Contact
Menu
Home Donate Partner With Us Become a Member The Conservation Circle COL Endowment Honoraria & Memorials Preserving Land Caring for the Land Why Preserve Land? How To Protect Your Land Partnership with The Pokagon Fund Glossary of Terms Protected Properties Map Land Conservation Plan Land Stewardship Land Stewardship Volunteer Stewardship Ongoing Projects Chris Thompson Memorial Preserve Improvements Other Improvement Projects Invasive Species Visit Our Preserves COL Preserves Map Burns Prairie Preserve Chris Thompson Memorial Preserve Flynn Woods Preserve Grand Beach Marsh Preserve Jens Jensen Preserve Leonard Wildlife Preserve Galien River Marsh Preserves Merritt and Younger Family Preserves Myron Perlman Nature Preserve Robinson Woods Preserve Sugarwood Forest Preserve Turtle Creek Preserve Volunteer Stewardship Stewardship Volunteer Citizen Science Butterfly Monitoring Volunteer News & Events Latest News and Photos News Media Clips Photo Galleries COL Video Library Publications Current Newsletter Archived Newsletters Archived Annual Reports Upcoming Events Events Calendar Fall Photo Contest Enchanted Forest About About About Chikaming Open Lands Current Audited Financial Statement Board of Directors Current COL Board of Directors Staff Current COL Staff Blog Contact

Home Blog Galerucella Beetles vs. Purple Loosestrife

Galerucella Beetles vs. Purple Loosestrife

Posted on June 28, 2024

Land Protection Lesson #1: Just because something is pretty doesn’t mean it's good.
Such is the case with another “beautiful” bloom that’s beginning to put on its annual show in COL preserves: purple loosestrife (Lythrum salicaria). If you’ve ever kayaked the Galien River Marsh, visited Chris Thompson Memorial Preserve, or simply driven down Red Arrow Highway during summer, then you’ve seen (and maybe even admired) this invasive plant before. Growing anywhere from 4-10 feet tall, this plant sports spikes of bright magenta flowers, often clustered together to form broad swaths of hot pinkish-purple. Purple loosestrife is native to Asia and Europe and was introduced to North America in the 19th century, likely as an ornamental plant. Since then, it has spread rapidly, outcompeting native plants and disrupting local ecosystems.

Managing Purple Loosestrife
Like other invasive plants, purple loosestrife can be managed using manual methods, like digging or hand-pulling. However, this can be time-consuming and isn’t a viable option for large, high-density, or difficult-to-access populations. 

Chemical control is another option, but it also takes considerable time and comes with downsides. For example, while herbicide would kill the loosestrife, it could also harm beneficial plants in the process. That’s never desirable, but we especially don’t want that to happen in an area that we’ve seeded with native plants, like Chris Thompson Memorial Preserve.

Luckily, there is a third, all-natural method we use to control purple loosestrife at COL: biological control!

Welcome to the Field Crew, Galerucella Beetles
Enter the Galerucella beetles, the small but mighty warriors in this ecological drama.

These beetles were first introduced to North America in 1992 as part of a 5 to 15-year program to control purple loosestrife. The program was a success, and the beetles continue to be used as effective biological control today. We've released Galerucella beetles at COL preserves a few times now: in 2008 and 2014 in the Galien River Marsh, and in 2021 and 2024 at Chris Thompson Memorial Preserve.

How Does it Work?
Female beetles lay their eggs on the leaves of the loosestrife, and when the larvae hatch, they begin munching away. This feeding not only stunts the growth of the plants but also reduces their ability to produce seeds. Better yet, the beetles feed almost exclusively on purple loosestrife, making them an excellent tool in managing invasive species while preserving the integrity of native ecosystems. Over time, a significant population of Galerucella beetles can drastically reduce the density of purple loosestrife in an area. While the beetles aren’t likely to eradicate a population of purple loosestrife, their ability to prevent it from becoming a dominant species is worth celebrating!

Thanks, Beetles!
Galerucella beetles as biological control are an environmentally-friendly option that saves staff time and reduces the need for herbicide usage. So, next time you spot a patch of purple loosestrife, think of the valiant beetles working behind the scenes to keep nature in balance. They’re a wonderful example of how even the smallest creatures can make a big difference in protecting our natural world.