A chemically and physically stable, transparent, hybrid pesticide concentrate is provided for preparation of a water-based microemulsion formulation. The pesticides preferably comprise an oil-soluble pesticide component, and a pesticide component having a Lewis acid pesticide portion and a pesticide complex portion. An inactive biphasic coupling agent for the pesticide ingredients includes a solvent capable of solvating the oil-soluble pesticide component, and two organic cosolvents capable of solvating the Lewis acid pesticide portion and the pesticide complex portion pesticide ingredients, respectively. A selected emulsifier is incorporated in the concentrate. A sufficient quantity of a complexing agent is provided to maintain the electrical potential of the final concentrate at a value of about -150 mV to about +150 mV. The inactive coupling agent and the complexing agent are sufficient relative to the quantity of the active pesticide ingredients to cause the concentrate to spontaneously form a microemulsion made up of particles that are less than 1.mu. when the concentrate is diluted with water.