Fluometuron-Disulfoton Interactions in Cotton as Affected by Soil Properties

Greenhouse studies were conducted to evaluate the activity of fluometuron [1,1-dimethyl-3-(α-α-α-trifluoro-m-tolyl)urea] and disulfoton [o,o-diethyls-(ethylthio ethyl) phosphorodithioate] alone and in combination on the height of seedling cotton (Gossypium hirsutumL.) in 10 light-textured soils from the lower alluvial floodplain of the Mississippi River. An antogonistic interaction was demonstrated between the two pesticides in six of the soils studied. The phytotoxic effects of high rates of fluometuron applied preemergence were decreased by granular application of disulfoton. This interaction was repeated in four of the soils and was modified but not eliminated by partial sterilization of the soils, by autoclaving, or by fumigation before treatment. Correlation analyses detected no significant association between the antagonistic interaction and any measurable soil property in the 10 soils. Three field studies failed to demonstrate this interaction. Neither the greenhouse nor the field studies revealed any deleterious interaction between these two chemicals.