DNREC will begin the annual treatment of downstate public ponds – Wagamons Pond in Milton and Concord Pond near Seaford – for the foreign invasive aquatic weed hydrilla on Thursday, June 13, weather permitting. Hydrilla is a non-native plant that likely entered the state through the aquarium trade. Uncontrolled hydrilla can choke ponds and other waterways, crowding out beneficial plant species and preventing fishing and boating access.