Only the dioecious biotype is found in Florida, although monoecious hydrilla has been reported as far south as Macon, Georgia. The following excerpt is taken from the Florida Aquatic Plant Survey Report 1992 . Since 1984, hydrilla has been the most abundant aquatic plant found in Florida public waters. The percentage of waters infested by this invasive exotic plant has increased from 37 percent to 41 percent during the period 1983 to 1992. Plant acreage has expanded by a net 10,000 acres over the past 10 years.
Waters continue to be infested providing new examples of hydrilla's tremendous growth rate.
The latest lesson is being learned on Lake Weohyakapka. Hydrilla was discovered in Lake Weohyakapka in 1991, but too late to contain it at the boat ramp. At its current rate of expansion, it is expected to fill this 7,500 lake by late 1993. Approximately 2.5 million dollars per year is spent on dioecious hydrilla control in South Carolina. State officials estimate that there are 50,000 hydrilla infested acres statewide and the infestation areas are still expanding.