Diorhabda elongata Brulle
Both adults and larvae feed on the foliage of saltcedar, their only known host plant. This species occurs in western China and eastern Kazakhstan. Eggs are laid in masses of 2-20 on foliage and hatch in about 7-10 days. Larvae are black with two longitudinal yellow stripes and complete three instars. Mature larvae are about 8 mm long and enter a prepupa stage. The prepupa does not feed but drops to the ground and searches for a pupation site. Pupation occurs on the soil surface beneath leaf litter or in soil cracks. Development from egg to adult requires about 3-4 weeks.
Diorabda elongata is the first natural enemy approved for release as a biological control agent of saltcedar in the US. Permits for secure field cage releases were approved for eight sites in six states, California, Nevada, Colorado, Utah, Wyoming and Texas, in July, 1999. Studies of beetle reproduction and damage to saltcedar inside field cages were conducted in 1999. Plans call for cages to be opened to release the beetle in 2000 to allow further studies on beetles dispersal, reproduction and damage to saltcedar at the eight study sites. These studies, along with monitoring the recovery of native vegetation, will continue for three years. The results will provide a scientific basis for informed decisions regarding further releases of beetles at other sites. This intensive monitoring and study is necessary since an endangered bird, the southwestern willow flycatcher, uses saltcedar as a nesting site in parts of Arizona, New Mexico and Nevada.
This beetle is a biological control agent for Salt Cedar.
DeLoach, C. Jack. 1996. Saltcedar Biological Control: Methodology, Exploration, Laboratory Trials, Proposals for Field Release and Expected Environmental Effects. Saltcedar Management and Riparian Restoration Workshop. Las Vegas, NV. US. Fish and Wildlife.