The invention is an emulsifier adjuvant system for forming a substantially solventless or solvent free emulsifiable pesticidal composition. The emulsifier system comprises from about 25 to about 80% by weight, of surfactants in the emulsifier system, of at least one anionic surfactant having an average HLB value of from about 6 to about 11 and from about 20 to about 75% by weight of surfactants in the emulsifier system of at least one nonionic surfactant having an average HLB value of from about 11 to about 18.The emulsifier and adjuvant system of the invention can form emulsifier concentrates of solventless pesticidal compositions with a concentration of the pesticidal composition up to about 90% by weight.