| Biological control of the spotted gum psyllid, Eucalyptolyma maidenii: a new pest on urban eucalyptus trees in Southern California.
(02XU024)
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Program
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Exotic Pests and Diseases Research Program
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Principal investigator
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D.L. Dahlsten, Insect Biology, UC Berkeley
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Host/habitat
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Eucalyptus; Landscape Trees and Shrubs
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Pest
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Spotted Gum Psyllid Eucalyptolyma maidenii
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Discipline
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Entomology
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Review panel
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Urban Systems
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Start year (duration)
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2002
(Three Years)
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Objectives
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Document the seasonal distribution and abundance of the different life stages of E. maidenii and its endemic natural enemies on lemon-scented and spotted gum Eucalyptus in southern California. Test monitoring methods to study population fluctuations and to evaluate control attempts. Screen and select natural enemies from Australia for introduction and evaluate the impact of the selected natural enemies on E. maidenii. Implement a statewide biological control program for E. maidenii.
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Project Summary
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The objective of this project is to develop a biological control program for the newly introduced psyllid pest, Eucalyptolyma maidenii (the spotted gum psyllid) on ornamental lemon-scented gum and spotted gum in southern California. The infestation of the spotted gum psyllid, first reported in Los Angeles in 2000, has resulted in pesticide spraying by urban and park organizations. Our project will attempt biological control of this pest using a specific, introduced parasitoid natural enemy. We will monitor pest populations and determine the impact of the parasitoid on these populations.
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Third-year progress
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During 2004 and 2005, we expanded sampling to three southern California counties and tested monitoring methods for the spotted gum psyllid, using both a trap for adult psyllids and foliage sampling for immature stages. We found that psyllid populations in this area generally have two high periods annually (late spring-early summer and fall), although there were some differences between coastal and inland locations. Psyllid levels usually remain low during cool winter months and also dip during the hottest summer months. Parasitoids were collected from Queensland and reared in quarantine at UC Berkeley. Specificity testing was completed on candidate species of parasitoids, and one species was determined to be an effective agent that can be developed for rearing and release.
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Second-year progress
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During the 2003-2004 period we expanded sampling to three southern California counties and tested monitoring methods for the spotted gum psyllid, using both a trap for adult psyllids and foliage sampling for immature stages. We found that psyllid populations in this area generally have two high periods annually (late spring-early summer and fall). Psyllid levels usually remain low during cool winter months and also dip during the hottest summer months. Specificity testing was completed on candidate species of parasitoids and one species was determined to be an effective agent that can be developed for rearing and release. Contacts have been made with Australian scientists to collect and ship the parasitoid to California.
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First-year progress
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During the 2002-2003 period we expanded sampling to three southern California counties and tested monitoring methods for the spotted gum psyllid, using both a trap for adult psyllids and foliage sampling for immature stages. We found that psyllid populations in this area generally have two high periods annually (late spring-early summer and fall). Psyllid levels usually remain low during cool winter months and also dip during the hottest summer months. On plots where property managers applied pesticides, we found either no effect or a short-term effect on psyllid levels. We undertook two trips to Australia to explore for potential biological control agents. We imported and tested a number of insects, at least one of which may be a good control agent against the psyllid. Another trip needs to be made to obtain enough of these beneficial insects to establish a colony in California.
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