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Purple Loosestrife Biological Control Agents Galerucella calmariensis and Galerucella pusilla are two leaf-feeding beetles that belong to the insect family Chrysomelidae. They have similar life histories and are found in the same types of wetland habitats. Adult Galerucella calmariensis beetles are 3 to 5 mm long and light brown in color, with a dense covering of fine hair. The elytra, or wing covers, may have dark stripes along the outer edges, and there is a black marking in the center of the pronotum (the region below the head). G. pusilla is similar in appearance to G. calmariensis but is slightly smaller, 3 to 4 mm in length, and appears more flattened than the convex-shaped G. calmariensis. G. pusilla adults lack the dark striping on the elytra, but instead may have the appearance of "shoulder pads". |
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Galerucella
beetles
overwinter as adults in the soil or litter. They emerge in the spring in April
and May to begin feeding on young leaves and buds of purple loosestrife
(Lythrum salicaria). Mating occurs after a seven-day feeding
period. Female Galerucella beetles deposit eggs during
their oviposition period from May through July, with highest
egg production occurring in June. The round, opaque eggs are
laid in clusters of two to ten on purple loosestrife stems and
leaves. Eggs are white or beige in color and are covered with
a line of dark excrement. The eggs hatch in approximately one
to two weeks. Young beetle larvae feed on the upper parts of purple loosestrife, concentrating on leaf and flower buds. Older larvae feed on all plant parts. Mature larvae move off of the plant to pupate in plant debris or in soil beneath the host plant. The new generation adults that emerge in late summer feed on purple loosestrife for approximately one week and may go through a short oviposition period. Adults then move underground or in leaf litter to overwinter from September until the following spring. There is usually one generation of beetles produced per year. It takes six weeks for a Galerucella beetle to develop from egg to adult. Galerucella feeding damage to purple loosestrife leaves and flower buds may occur during the entire growing season of the host plant. At high beetle populations, defoliation of purple loosestrife may occur. |
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For more information contact Donna Ellis, State Survey Coordinator, University of Connecticut Department of Plant Science, Telephone (860)486-6448; FAX (860)486-0682; email address: donna.ellis@uconn.edu
Links: CERIS (Center for Environmental and Regulatory Information Systems
This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.
The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.
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