Effect of a Nalco-Trol® II on bioavailability of glyphosate in laboratory trials

Abstract

Abstract The effect of a polymeric adjuvant “Nalco‐Trol® II” on bioavailability of glyphosate (in Roundup® formulation), was studied using trembling aspen, Populus tremuloids Michx., seedlings. Absorption and translocation of 14C‐labeled glyphosate was determined with and without Nalco‐Trol II, after application at a dosage rate of 0.35 kg of active ingredient (AI) in 25 L of aqueous solution per ha surface area of leaves. At 48 h after treatment, less than 40% of the applied amount was absorbed and translocated into the plants, and more than 60% was washed away from the treated leaves. Toxic effects of glyphosate (nonlabeled) were assessed for a period up to 28 d after treatment using three parameters, viz., changes in plant height and weight (during 28 d) and chlorophyll content of untreated leaves (during 15 d). The glyphosate‐treated plants showed little increase in height, compared to the control plants, but showed significant reduction in weight and in leaf chlorophyll. No significant differences we...