazine	2.47	68	−0.54	0.160	No evidence of increased efficacy