State College, PA - Centre County - Central Pennsylvania - Home of Penn State University

Conservationists introduce loosestrife beetles to battle invasive plants

by on June 14, 2018 9:51 AM

PORT MATILDA — A small group from Wildlife For Everyone gathered to see more than 600 alien Galerucella calmariensis beetles released late last month at the Julian Wetlands — a man-made marsh adjacent to Miles Hollow Road, north of Port Matilda.

Insects accidently imported from other countries have caused big problems. The list is long — emerald ash borer, gypsy moth, hemlock wooly adelgid and, now, the spotted lanternfly. However, this alien beetle has been introduced to solve a problem, not cause one.

The Julian Wetlands was donated to the State College-based Wildlife for Everyone Foundation by the WHM Group in 2010. This mitigation wetlands property is an important stopover for migrating waterfowl and the home to many species, including wood ducks, bluebirds, yellow warblers and Virginia rails.

During the past few years, purple loosestrife, a pretty but invasive wildflower, has shown up at the wetlands. Purple loosestrife was introduced to North America in the early 1800s, and is now found across most of the entire United States, except the arid Southwest, and much of Canada.

Although it has beauty, loosestrife is an unwanted non-native species. Each plant can produce thousands of seeds a year, and the dense masses of stems make the wetland unattractive to waterfowl. It grows from 3 to 10 feet high and is adaptable to many types of wet soils.
“Purple loosestrife is an invasive species that can entirely choke out the native plant community in a wetland and destroy the functions and benefits of that ecosystem," said Colleen DeLong, habitat steward biologist for ClearWater Conservancy.

"Our Wildlife For Everyone wetlands property has some wonderful biodiversity and we want to continue enhancing the habitat as a wildlife foundation," said Jerry Regan, president of Wildlfe For Everyone. "If left unchecked, the nonnative loosestrife would destroy the wetland. We elected to step out of the box and use a biological control to help us solve the problem, rather than chemicals."

Galerucella calmariensis, better known as the loosestrife leaf beetle, is one of two species of beetles used to control the invasive loosestrife. According to WHM wetlands scientist Peter Backhaus, who supervised the May 23 beetle release, both beetles were studied extensively and found to be safe. They provide a better alternative than chemicals or manual extraction.

"The loosestrife leaf beetle, a native of Eurasia, has been released in at least 27 states and in Canada with no adverse affects," Backhaus said. Here in Centre County, the loosestrife eating beetles have been used at three places — Millbrook Marsh, Muddy Paws Marsh and now at the Julian Wetland.

However, the beetles are expensive. According to Backhaus, more than 600 of them were shipped overnight from Montana and released at Julian Wetlands, costing about $1.25 each.

"A few years ago, you could buy the beetles fairly cheaply, but there are fewer growers now and they are quite expensive," said Backhaus.

The beetles — housed approximately 105 per container — were released at three pre-selected locations on the wetland. Almost immediately, they started eating loosestrife and mating.

"They will reproduce several times this summer, and there should be thousands eating the loosestrife by the end of summer," said Backhaus. 

According to Penn State University wetlands ecologist Robert Brooks, two species of loosestrife-eating beetles — the leaf beetle and the golden loosestrife beetle — were released at Millbrook Marsh about 15 years ago. This was after other methods of control proved to be ineffective.

"We had tried mechanical removal, pulling up or breaking off the plants the year before, and that just stimulated purple loosestrife growth. Since introducing the beetles, the loosestrife density was decreased, with just a few plants remaining," Brooks said. "With the help of the beetles, we were able to knock back the loosestrife right away, and, now, over 15 years later, purple loosestrife is still only a small part of the plant community instead of taking over the wetland and fen habitats.”

About 6,000 of the two same beetle species were released at Muddy Paws Marsh near Spring Mills in 2007. At that time, the wetland was choked with loosestrife, and in the summer, it was a sea of pinkish-purple blossoms.

"We had a lot of loosestrife," said Mary Kay Williams, co-owner of Muddy Paws Marsh. "Our beetle release was a partnership funded through a Growing Greener grant obtained by the Penns Valley Conservation Association, and the beetles were purchased and released by the U.S. Fish and Wildlife Service.

"We noticed the first significant damage to the loosestrife in 2008, and by 2010, the beetles were really controlling the invasive loosestrife," said Williams. "By 2012, I thought that we were done with loosestrife forever, but late last summer, it reared its ugly head again and came back with a vengeance."

Williams thinks that the loosestrife beetles from Muddy Paws might have moved to another nearby wetland that had more loosestrife. If so, Muddy Paws will likely need a new introduction of these insects.

Back at Julian Wetlands, the project is off to a good start. Backhaus has visited the sites twice since the beetles were released, and he is documenting what he and Wildlife For Everyone hopes is the progress of the loosestrife control. His most recent inspection was June 7. While he did not see any beetles, holes in the plant's leaves were quite extensive around the release sites and some browning leaves could be seen.

Regan said he is pleased with the effort. "So, it seems that our experiment is working and those little beetles are doing their job eating away."


Disclaimer: Copyright © 2019 All rights reserved. This material may not be published, broadcast, rewritten or redistributed.