Week of October 12, 2008

Updated 10/17

Biocontrol plans for Japanese knotweed in UK

From ExFn.com, About Science-Nature

A superweed spreading throughout the UK could be brought under control by introducing plant-eating predators from Japan, scientists believe.

Now a team of scientists has identified natural predators from its native home that could also control it in the UK.

The plans have been submitted to the government for approval.

Dick Shaw, the lead researcher on the project, from Cabi, a not-for-profit agricultural research organisation, said: “In 2000, we went out to Japan to see whether the plant had any natural enemies that it had lost when it came here.

“We found that it had a lot: there were 186 species of plant-eating insects and about 40 species of fungi.”

The team then began to test the predators to find those that only had an appetite for Japanese knotweed - and not any other plants.

Eventually, the list was whittled down to two: a sap-sucking psyllid insect (Aphalara itadori) and a leaf spot fungus from the genus Mycosphaerella.

Dr Shaw told the BBC: “We have done some efficacy trials here in the lab and they are showing a significant impact.” Article

----------------------------------------------------------

Variable-leaf milfoil found in Vermont

WATERBURY, VT – Aquatic biologists at the Agency of Natural Resources have confirmed the arrival a new invasive plant in Vermont, variable-leaved watermilfoil, in Halls Lake in Newbury.

This is the first confirmation of a new invasive aquatic plant in Vermont since European frogbit was found in Lake Champlain in the early 1990s.

The variable-leaved watermilfoil identification was confirmed by genetic analysis conducted by Dr. Ryan Thum of Grand Valley State University in Michigan.

Vegetatively, variable-leaved looks almost identical to a rare watermilfoil in Vermont. In this case, genetic identification was important as all the plants in the lake had no reproductive parts to confirm identification without this analysis.

Variable-leaved is a popular aquarium trade species and is a potential vector for invasive aquatic plant spread. The agency, in cooperation with the Agency of Agriculture, Foods and Markets, inspects Vermont aquarium retailers annually. Just recently, officials found two retailers in southern Vermont selling variable-leaved watermilfoil.

Staff at the Department of Environmental Conservation’s Water Quality Division have deployed rapid-response initiatives this week to remove the nuisance plant from the lake, which appears to be limited to a small two-acre cove at the southern end.

“We may have a rare opportunity to prevent further spread of this plant in Halls Lake and to other waters in Vermont,” said Ann Bove, an aquatic biologist at the agency. “A continued response is critical to success.”

Variable-leaved watermilfoil (Myriophyllum heterophyllum) is not native to Vermont and can be difficult to control once established. It is aggressive and grows rapidly, is easily spread by plant pieces and can displace beneficial native aquatic plants, said Bove.

Like Eurasian watermilfoil, already present in Vermont, variable-leaved watermilfoil can also make swimming, boating and other recreational uses difficult. New Hampshire, Maine, Massachusetts and New York have been plagued by this species for a number of years.

Early detection is vital to protecting Vermont’s waterbodies from harmful invasive plants and animals. The agency’s Vermont Invasive Patrollers (VIPs) program monitors local waterbodies for new introductions of invasive species while also learning about native aquatic plants and animals and their habitats. For more information on becoming a VIP, visit http://www.anr.state.vt.us/dec/waterq/lakes/htm/ans/lp_VIP.htm.

----------------------------------------------------------