Purple Loosestrife Project Biocontrol Sites:

Purple Loosestrife Project Biocontrol Sites: Interim results of a cooperative project between Michigan State University and Michigan Sea Grant Extension Photos, Maps and Layout by Jason K. Potter 2002

Purple Loosestrife Project Biocontrol Sites: Interim results of a cooperative project between Michigan State University and Michigan Sea Grant Extension

Purple Loosestrife Biological Control Site Release Dates 1994-1999

Crow Island Purple Loosestrife Biological Control Site Roadside (PL01) - Saginaw County, MI. - August 5, 2002 West The site at Crow Island near Saginaw was first inoculated by DNR with 875 adults in 1994. This site was heavily infested on release. While loosestrife persists, in 2002 only a few flowering plants could be found. They are significantly shorter than normal and show heavy insect damage.

Crow Island Purple Loosestrife Biological Control Site PL02 - Saginaw County, MI. - August 19, 2002 West The second Crow Island release site is in a large wet meadow that in 1994 was completely covered with loosestrife plants more than 1 meter tall. At present, the only visible loosestrife plants average about 25 cm in height and are nearly completely defoliated.

Nayanquing Point Purple Loosestrife Biological Control Site Meadow (PL03) - Saginaw County, MI. - August 5, 2002 West In 1994 the DNR released 875 adult Galerucella beetles in a wet meadow next to a drainage ditch in the Nayanquing Point Game Area in Saginaw County. At the time of release, purple loosestrife coverage was about 30%. By 2000, coverage had decreased to 3%. In 2002, as shown in these images, loosestrife plants were scattered and showed significant insect damage.

Nayanquing Point Purple Loosestrife Biological Control Site Impoundment (PL04) - Saginaw County, MI. - August 5, 2002 West In 1994 the DNR released 875 adult Galerucella beetles in a wet meadow next to a drainage ditch in the Nayanquing Point Game Area in Saginaw County. At the time of release, purple loosestrife coverage was about 30%. By 2000, coverage had decreased to 3%. In 2002, as shown in these images, loosestrife plants were scattered and showed significant insect damage.

Shiawassee River SGA Purple Loosestrife Biological Control Site (PL05) - Saginaw County, MI. - August 6, 2002 West The Shiawassee River State Game Area Contains a mixture of loosestrife infested impoundments and riparian areas. In 1994, 1750 adult Galerucella beetles were released into this 640 acre impounded marsh. About 50% of the impoundment was dominated by loosestrife and by 1995, the insects were firmly established. This site has been interesting for the way that the insects suppressed the plants, followed by regrowth of plants, followed by another wave of damage. In the image, areas of suppression and regrowth are both visible. View to South showing reduction of loosestrife where beetles were released compared to un-infested area in background.

Lost Nations SGA SGA Purple Loosestrife Biological Control Site Lake 2 (PL06) - Hillsdale County, MI. - August 2, 2002 South West This site is located on an impoundment in which loosestrife entirely ringed the lake. The release was conducted where the outflow is present on the southeast side of the lake. There was one release in May 1998 of 6,405 adult, egg and larvae, with an additional release of 5,120 (a,e,l) in June. Control is impressive, with severe stunting and defoliation by the summer of 2002.

Lost Nations SGA Purple Loosestrife Biological Control Site Rifle Range (PL07) - Hillsdale County, MI. - August 2, 2002 North This site is a small isolated wetland located at the game area rifle range. Some mixed vegetation is present, but primarily only loosestrife and some willow scrub at the border of the wetland. In 1997, 6,070 adults, eggs and larvae were released. Five years later, beetles are established but no reduction in loosestrife has been observed.

Waterloo Purple Loosestrife Biological Control Site (PL08) - Jackson County, MI. - August 2, 2002 East This site is a small isolated wetland located at the game area rifle range. Some mixed vegetation is present, but primarily only loosestrife and some willow scrub at the border of the wetland. In 1997, 6,070 adults, eggs and larvae were released. Five years later, beetles are established but no reduction in loosestrife has been observed. Stream bank Little observed damage

MSU Avian Disease Purple Loosestrife Biological Control Site (PL09) - Ingham County, MI. - August 2, 2002 North This site is on a wetland that has been cut in half by a road. There was a large concentration of loosestrife, in addition to grasses and shrubs when the first inoculation occurred in 1997. Just over 8,800 adults, eggs and larvae were released and the beetles became established in 1998. By the summer of 2002, loosestrife ground cover had decreased from 50-75% to 5-25% and flowering had been suppressed by about 50%.

North Lake Lansing Park Purple Loosestrife Biological Control Site (PL10) - Ingham County, MI. - August 2, 2002 West from boardwalk This particular site provides an excellent example of what loosestrife can do to a wetland when it is not controlled. The infestation is at least 30 acres in size and local residents report that loosestrife has been present since at least 1985. Since the first inoculation in 1997, great changes in beetle density and damage have been observed from year to year. In 2002, little damage was observed. East

Saginaw/Gratiot SGA Loosestrife Biological Control Site (PL11) - Gratiot County, MI. - August 6, 2002 North This is an impounded wetland which originally had dense loosestrife along the shore and among the islands. In 1997 5,600 beetles were released and by 2001 densities reached 47 per meter 2. By 2002, only scattered clumps of loosestrife remained and significant damage was evident to flowers and leaves. The native insect species Galerucella nymphaeae, a water lily feeder, is abundant here this insect has not been laboratory tested as a possible control mechanism.

