|Deloach Jr, Culver|
Submitted to: XI Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: October 13, 2003
Publication Date: June 10, 2004
Citation: Deloach Jr, C.J., Carruthers, R.I. 2004. In: Cullen, Briese, Kriticos, Lonsdale, Morin and Scott (Eds). First results for control of saltcedar (Tamarix spp.) in the open field in the western United States. Proceeding of the XI Symposium on Biological Control of Weeds, CSIRO Cambera. p.506-513. Interpretive Summary: Saltcedar is an invasive shrub to small tree that has invaded many riparian areas in the western United States. This plant causes extensive losses to agriculture, water resources and natural areas throughout the west and now is the target of costly herbicide eradication programs in many states. For that reason, the USDA Agricultural Research Service has lead a program to develop an inexpensive, effective and environmentally sound biological control program to control this invasive species. A leaf beetle from Eurasia was located and tested for several years under quarantine conditions and then once approved through the regulatory process, was released into the open environment is six states. The biological control agent has established well at most sites, has caused extensive saltcedar defoliation and is now spreading within the release areas. This paper describes the biology and ecology of this agent and its potential to impact saltcedar over wide areas. If successful, this biological control program would save US taxpayer, municipalities and agricultural producers, million of dollars.
Technical Abstract: Saltcedars (Tamaricaceae: Tamaricales) are among the most devastating exotic weeds ever to invade western U.S. riparian ecosystems. The ARS began biological control research in 1986 at Temple, TX and in 1998 at Albany, CA. Many prospective control insects are reported in the homeland of saltcedar in Eurasia. A leaf beetle, Diorhabda elongata Brullé deserticola Chen from Fukang, China and Chilik, Kazakhstan, was released into field cages at 10 sites in Texas, Colorado, Wyoming, Utah, Nevada and California during 1999 and 2000, and into the open field at 6 of these sites in May 2001. It successfully overwintered at 4 sites north of the 38th parallel in 4 states, but not in Texas or southern California, presumably because daylength is too short at the southern sites. During the summer of 2002, we observed dramatic defoliation of saltcedar at Lovelock, NV; good defoliation at Pueblo, CO; and substantial population increases but not defoliation at Lovell, WY and Delta, UT. Diorhabda beetles from Turpan, China; Greece; Uzbekistan and Tunisia are active at shorter daylengths and are promising for control in the more southern areas. Predators (ants and birds) have reduced populations at Lovell and Delta, and at Bishop, CA and control insects with predator protective behaviors, such as gall formers, may be required in those areas.