Loosestrife Menace to Local Pond Combated With Bio-control

Undergrads engage in research at Lums Pond

Until recently, the Del Bay Retriever Club (DBRC) gathered at Flat Pond, a favorite area to train and exercise their dogs at Lums Pond State Park . Then purple loosestrife, an invasive plant, took over the natural vegetation in the pond, severely hindering the club's activities. Not only was mobility around the pond increasingly limited, members could not follow their dogs through the thick growth, nor could the dogs see well enough to respond to hand commands.

Purple loosestrife ( Lythrum salicaria ), introduced into the United States in the 1800s as an ornamental plant for gardens, is now clogging marshes and wet ditches throughout the country, according to Susan Barton, UD Cooperative Extension horticulture specialist. "This nuisance plant, which can reach heights of 8 feet, invades nearly any wet habitat, displacing native plants and upsetting the ecological balance. Its seeds are widely distributed, carried by wind and water, and each plant can produce 3 million seeds a summer."

Hopeful for a solution to the loosestrife problem, retriever club member Ken Eckhardt, a retired University of Delaware sociology professor, learned about the resources on environmental research available at the College of Agriculture and Natural Resources (CANR). He enlisted the help of Dr. Judy Hough-Goldstein, a professor in the department of entomology and wildlife ecology. She viewed the Lums Pond challenge not only as an opportunity to test a beetle as a bio-control-an environmentally friendly insect-against purple loosestrife, but also as a way to engage two undergraduates in real-world research, which was funded through the Delaware Water Resource Center and the UD Science and Engineering Scholars program.

The study combined aspects of water quality, ecological balance, entomology and plant science with far-reaching potential. An environmentally friendly solution was needed to rid the pond of purple loosestrife without affecting surrounding native vegetation. Bio-control is a more lengthy option than using herbicides, it is worth the wait, says Hough-Goldstein, since the beetles pose no threat to the surrounding environment or DBRC members and their dogs.

Summer interns Jason Graham, an entomology major, and wildlife conservation major Jamie Pool worked with Hough-Goldstein in her plan to use beetles that thrive on a menu of purple loosestrife. In June 2004, Graham and Pool released 5,000 Galerucella calmariensis and pusilla beetles at the Flat Pond site. These two beetles look similar and have comparable life cycles and behavior. N ative to Europe and Asia, where purple loosestrife originated, the beetles usually are reared and released together. A lengthy study on their impact and host specificity was conducted before they were released in the United States.

"Beetles are bought from a beneficial Insect rearing laboratory, selling for $100 per 1,000 beetles," Hough-Goldstein says. "Of course, the more you release, the more quickly you can get some measure of control, so we will want to release as many as we can."

Throughout summer, the undergraduate researchers monitored the behavior of the beetles and their progress in controlling purple loosestrife. The beetles have established a thriving colony at Flat Pond, and the level of damage to the invasive plant around the area of release was significant. In some areas, where the beetles have been released, purple loosestrife has virtually disappeared. When the beetles were finished devouring the plant's mature stems, they entered diapause-or hibernation-until spring of 2005, when two new interns will pick up the study where Graham and Pool left off.

Graham and Pool gained valuable field experience for wherever their careers may led. "I had experience working with plants and insects doing lab work at the USDA Beneficial Insects Research Center here on campus," says Graham, a sophomore studying entomology and wildlife ecology. " In addition to the challenge of the research, I learned something about myself-I like field work. I learned what it takes to put an experiment together and monitor for success. It's a good feeling."

Pool agrees with his co-researcher. "My research experience had been confined to a microscope in the laboratory. This field study opportunity provided me invaluable knowledge," he says. "Jason and I were given relative autonomy in developing how the study would be carried out, so we were accountable, which was both daunting and exhilarating."

The National Fish & Wildlife Foundation (NFWF) recently announced through its Chesapeake Bay Small Watershed Grants Program a grant to the Del Bay Retriever Club to continue the beneficial insects project for controlling purple loosestrife.

"The NFWF has funded a larger-scale effort to control purple loosestrife as part of it's effort to assist local groups reclaim and improve the environment for the benefit of native plants, wildlife and water enhancement," Eckhardt explains. "Some of the grant funds will probably be used to support a student to continue the research next spring and for purchase of 10,000 purple loosestrife-eating beetles.

"With Dr. Hough-Goldstein's leadership on this project, we had a successful pilot study and are looking forward to success in 2005," Eckhardt says.