Exotic Bug Released in Delta to Control Invasive Weed

Scientists with the California Department of Food and Agriculture began releasing a small insect native to South America into the Sacramento-San Joaquin Delta last month in an effort to control an invasive species of plant that has been choking waterways.

The insect, known as the water hyacinth plant hopper, has a voracious appetite for water hyacinth, an aquatic weed that has been causing serious problems in the Delta.

Water hyacinth, which itself is native to the Amazon region of South America, is a floating weed that can grow so densely that it forms thick rafts that cover the surface of the water, preventing boat access and clogging intake systems.

The leaf hoppers destroy the plant by sucking plant juices from
its leaves, eventually killing them.

Before releasing the insect, state and federal scientists reviewed it extensively to make sure its introduction into the Delta would not cause unforeseen harm to the ecosystem, said Steve Lyle, director of public affairs for the California Department of Food and Agriculture.

The creature has proven to feed only on water hyacinth, which makes it an ideal insect to use as a biological control agent, Lyle said.

He said scientists do not believe it presents any potential harm to humans or to native species living in the Delta.

So far, the department has released a little more than 5,000 water
hyacinth leaf hoppers into the Delta in Sacramento and San Joaquin counties, Lyle said.

"The hope is that we will get self-sustaining colonies," Lyle said.

If the pilot release is successful, Lyle said the department would most likely release more water hyacinth leaf hoppers into other areas in the Delta where water hyacinth is a problem.

He also said this program is one of many in which the department is working to control pests without the use of pesticide sprays.

- Bay City News