Warecare environmental scientist Chris Garton has come up with an ingenious way of killing midges at the wastewater treatment plant in Māngere, south Auckland, Stuff reports. The rig involves a jetski dragging what looks like chains with spikes, but it’s a world-first device designed for the single purpose of killing midge fly larvae. It also means Watercare can ditch importing the expensive methoprene which cost it $300,000 a year. Garton’s method only costs $75,000.