War on Weeds: Brazilian elodea


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This weed may invade your land. Be ready to oppose it.

The Enemy: Brazilian elodea (or egeria or ancharis) (Egeria densa)

Strategy: This is a perennial aquatic broadleaf weed that inhabits numerous waterways throughout the United States. This plant was added to the noxious weed list in Idaho due to its ability to destroy lakes and rivers by outcompeting native habitat and by growing so thick that it destroys fish and recreation opportunities. The plant has four spiny leaves to a whorl that occur on all sides of the stem. It produces white flowers that will bloom above the water surface.

Attack: Because this plant can spread by fragmentation, it can move from water system to water system on boats or trailers. Once established, it roots into the soil below the water line and creates large mats of weeds that can stop boats and kill fish. The plant is usually introduced by someone dumping their aquarium tank into the water in hopes of their pet fish surviving in the wild. Not only does this introduce non-native fish, but it also contaminates the water body with weeds. Since most plant are males, the primary methods of spreading is by fragmentation.

Defense: Prevention — make sure your boats, trailers, and other water toys are clean of any debris before moving away from the dock areas. Hand harvesting has been known to be effective, although extremely expensive. There are a few herbicides that the EPA have designated as safe to use in these water systems and are very effective in destroying the concentrations of the weeds. Products such as Navigate, Reward or even Sonar are the ones used to control the weed. Help us out by checking your aquarium and supply stores in ensuring that we are all doing out part to protect our natural resources. Clean, drain and dry all your equipment.

To learn more, call Bonneville County Weed Superintendent Jeffrey Pettingill at 208-529-1397 or email weeds@co.bonneville.id.us.