-- California's troubled red gum eucalyptus trees, under attack
for the last two years from a fast-spreading insect infestation,
may get some relief on Wednesday (June 7) from a tiny Australian
wasp discovered by Donald Dahlsten, a scientist at the University
of California, Berkeley. The wasp, to be released in small numbers
in North Hollywood, may be able to control the infestation and
begin to save the endangered trees.
under attack in 30 California counties from the redgum lerp
psyllid, Glycaspis brimblecombei, a small, flying insect that
feeds on plant juices. It has caused much concern in the state
since it was first found in June 1998 in Los Angeles County.
Collected on 16 different varieties of eucalyptus in California,
the psyllid is causing the most trouble on redgum, Eucalyptus
camaldulensis, a common ornamental species in the state. After
infestation, trees rapidly lose their leaves and begin to
produce a sticky honeydew that dirties cars, buildings and
sidewalks. It is not known how often the trees can defoliate
and still survive.
has shown that certain species of Psyllaephagus parasitic
wasps that he collected last summer in Australia may be able
to bring the psyllid population under control by laying eggs
within the insect bodies and destroying them. The wasps have
been under surveillance for the last year at UC Berkeley.
This week, 100 females will be released to treat 20 trees
in Valley Village Park in North Hollywood.
have low numbers of parasites right now and are trying to
build up our numbers," said Dahlsten, a professor of
environmental science, policy and management and biological
control in the UC Berkeley College of Natural Resources. "We
will be releasing all summer, and we hope that the parasitoids
will spread as rapidly as the other parasitoids that we have
released to control other species of psyllids in the past,
making multiple releases unnecessary."
is credited with saving the state's foliage industry in 1991-93
from a disaster on a species of eucalyptus used in the flower
trade. It would have cost California's eucalyptus growers
millions of dollars to control the problem year after year
had Dahlsten not discovered an insect cure.
by the United States Department of Agriculture Animal and
Plant Health Inspection Service (APHIS), this week's release
will be conducted by the Los Angeles Department of Parks and
Recreation, the Los Angeles Bureau of Street Services and
the Los Angeles Zoo. Additional funding was provided by the
University of California's Integrated Pest Management Project
and by cities and agencies in Orange, San Diego and Los Angeles