Biology
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.
Status
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.
Weeds Affected
This beetle is a biological control agent for Salt
Cedar.
Literature
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.
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