Hydrilla is a serious threat, as well as water hyacinth, and one of the biggest threats is giant salvinia. Stopping their spread is paramount. A lot more than good fishing is at stake. Billions of dollars in control costs, and a way of life are being threatened!
The spread needs to stop! We have to deal with what has already been spread, but most of the potential for continued spreading can be brought to a halt. Most of the invasion has happened with human help. A few simple precautions can stop this from continuing. Let's just call it good boating hygiene.
Where it begins.
Most new outbreaks start in areas where boats are put in to the lakes, which seems to indicate that the boats are bringing it in. The answer then, is to clean the boats properly between excursions. Check the props, live wells, bilge, everywhere from stem to stern! This might seem to be a tedious task, but it is far better than seeing your favorite fishing hole shut down! The same is true for other recreational water vehicles like jet skis.
Other areas that should be obvious: Never knowingly transport and transplant an aquatic weed, no matter how pretty you think it would look in your pond! My experience with aquatic plants seems to indicate that such behavior is responsible for the spread of water hyacinth. Water hyacinth is a very attractive plant. There is no argument about that.
The problem is that it's attractive features cause people to want to transplant it. They also are a big part of the problem. Because of it's profuse, and erratic flowering, seeding goes on for the entire growing season! If you get the urge to bring some back to your nice little pond, just remember that it can double in size and number in as little as 5 to 7 days! Without intervention, complete takeover is inevitable!
Other issues.
Other issues are such things as dumping the dead goldfish and the contents of it's bowl in a pond or lake. This is the probable source of the current hydrilla problem.
It is time to take the invasion seriously! Avoid doing the things that will cause it to spread, and when you see a suspicious weed in a pond or lake, immediate appropriate action is the order of the day!