Submitted to: Proceedings of the Emerald Ash Borer and Asian Longhorned Beetle Research and Development Review 2006
Publication Type: Abstract only
Publication Acceptance Date: 12/18/2006
Publication Date: 3/20/2007
Citation: Fuester, R.W., Zou, D., Bray, A., Zhao, T., Bauer, L., Liu, H., Yang, Z. 2007. Explorations for Natural Enemies of Emerald Ash Borer in China, 2006. Proceedings of the Emerald Ash Borer and Asian Longhorned Beetle Research and Development Review 2006. USDA Forest Service. FHTET-2007-04. p. 66-67. Interpretive Summary:
Technical Abstract: An exploratory survey for the emerald ash borer (EAB), Agrilus planipennis, and its natural enemies was made in China during July-August, 2006. We visited 11 field plots in four provinces. We visually inspected living Fraxinus chinensis, F. mandshurica, F. rhynchophylla, and F. velutina, then peeled or chipped off the bark in search of EAB and associated natural enemies. We found active EAB infestations in five of the 11 field plots, and collected material from all four provinces: Hebei, Jilin, Liaoning, and Tianjin. Signs of earlier EAB infestations were found at the other six sites where no active infestations were present. The abundance of EAB was highly variable, and larval densities ranged from 0-50 larvae/sq. meter of bark surface. Velvet ash (F. velutina), a North American species often planted in China, sustained higher levels of EAB damage than the Oriental species of ash, suggesting that the latter have better defense mechanisms for resisting attacks by this pest. Likewise, ash trees growing along streets or highways or in plantations and city parks seemed to be more susceptible to EAB infestations than those growing in natural forests. We recovered two species of parasitoids during this survey, both of which had been previously recorded from EAB. The first species was Spathius agrili Yang (Hymenoptera: Braconidae), a gregarious ectoparasitoid that occurs in Tianjin and Jilin Provinces. Parasitism by this species ranged from 0 to 4 % and averaged 1%. The second species was Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae), a gregarious endoparasitoid that occurs in Liaoning and Jilin Provinces. Parasitism by T. planipennisi ranged 0-36% and averaged 8%. Some of the sites visited in 2006 were the same or near those visited in an earlier survey for natural enemies of EAB, so any additional explorations should be focused in different areas. Perhaps the most promising areas to look for specialized natural enemies of EAB would be the region in Heilongjiang province straddling the 130th meridian and adjacent areas of Russia. This region has deciduous and pine-deciduous forests containing substantial components of ash (Fraxinus spp.).