The water hyacinth plant hopper, known to scientists as Megamelus scutellaris, is approximately 1/8 inch in length as an adult.  It feeds only on water hyacinth, making it an ideal candidate for release as a biological control agent. The insects feed on water hyacinth leaves by siphoning plant juices into their mouths, much like an aphid on a rose bush.  The damage caused by their feeding kills the small area where their siphons are inserted; high densities of plant hoppers and high levels of feeding can cause whole leaves to wilt and die, reducing the infestation and relieving pressure on the waterways.

Native to the Amazon region of South America, water hyacinth has spread to more than 50 countries on five continents. It was introduced into the United States in 1884 at the Cotton States Exposition in New Orleans when display samples were distributed to visitors and extra plants were released into local waterways. By 1895, water hyacinth had spread across the Southeast and was growing in 40-km-long mats that blocked navigation in the St. Johns River in Florida. Water hyacinth was first reported in California in 1904 in a Yolo County slough.

The California Department of Boating and Waterways leads an ongoing effort to reduce the abundance of water hyacinth (Eichhornia crassipes), limit its impact on boaters and keep waterways open.  CDFA’s releases of the water hyacinth plant hopper add another tool to the state’s cooperative effort to manage water hyacinth in the Delta.

Photos of the released plant hoppers are available online at