N,N'-DIBUTYLUREA FROM N-BUTYL ISOCYANATE, A DEGRADATION PRODUCT OF BENOMYL .1. FORMATION IN BENLATE FORMULATIONS AND ON PLANTS

n-Butyl isocyanate, an elimination product of benomyl, the active ingr edient in Benlate formulations, reacts with water to give the symmetri cal N,N'-dibutylurea and the salt of butylamine. Reaction is first ord er with a rate constant between 7.3 x 10(-4) and 8.4 x 10(-4) s(-1). W hen moist Boston fern and cucumber Plants are exposed to n-butyl isocy anate, N,N'-dibutylurea is formed on or in the plants' leaves. This co mpound, along with N-butylformamide and N-butylacetamide, has been fou nd in both dry flowable and wettable powder formulations of Benlate fu ngicide.