Leaf Beetles Battle Weeds

Millions of leaf beetles are gnawing their way through purple loosestrife at Oregon’s Baskett Slough National Wildlife Refuge, putting the noxious weed in its place.

The beetle, however, is doing so well it could threaten domestic crops, so scientists are collecting and packaging them for shipment to other refuges in Oregon, Washington and Idaho.

“Our population of beetles here has just exploded,” said Eric Coombs, a biological control entomologist with the Oregon Department of Agriculture.

Nearby, loosestrife plants stood full of beetle bites. Instead of blooming with purple glory, most were withered, dying or dead.

Loosestrife came to the United States a century ago and was sold as an ornamental plant. Retail sale was banned after scientists discovered the hazards.

When the European plant arrived at the Baskett Slough several years ago it quickly covered much of the lake’s edges, forcing out native plants and gobbling up habitat for native birds and other wildlife.

If left alone, the weed can take over entire wetland areas, upsetting the food chain.

“This was a sea of purple last year,” Coombs said, waving his arms across the refuge’s Morgan Lake.

Five years after scientists introduced two types of beetles, along with root weevils and seed weevils, the weed has been hammered.

The habitat proved ideal for the beetles, in part because Morgan Lake’s water level is artificially controlled, diminishing flooding that can harm the beetle.

Coombs said weed-eating bugs often take 10 to 15 years to develop viable populations.

The use of beetles to fight loosestrife grew out of years of research, costing about $1 million. Scientists studied the beetles’ and weevils’ eating habits before gathering the bugs from Germany and releasing them here.

, DataTimes