Scientists Release Biocontrol for Water Hyacinth

ScienceDaily (May 18, 2010) — A new insect that will help control the invasive weed waterhyacinth has been released by Agricultural Research Service (ARS) scientists and cooperators.

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Waterhyacinth (Eichhornia crassipes) is a free-floating aquatic plant native to South America that has infested freshwater ecosystems from North Carolina to California but is especially problematic in the southeastern United States. The plant is a real menace, affecting water traffic, water quality, infrastructure for pumping and hydroelectric operations, water use and biodiversity. Other problems include fish kills due to low oxygen levels and increases in populations of vectors of human and animal diseases.

ARS entomologists Philip Tipping and Ted Center, both with the agency's Invasive Plant Research Laboratory (IPRL) in Ft. Lauderdale, Fla., worked closely with scientists at the ARS South American Biological Control Laboratory (SABCL) in Buenos Aires, Argentina, to find and test Megamelus scutellaris, a new biocontrol for waterhyacinth.

M. scutellaris is a small planthopper native to South America whose nymphs and adults feed on the sap of waterhyacinth. Nymphs are active and readily hop, even off the surface of the water. The insect's population increases rapidly, which will enable it to quickly impact the waterhyacinth population.

Herbicides are the primary method for reducing waterhyacinth, but their use directly interferes with the biocontrol agents currently deployed against this weed. The scientists believe M. scutellaris may integrate better with existing herbicide programs because of its mobility, which should improve its survival in such highly managed systems.

The researchers collected adults of M. scutellaris from Argentina in April 2006 and brought them to the quarantine facility in Ft. Lauderdale where extensive host-range studies were conducted. They found that the planthopper is highly host-specific and does not pose a threat to native or economically important species.

Tipping and Center joined representatives from the Florida Fish and Wildlife Conservation Commission, which provided more than $300,000 in financial support for the project, and the U.S. Army Corps of Engineers at an event celebrating the insect's release at the Edgefield Regional Stormwater Treatment Facility owned by the St. Johns River Water Management District near Palatka, Fla.

Invasive species discovered in Dutchman Lake

BY THE SOUTHERN

HARRISBURG -- A kayaking trip on Dutchman Lake in early September, 2008, turned into an adventure in early detection and rapid response for Melissa Mead, Student Career Employment Program ecologist for the Shawnee National Forest, when she collected water hyacinth (Eichhornia crassipes), an invasive aquatic plant species, for the first time on the forest.

Mead collected and pressed the unknown plant for later identification in her Wetland Ecology Course at Southern Illinois University at Carbondale. Melissa reported the site to Susan Corey, botanist/ecologist in the Mississippi Bluffs Ranger District and, together, on a cold November day, they removed all of the visible plants from the lake. A total of 14 large trash bags and an estimated 700 pounds of soggy plants were removed.

While removing the water hyacinth, the two discovered the presence of another invasive aquatic plant species, parrot feather watermilfoil (Myriophyllum aquaticum), and also removed it. This was the first documentation of the parrot feather watermilfoil on the Shawnee National Forest.

The collaborative effort between the Shawnee National Forest and the River-to-River Cooperative Weed Management Area (CWMA) developed over the past couple of years has been highly beneficial, not only to the forest, but to all of Southern Illinois.

During the summer of 2008, Chris Evans, coordinator for the CWMA, organized aquatic invasive plant surveys at all boat ramps on impoundments in Southern Illinois. Mead and two seasonal Student Temporary Employment Program employees in the Mississippi Bluffs Ranger District were involved in conducting these surveys on national forest lands.

“This is a great example of effective early detection and rapid response within an agency: find a new plant, identify it as a problem, contact the appropriate persons within the agency, rapidly respond to neutralize the threat and develop a plan to continue monitoring the site to ensure the population remains controlled,” Evans said.

Resources on water hyacinth

A workshop on water hyacinth (Eichhornia crassipes) was held June 2-4, 2008 in Spain. Hosted by EPPO and the Council for Europe, powerpoint presentations from the meeting can now be viewed online.


Photo courtesy of Ted D. Center, USDA ARS, www.invasive.org