Enhanced mortality of the biofouling zebra mussel, Dreissena polymorpha, through the application of combined control agents

► Reactive control of biofouling zebra mussels is improved by combined polyDADMAC/KCl. ► At high mortality levels, the biocides act more than additively on adult mussels. ► The potential of the mixture for use in proactive treatments is not as definitive. ► The biocides exert additive or less than additive effects on the veligers. ► Mixture design for pest control may be enhanced through systematic data analysis.