PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Eucalypt psyllids in California
EUCALYPT PSYLLIDS IN CALIFORNIA
Forest Health News 113, November 2001
Like their counterparts in New Zealand, eucalypt growers in
California continue to experience problems with recurring
introductions of Australian Eucalyptus psyllids.
The blue gum psyllid, Ctenarytaina eucalypti, reached
California in 1991 where it caused problems in ornamental
eucalypts grown for the flower industry. Biological control
was initiated using the same parasitoid that attacks this psyllid
in New Zealand, Psyllaephagus pilosus.
The red gum psyllid, Glycaspis brimlecombei, became
established in California in 1998 (FHNews 91:1), and affected
the widely planted Eucalyptus camaldulensis. Its impact on
host trees was reminiscent of that made at about the same time
by the brown lace lerp, Cardiaspina fiscella, on E. saligna and
E. botryoides trees in this country. A biological control
initiative has been launched against the red gum pysllid using
an Australian parasitoid, Psyllaephagus bliteus. P. bliteus was
found parasitising Glycaspis granulata in New Zealand in
1999, under the name P. quadricyclus (FHNews 96:1).
A biological control programme has also been initiated against
the latest arrival, Eucalyptolyma maideni, which builds lerps
(protecting covers) on leaves of the bloodwood species
Eucalyptus citriodora and E. maculata . Since reaching
California in August 2000, this psyllid has caused extensive
defoliation and has spread to a number of new areas.
Californian entomologists will search for suitable host-specific
parasitoid species in Australia, as part of the control
programme. Eucalyptolyma maideni is also present in New
Zealand, but has not caused significant health problems here.
(Toni Withers, Forest Research)
