A customer recently contacted us regarding lake weed & algae control. Below is his question and our response.
For years I have been waiting for you to include Cabomba or Carolina Fanwort in your printed catalog so I could show my fellow pond residents that particular species is recognized invasive up here in MA. I have one neighbor in particular who claims the weed has been in the pond her whole life so she thinks it belongs here. She does not accept that it is a non native species that was introduced many years ago. I need you to list that species not only in your catalog but also on your website so I can direct my neighbors to your site to prove what I have been trying to tell them for 13 years.
Fanwort, cabomba is an invasive aquatic exotic perennial that primarily spreads by stem fragmentation of rhizomes that threatens inland lakes and ponds. It can overtake native plants, have an impact on native animals and reduce recreational water activities such as boating, swimming and fishing.
Fanwort is native to South America, it is a popular aquarium plant and thought to have been brought to the U.S. through the aquarium trade.
Fanwort has intricate fan shaped leaves with white-pink floating flowers. Submersed leaves secrete a sticky mucous which covers the foliage. It is very aggressive and can rapidly force out native aquatic plants in depths up to 3 feet. Fanwort reproduces from small fragments that may survive free floating up to 8 weeks. Once the invasive species takes root it can be hard to eradicate.
Furidone is a systemic herbicide that is only effective when it is treated at 10-20 ppb.
2,4-d is a systemic herbicide that is absorbed and moves within the weed. It is used with a high degree of success. After treatment with 2,4-d, all Cabomba is killed.
Diquat, is a contact herbicide that acts quickly and will kill the foliage it touches.
When using liquid contact herbicides, thorough coverage of the weeds' foliage is necessary for good results. Inject underwater with a pressure sprayer for foliage beneath the surface. Apply on a calm, sunny day. Do not treat if rain is expected within 8 hours.
Physical removal works by hand pulling. This option works before Fanwort takes hold and only a few weeds need removal.
Drawdown works if the target area can truly be completely dried and/or frozen for at least one month. This is hard to do because muck sediments often stay moist and protect the weed root systems and allowing considerable survival.
There are no biological controls for this species.
Prevention is key, always check to make sure there aren’t plants attached to your boat or trailer before you enter or exit your lake or pond.