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Beetles cause strife to weeds

Beetles are slowly eating their way through the purple loosestrife population growing in a wetland behind the Greenbank Farm. - Photos courtesy of Jennifer Andreas
Beetles are slowly eating their way through the purple loosestrife population growing in a wetland behind the Greenbank Farm.
— image credit: Photos courtesy of Jennifer Andreas

After volunteer efforts by humans failed to remove an invasive weed from a wetland near the Greenbank Farm, bugs were brought in to solve the problem.

For the past several years, beetles have gradually been chewing away at the pesky purple loosestrife that has taken over the wetland area.

Mark Fessler, a volunteer working to eradicate the weed problem, said that the amount of loosestrife growing in the wetland was reduced between 30 and 40 percent in 2007.

Fessler said the plant can change the water chemistry of a wetland and that change is hard on wildlife habitat.

Volunteers from the Washington Native Plant Society initially tried to remove loosestrife by hand. In 2005 they donned hip boots and waded out into the swamp to clip the seed heads. They filled three pickup loads with the heads, but they weren’t able to stem the spread of the invasive weed.

Seeing the futility of that course, Fessler said volunteers searched for different solution. The WSU Extension King County had the answer.

As part of its integrated weed control project for Western Washington, the King County group had access to Galerucella beetles, which basically defoliate and skeletonizes the plants.

“The whole intent is not to disturb the wetland,” Fessler said.

Jennifer Andreas, integrated weed control project lead for WSU Extension King County, said the beetles were successful in removing weeds in Eastern Washington near Ephrata.

The positive part of using bugs, is it eventually reduces the plant population without disturbing the area. As the number of purple loosestrife plants diminishes, it allows native plants to creep in, Andreas said.

While the bugs have been effective in helping remove unwanted weeds, it has taken several years for them to show their effectiveness at the Greenbank Farm.

“We’re pleased with how it’s looking, but it does take time,” Andreas said.

She said the bugs are tested in quarantine conditions to determine how effective they will be in removing invasive plants. Once their job is complete, they die out.

The purple loosestrife originates in Europe. Its seeds came over in the ballast of ships. At first gardeners thought the plant was pretty and it cropped up in their gardens, causing it to spread.

The beetles aren’t the only bugs that can be used used to remove purple loosestrife from the Greenbank Farm. Reinforcements are being called in.

Andreas said a flower bud weevil will be introduced to the wetland in August. These creatures plant larvae within individual flowers of the weed, which prevents them from producing seeds.

In addition, there are plans to introduce a root weevil in the future to attack the plant’s roots. Andreas said such weevils are difficult to find and they won’t be placed in the wetland until next year.

She said that will help destroy the plant by attacking it at different spots. Hopefully those weevils will get to the root of the problem in the wetland at the Greenbank Farm and stamp out loosestrife permanently.

After volunteer efforts by humans failed to remove an invasive weed from a wetland near the Greenbank Farm, bugs were brought in to solve the problem.

For the past several years, beetles have gradually been chewing away at the pesky purple loosestrife that has taken over the wetland area.

Mark Fessler, a volunteer working to eradicate the weed problem, said that the amount of loosestrife growing in the wetland was reduced between 30 and 40 percent in 2007.

Fessler said the plant can change the water chemistry of a wetland and that change is hard on wildlife habitat.

Volunteers from the Washington Native Plant Society initially tried to remove loosestrife by hand. In 2005 they donned hip boots and waded out into the swamp to clip the seed heads. They filled three pickup loads with the heads, but they weren’t able to stem the spread of the invasive weed.

Seeing the futility of that course, Fessler said volunteers searched for different solution. The WSU Extension King County had the answer.

As part of its integrated weed control project for Western Washington, the King County group had access to Galerucella beetles, which basically defoliate and skeletonizes the plants.

“The whole intent is not to disturb the wetland,” Fessler said.

Jennifer Andreas, integrated weed control project lead for WSU Extension King County, said the beetles were successful in removing weeds in Eastern Washington near Ephrata.

The positive part of using bugs, is it eventually reduces the plant population without disturbing the area. As the number of purple loosestrife plants diminishes, it allows native plants to creep in, Andreas said.

While the bugs have been effective in helping remove unwanted weeds, it has taken several years for them to show their effectiveness at the Greenbank Farm.

“We’re pleased with how it’s looking, but it does take time,” Andreas said.

She said the bugs are tested in quarantine conditions to determine how effective they will be in removing invasive plants. Once their job is complete, they die out.

The purple loosestrife originates in Europe. Its seeds came over in the ballast of ships. At first gardeners thought the plant was pretty and it cropped up in their gardens, causing it to spread.

The beetles aren’t the only bugs that can be used used to remove purple loosestrife from the Greenbank Farm. Reinforcements are being called in.

Andreas said a flower bud weevil will be introduced to the wetland in August. These creatures plant larvae within individual flowers of the weed, which prevents them from producing seeds.

In addition, there are plans to introduce a root weevil in the future to attack the plant’s roots. Andreas said such weevils are difficult to find and they won’t be placed in the wetland until next year.

She said that will help destroy the plant by attacking it at different spots. Hopefully those weevils will get to the root of the problem in the wetland at the Greenbank Farm and stamp out loosestrife permanently.

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