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Eucalyptus and Die-off
In 1990, the eucalyptus long-horned borer was
inadvertently brought to San Diego and
spread.Two decades
later, 300 massive, 100-year old eucalyptus on
campus had been killed.
Eucalyptus
are native to Australia where infestations are
partially held in check by wasps that prey on the
borer. In 1992, as the
die-off continued, a plan was initiated to
introduce the Australian wasps and to replace the
now vulnerable eucalyptus with species native to
the area.
In 1998, the red
gum lerp psyllid, Glycaspis brimblecombei, which sucks nutrients from
the eucalyptus and clogs gas-exchange pores needed
for photosynthesis, was detected on campus. A crystallized honeydew called a lerp, protects the mymphs
from both predators and insecticidal sprays. Heavy honey dew leads to the growth of sooty mold. By 1999
the psyllid was found infesting more than 50 campus
eucalyptus, leading to year-round rather than
seasonal leaf drop. In southern
California, where this invading psyllid first
appeared, trees began dying.
At least 14 other introduced insects attack Eucalyptus trees in California.
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