ABSTRACT
Polysorbate surfactant (hydrophile-lipophile balance [HLB] 4.3) eroded cotton (Gossypium hirsutum L.) leaf surfaces severely at 1% (w/w) concentration, as shown by scanning electron photomicrography. Reticulated and etched patterns were observed on cotton leaf surfaces treated with water-soluble surfactants. Trichomes on the leaves of prickly sida (Sida spinosa L.) did not appear to be affected by the surfactants. Leaves of prickly sida were less affected than those of cotton. The surface deposits of formulated methazole were different in appearance from those of technical methazole. The 14C-methazole and/or its 14C-labeled metabolites moved acropetally in the treated leaves of cotton and prickly sida. This pattern was not altered with polysorbate surfactants with different HLB values. Total uptake and distribution of 14C increased with increasing concentration of methazole and decreasing HLB values of surfactants. More 14C was translocated in cotton than in prickly sida. The effects of surfactants were masked by the drastic solvent action of 100% methanol. When the solvent effect was subtracted, the surfactant with HLB 8 caused the greatest enhancement of translocation in both species. Radiolabeled methazole leached poorly in a silt loam soil and was either slightly retarded or unaffected by added surfactants. The influence of HLB of polysorbate surfactants on 14C-methazole mobility was minimal.
