Hooking up became substantially more difficult for gypsy moths in three tracts of northeast Iowa timber Monday following the aerial spraying of pheromone flakes.The flakes confound male gypsy moths, which are attracted to their mates by the powerful scent released by the flightless female moths.“The males get off track and can’t find the females, which disrupts natural reproduction,” said Mike Kintner, gypsy moth and emerald ash borer coordinator for the Iowa Department of Agriculture and Land Stewardship.Low flying airplanes released the flakes Monday in wooded areas of Allamakee and Jackson counties to slow the spread of gypsy moths, a pest that can destroy trees and shrubs.The treatment covered 13,520 acres in three blocs, all on the leading edge of gypsy moth expansion.