Submitted to: Extension Publications
Publication Type: Other
Publication Acceptance Date: September 10, 2003
Publication Date: October 1, 2003
Citation: Knutson, A., Muegge, M., DeLoach, C.J. 2003. Biological control of saltcedar. Texas Cooperative Extension L-5444 (Brochure).
Interpretive Summary: Saltcedars are small trees or shrubs in the plant genus Tamarix that were introduced from the Old World into the western United States, beginning in 1823, as ornamentals and to control streambank erosion. They soon escaped cultivation and have become major weeds along western streams and lake shores. A leaf beetle from Asia, Diorhabda elongata, that can develop only on Tamarix, was tested overseas and in quarantine in the United States, was found to be both safe to other plants and highly damaging to saltcedars, and has been released at 6 locations in Texas since July 2003. Intensive monitoring of the degree of control of saltcedar and the effects of control on native plant and animal communities is now underway. The introduction of natural enemies of saltcedar, like the leaf beetle Diorhabda, will provide sustainable, environmentally-friendly control of this weed.
Saltcedars are exotic shrubs or small trees in the genus Tamarix that were introduced into western United States beginning in 1823 as ornamentals, windbreaks and to reduce streambank erosion. However, they have escaped cultivation and now occupy large areas of riparian habitats where they cause great losses in stream flow and groundwater, displace native plant communities, and degrade wildlife habitat. Biological control, through the introduction of host-specific insects that control saltcedars in their homeland in the Old World can complement ongoing herbicidal control programs by providing environmentally friendly, self-sustaining, and permanent and inexpensive control. The first insect biological control agent, a leaf beetle Diorhabda elongata, from Crete, Tunisia and China has been tested in field cages and those from Crete have been released and have overwintered in the open field in Texas. Successful establishment of these beetles would provide control of scattered or large saltcedar stands, and that would not harm non-target plants in environmentally sensitive areas.