The elm leaf beetle (ELB), Xanthogaleruca luteola, is the most commonly treated pest of elms and is ranked as the second most important urban tree pest in the western United States.
In 1995 the Sacramento Tree Foundation, the City of Sacramento Neighborhood Services and the University of California began a co-operative effort to develop and implement an integrated pest management program for the elm leaf beetle in Sacramento. This program was based on work previously completed by Dahlsten et al and adapted a user friendly monitoring technique to locate areas of beetle activity or "hot spots". Control efforts could then be directed toward these "hot spots" instead of treating all trees on a calendar basis. Between 1995 and 1999 progressively larger areas of the city were set aside to be managed under the monitoring program and by the 1999 season all susceptible street trees in the city were being monitored totaling over 2200 trees. Trees were sampled at the egg peak of each generation as determined by a degree day model and only those trees with beetle populations high enough to defoliate trees above the acceptable damage level were treated. By using this monitoring program we were able to reduce the number of trees treated from 100% of susceptible trees to less than 10%.
Several control measures compatible with the monitoring program were evaluated. Releases of a new strain of the egg parasitoid Oomyzus gallerucae were largely unsuccessful, as the parasitoid does not appear to overwinter well in California. Foliar applications of Bacillus thuringiensis var. San Diego combined with horticultural oil have provided adequate control when applied twice per generation spaced one week apart. Systemic injections of Vivid (abermectin) and Imicide (imidacloprid) provide good control and are compatible with the monitoring program.
Species 1: Coleoptera Chrysomelidae Xanthogaleruca luteola (elm leaf beetle)
Species 2: Hymenoptera Eulophidae Oomyzus gallerucae
Keywords: IPM, urban forest
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA