An adjuvant suitable for use with a lipophilic agrochemical has the formula (I), R1-(CO)m-O-[-R2O-]n-R3, wherein R1 is a C16 to C20 straight or branched chain alkyl or alkenyl group, R2 is ethyl or isopropyl, n is from 8 to 30 and m is 0 or 1 and when R2 is ethyl, R3 is a C1 to C7 alkyl group and when R2 is isopropyl, R3 is hydrogen or a C1 to C7 alkyl group, provided that when R1 is oleyl, R2 is isopropyl and R3 is hydrogen, n is not 10. An adjuvant composition comprising an agrochemical and an adjuvant of formula (I) is also claimed. Adjuvants of the invention show effective bioperformance enhancement despite having little or no surfactant properties.