St. John s Marsh Purple Loosestrife Biological Control Site (PL12) St. Clair County, MI. - August 19, 2002 South This site is a coastal marsh that was predominantly purple loosestrife when inoculated in 1997. The site has a tendency to fluctuate in water levels, especially after rainfall. Standing water can remain for long periods, probably because of the shallow water table. In 1997, 8,120 beetles were released and by 1999 colonies reached densities of 55 beetles per meter 2. In 2002, many damaged and stunted plants were visible, with significant flowering suppression and some leaf damage being noted. Phragmites and reed canary grass are other invasive species that are present at the site.

Pt. Mouillee Purple Loosestrife Biological Control Site (PL13) - Monroe County, MI. - August 19, 2002 North-East This is primarily a wet meadow with a strip of dogwood and other scrub/shrub trees present to the east of the release site. In 1997, 8,070 beetles were released and by 2002 loosestrife plants have been greatly reduced in coverage and in average height. little or no flowering can be observed. South

Allegan Hopkins Purple Loosestrife Biological Control Site (PL14) - Allegan County, MI. - August 7, 2002 North About 7,700 beetles were released in this wet meadow in 1998. The dominant plant species are grasses, some small shrubs and purple loosestrife. Establishment of the insects was observed by 1999, and while flowering has been suppressed by nearly 50%, little or no reduction in stem height or percent coverage was visible in 2002.

Holland Windmill Island Purple Loosestrife Biological Control Site (PL15) - Ottawa County, MI. - August 7, 2002 Marsh North of Road Previously a sea of purple In 1998 about 6,000 Galerucella were released on the edge of a small lake along the causeway to the Windmill Island park. The lake was nearly completely fringed by loosestrife plants. By 2002, the coverage had decreased from 75-100% to 1-5% and heavy leaf damage was visible to the remaining plants. On the West side of the causeway is a large marsh, which in 1998 was very heavily infested with purple loosestrife. In 2002, most of the loosestrife had been replaced by cattails and grasses.

Sleeping Bear Purple Loosestrife Biological Control Site Aral Rd. (PL16) - Benzie County, MI. - August 11, 2002 North In 1998 approximately 9,000 Galerucella were released in this small wet meadow. At the time, purple loosestrife covered 50-75% of the site. Beetles were established the following year, and by 2002 coverage had declined to 5-25% and significant suppression of flowering had occurred.

Reed s Lake East Purple Loosestrife Biological Control Site (PL17) - Kent County, MI. - August 7, 2002 South This is a small wetland adjoining Reed s Lake, surrounded by heavy growth of willows and other shrubs. In 1998, approximately 7,000 beetles were released and they became established by 1999. Little change has been observed, except for a slight decrease in the invader s average height and in the number of loosestrife blossoms.

Reed s Lake West Purple Loosestrife Biological Control Site (PL18) - Kent County, MI. - August 7, 2002 South This is a small marshy area near the outlet of Reed s Lake. In 1998, about 7,000 beetles were released, and colonies became established by 1999. Large numbers of beetles have been observed every year since then, but only a small change in average stem height and blossom numbers was observed in 2002.

South Lake Purple Loosestrife Biological Control Site (PL19) - Washtenaw County, MI. - August 7, 2002 North - Release site to right of tree In 1998, approximately 11,000 beetles were released at this heavily infested site on the edge of a medium sized lake. By 1999, they were well established and by 2000 populations were up to 45 per meter 2. By 2001, the average stem height in the study area had decreased from 171 cm to 118 cm and the percent coverage had decreased from 25-50% to 5-25%. Some reduction in flowering has occurred.

Davisburg Millpond Purple Loosestrife Biological Control Site (PL20) - Oakland County, MI. - August 8, 2002 East About 3,000 beetles were released in this marsh in 1999 and they had become established by 2000. As of 2001, few changes had been observed. In 2002 however, beetle densities increased sharply and when these pictures were taken loosestrife were few and far between. The remaining plants show heavy leaf damage and significantly reduced flowering.

Kellogg Biological Station Purple Loosestrife Biological Control Site (PL21) Kalamazoo County, MI. - August 14, 2002 East About 12,000 beetles were released in this marsh and had become established by 2000. As of the year 2002, few impacts have been observed in coverage, stem height, or flowering. Overview - East

GR Riverside Park Loosestrife Biological Control Site (PL22) - Ottawa County, MI. - August 7, 2002 Overview to South In 1999 about 9,000 beetles were released in this marsh fringing a small lake next to the grand river. They were established by 2000, and by 2002 there was a significant reduction in average stem height and flowering.

Kalamazoo River Loosestrife Biological Control Site Sebolt Farm (PL23) - Calhoun County, MI. - August 8, 2002 Overview to South About 10,500 beetles were released here in 1998 and they were established by 1999. As of 2002, few impacts have been observed in coverage, height or flowering.

GR Boat Launch Purple Loosestrife Biological Control Site (PL24) - Ottawa County, MI. - August 7, 2002 Overview to West About 8,500 beetles were released in 1999 into this heavily infested marsh paralleling the Grand River. By 2000 they had become established with up to 22 beetles per meter 2. No significant impacts have been observed as of 2002. Typical Loosestrife Plant

Conclusions Galerucella beetles have established populations at 100% of the sites monitored by PLP scientists. Impacts vary from site to site, ranging from no observable effect to nearly complete suppression of loosestrife. Impacts generally take 3-5 years to become visible. The first sign of impact is a gradual reduction in plant height and flowering. Re-growth of loosestrife following particularly heavy damage has been observed and is a result of beetle dispersal from the damaged areas. Cyclical damage and re-growth is expected. As initially anticipated, Galerucella beetles have not eliminated loosestrife at any of the release sites, but the beetles have reduced loosestrife to a small component of the plant community in several sites. Over the next 5 years many more release sites are expected to experience sharp reductions in loosestrife density and coverage.