|Deloach Jr, Culver|
Submitted to: Biological Control of Invasive Plants in the United States
Publication Type: Book / Chapter
Publication Acceptance Date: 6/15/2004
Publication Date: 10/31/2004
Citation: Deloach Jr, C.J., Carruthers, R.I. 2004. Saltcedar. In: Coombs, Clark, Piper and CoFrancesco, editors. Biological Control of Invasive Plants in the United States. Eugene, Oregon: Oregon State University Press. p. 311-316. Interpretive Summary: Saltcedar is an exotic shrub or small tree that was introduced into North America from Eurasia. It has infested riparian areas thoughout the western United States, Mexico and Southern Canada where it causes extensive environmental damage, water loss ranchers and municipalities and highly limits the use of infested lands by adding salts to the soil surface. USDA-ARS has worked for the past decade to develop new methods of biological control, specifically using leaf beetles from Asia and Europe to defoliate these plants. A highly successful project has now been initiated in six western states including California, Colorado, Nevada, Texas, Utah and Wyoming where these leafbeetles have been released and have established in many sites. USDA-APHIS is now planning a large-scale redistribution program that will expand the use of this biological control to many more locations. If successful, this project can save over $2000 per acre in control costs which can be very beneficial if only a portion of the $55 million acres that are infested are controlled biologically.
Technical Abstract: Saltcedar is probably the most destructive exotic, invasive weed of western riparian areas. It rapidly excludes desirable native vegetation, especially following wildfires or floods, in saline soils and in overgrazed areas; interacts synergistically with altered hydrologic cycles below dams, droughts, overgrazing, and with some control methods to increase its own competitive advantage over native plants. It dries up desert springs and small streams, alters stream geomorphology and water quality, and increases soil salinity, all of which seriously degrade wildlife habitat including that of many sensitive species of birds, fish and other animals and plants. It interferes with recreational usage of parks and natural areas. It can be controlled with aerial applications of imazapyr, or imazapyr plus glyphosate, or basal stem application or cut-stump application of triclopyr; however, these are expensive, difficult to apply in areas of rugged terrain, and aerial applications may damage native plants in natural areas of mixed vegetation. Biological control provides an environmentally compatible alternative method of control. Beetles from China and Crete (Diorhabda elongata) have been tested by USDA-ARS scientist in Albany, CA and Temple for efficacy and safety and have been permitted for release by both the US Fish and Wildlife Service and USDA-APHIS. Releases were initially made in six western states in limited release areas where cage studies verified the efficacy of these insect natural enemies. Open field releases and further verified their effectiveness in multiple field sites. For example, release of 1300 beetles in the summer of 2001 increase to millions of beetles in two seasons so that over 400 acres of saltcedar was totally defoliated in research sites in Nevada. Similar results have been seen in Colorado, Utah, and Wyoming. Additional research is being conducted to provide beetles adapted for more southern areas which should be affective in states such as California, New Mexico and Texas.