ABSTRACT
Herbicide applications with which an adjuvant is not included in the spray solution are rare. One or more adjuvants may be included in the herbicide formulation and additional adjuvants may be included in the herbicide formulation and additional adjuvants may be added to the spray mixture by the farmer. Hydrophobic-lipophobic-balance (HLB) numbers are an index used to suggest the applicability of surfactants as emulsifiers, detergents, and, increasingly, as activator adjuvants. The HLB system was originally introduced by Griffin in the late 1940s as an aid in emulsifier selection. Until the mid 1970s, the principal activator adjuvants used in conjunction with herbicides were surfactants. Since that time, blends of phytobland oils and surfactant have become increasingly popular as adjuvants with herbicides applied postemergence. Many physiological activities are disturbed by surfactants, including inhibition of nucleic acid and protein synthesis and, in a few examples, either increased or decreased enzyme activity.
