ISDA takes the helm in milfoil fight

SANDPOINT — The Idaho State Department of Agriculture will be taking point in this summer’s battle against Eurasian milfoil.

Bonner County’s ISDA-funded control efforts have led to significant reductions in the distribution and densities of the pernicious aquatic weed, but the infestations in Pend Oreille and Priest lakes have proven to be the most challenging to treat, said ISDA spokeswoman Pamela Juker.

Juker said the challenges involve water exchange, depth, drinking water use and re-infestation from upstream sources.

“To maximize the efficacy and efficiency of milfoil treatment efforts, ISDA will be taking a more active role in milfoil projects to implement a more directed and focused program due to the complex nature of the treatments to the remaining milfoil populations,” Juker said in an e-mail to The Daily Bee.

The county and its Aquatic Invasive Species Task Force will collaborate with this summer’s programs.

The state’s control programs in Bonner County will be discussed during a public meeting on Thursday, June 24. It starts at 5:30 p.m. in the Bonner County Administration Building.

The meeting will also cover boat inspection stations and the Idaho Aquatic Invasive Species Prevention Program, in addition to several research projects planned for this summer.

The U.S. Army Corps of Engineers has awarded ISDA funding to tackle flowering rush infestations with herbicides and bottom barriers.

Kate Wilson, who chairs the county task force, said the flowering rush infestation at the Clark Fork Driftyard has expanded and the weed is spreading.

“This last season, we found it pretty far up Boyer Slough out in Kootenai Bay,” said Wilson, adding that isolated infestations have turned up in Dover and Laclede.

The corps is also funding a dye study by resource management firm Tetra Tech, herbicide manufacturer SePRO and application contractor AquaTechnex.

“The objective of this particular project is to address some of the water exchange in the deep-water sites for milfoil,” Wilson said.

Wilson said dye and herbicide will be applied in a number of sites to assess contact times and exchange rates.

The corps has also added funding to a locally-developed project to determine the effectiveness of weevils on milfoil infestations, Wilson said. Over the Montana border, Sanders County received funding for herbicide applications and bottom barriers.

Wilson anticipates this summer’s general control efforts will be concentrated in the latter part of the summer.

“You can’t do the treatments until you do a survey, and we can’t survey if the plants aren’t big enough to find. It sounds like we wouldn’t even do the survey until August,” she said.