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INSECTS ATTACKING EUCALYPTUS
Phoracantha semipunctata
(Fab.) & Phorocantha recurva Newman Coleoptera: Cerambycidae (Contacts) CLICK on Photos to enlarge & search for
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Cases Eucalyptus trees
had few insect pests or diseases for over a century in California However, a community of at least three
feeding guilds of insects, including borers, defoliators and sap-feeding
insects gradually invaded but most are not posing serious threats to the
survival of some eucalyptus species where irrigation is adequate (Paine et
al, 2000). Eucalyptus
Longhorn Beetles Of
particular importance are the Longhorn borers, Phoracantha semipunctata
F., P. recurva; Tortoise beetle, Trachymela sloanei, Snout beetle, Gonipterus
scutellatus Gyllenhal, Blue gum psyllid, Ctenarytaina eucalypti,
red gum lerp psyllid, Glycaspis brimblecombei. Thus far these insects primarily kill
temperate zone eucalyptus trees. The
more tropical eucalyptus species that produce a copious amount of resinous
substances under the bark, appear to be relatively immune to successful
attack. Efforts to secure natural
enemies of these pests were initiated at the University of California,
Riverside. Natural enemies of the
beetles that are considered as candidates for dissemination are an egg
parasitoid, Avetianella longoi, and the ichneumonid, Helcostizus rufiscutum Cushman. The parasitoid Patasson nitens (Girault) was imported
from South Africa to combat Eucalyptus Snout Beetle. Based on the earlier success of this
parasitoid in South Africa (see <ch-42.htm>),
biological control would be expected to be successful in California. However, the work on other pests s in
progress and too new to report definite results, although at least one
species of parasitic Hymenoptera appears to be established. As of March 2001, many of the eucalyptus
species that were originally introduced from Tasmania and southern portions
of the Australian continent are in the final stages of mortality. The eucalyptus species originating from
more tropical latitudes have thus far survived quite well, probably due to
their ability to secrete more copious resin.
The picture becomes more uncertain as new species of invaded
psyllids reduce the vigor of these
trees. REFERENCES: [Additional references may be
found at: MELVYL
Library ] Dahlsten, D. L., E. P. Hansen, R. L. Zuparka
& R. B. Norgaard. 1998a.
Biological control of the blue gum psyllid proves economically
beneficial. Calif. Agric. 52(1): 35-40. Dahlsten, D. L., D. L. Rowney, W. A. Copper, et al. 1998b.
Parasitoid wasp controls blue gum psyllid. Calif. Agric. 52(1): 31-34. Hanks, L. M., J. G. Millar and T. D. Paine. 1995.
Biological constraints on host range expansion by the wood-boring beetle
Phoracantha semipunctata F.
(Coleoptera: Cerambycidae). Ann.
Entomol. Soc. Am. 88: 183-188. Hanks, L. M., J. R. Gould, T. D. Paine, J. G. Millar and Q.
Wang. 1995. Biology and host relations of Avetianella longoi, an egg parasitoid of the Eucalyptus
longhorned borer. Annals Ent.
Soc. Am. 88: 666-671. Hanks, L. M., T. D. Paine, J. G. Millar and J. L. Hom. 1994. Variation among Eucalyptus species in resistance to eucalyptus longhorned borer
in southern California. Entomol. exp.
appl. 74:185-194. Hanks, L.M., J.G. Millar, and T.D. Paine. 1997.
Host range expansion of Helcostizus
rufiscutum Cushman (Hymenoptera: Ichneumonidae) to include Phoracantha semipunctata F.
(Coleoptera: Cerambycidae) in California. Pan-Pac. Entomol., 73: 190-191. Hanks, L.M., T.D. Paine, and J.G. Millar. 1996.
A tiny wasp comes to the aid of California's Eucalyptus trees. Calif. Agric. 50 (May-June): 14-16. Paine, T. D., J. G. Millar and L. M. Hanks. 1995.
Biology of the Eucalyptus longhorned borer in California and
development of an integrated management program for the urban forest. Calif. Agric. 49 (Jan.-Feb.):34-37 Paine, T.D., J.G. Millar, T.S. Bellows, and L.M. Hanks. 1997. Enlisting an under-appreciated
clientele: public participation in distribution and evaluation of natural
enemies in urban landscapes. American Entomologist 43: 163-172. Paine, T. D., D. L. Dahlsten, J. G. Millar, M. S. Hoddle & L.
M. Hanks. 2000. UC scientists apply IPM techniques to new
eucalyptus pests. Calif. Agric.
54(6): 8-13. Scriven, G. T., E. L. Reeves & R. F. Luck. 1986.
Beetle from Australia threatens eucalyptus. Calif. Agric. 40(4):
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