Galerucella spp. 
<<back to purple loosestrife
Common Name
Loosestrife beetles
Weed Impacted
The black-margined loosestrife beetle (Galerucella calmariensis) and the golden loosestrife beetle (G. pusilla) attack purple loosestrife. Adults and larvae suppress plant growth and reproduction by feeding heavily on leaves, stems, and buds. Both of these beetles will feed on a few other plants, but do not reproduce on those hosts. No long term nontarget impacts have been reported.
Insect Description
Galerucella calmariensis is orangish-brown, 3-5 mm (approximately 1/8 to 3/16 inch) long, with dark bands along the wing margins and a dark, triangular marking behind the head (G. calmariensis pictured). Galerucella pusilla is nearly identical, but lacks dark markings on its wings and back and tends to be slightly smaller. They can sometimes be difficult to distinguish in the field.
Life Cycle
Adults typically emerge from overwintering in late April. Females lay eggs from May to June, and the eggs hatch after about 12 days. Larvae begin feeding on young buds and leaves at the shoot tips, then feed on other leaves. Galerucella calmariensis larvae feed for about two weeks, then enter the soil or spongy stem tissue (in standing water) to pupate. Galerucella pusilla larvae may feed for as many as six weeks, but development time for an individual larva is still about 14 days. Pupation lasts for about a week, and new adults emerge between July and August. Females from the new generation may lay eggs from August to September if they emerge before mid-July. Adults overwinter in soil litter near the host plant.
Field Identification
The presence of loosestrife beetles can be indicated by defoliated, skeletonized plants or by large, gray areas of dead plants. When Galurucella spp. occur with loosestrife weevils (Hylobius transversovittatus and Nanophyes marmoratus), they can be distinguished by the absence of a snout.
Availability
These beetles are readily available throughout the northern United States. Adults are usually collected in late April to early May and again in late July to early August. To inquire about availability and to request this biocontrol agent, please download, complete and submit this form.
Comments
Galerucella spp. have built strong populations at most release sites, and purple loosestrife biomass at several sites in Washington and Oregon has been reduced by as much as 90%.
Using the Agent: Integrated Weed Management (IWM)
These insects can be used in combination with the loosestrife root-feeding weevil, Hylobius transversovittatus. Releases should be made only where loosestrife infestations are large and immediate eradication is not the primary goal.
Smaller populations of loosestrife can be hand-pulled, dug, or smothered. Mowing will likely only contribute to the spread of loosestrife, but when followed promptly by smothering, burning, or spraying, it may allow for more effective treatment. Repeated cultivation can help to weaken plants.
Burning will not control loosestrife, but it may promote earlier germination and help reduce the existing seed bank. Seedlings can then be pulled or sprayed.
Some herbicides have been shown to reduce loosestrife; however, infestations often occur in or around environmentally sensitive areas (lakes, streams, wetlands, etc.) where herbicide treatment may not be an option. Consult with your county weed office, Extension office or an IWM practitioner to determine which herbicide treatments are safe and appropriate.
Physical, mechanical, and/or herbicide treatments should not be applied where insect agents are active. Using these measures in areas of release can be detrimental to the establishment and maintenance of strong agent populations.
Any treatment of loosestrife should include revegetation with native or other desirable plants. Revegetation promotes competition between plants, which can stress weeds and allow for more effective treatments. To learn more about revegetation and IWM, click here.
References
Coombs, E. M., J. K. Clark, G. L. Piper, and A. F. Cofrancesco, Jr. 2004. Biological Control of Invasive Plants in the United States. Western Society of Weed Science, Oregon State Univ. Press, Corvallis.
Wilson, L. M., M. Schwarzlaender, B. Blossey, and C. B. Randall. 2004. Biology and Biological Control of Purple Loosestrife. USDA Forest Service, FHTET-04-12.
Photo Credits
IWCP Staff
Secondary content using h2 tag. Column 2
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Heading using the h3tag
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.