An exploratory survey for the emerald ash borer, Agrilus planipennis, and its natural enemies was conducted in China during October and November 2003. We examined 29 field plots in six provinces. We visually inspected living Fraxinus chinensis, F. mandshurica, F. pennsylvanica, F. rhynchophylla, and F. velutina then peeled off the bark in search of A. planipennis and associated natural enemies. We found active A. planipennis infestations in nine of the 29 field plots, including plots in the provinces of Hebei, Heilongjiang, Jilin, Liaoning, and the provincial level city of Tianjin. Signs of past A. planipennis infestations were found in five of the 20 plots where no active infestations were present. The distribution of A. planipennis was patchy within the forest, and larval densities varied greatly among trees and at different heights within the same tree. Agrilus planipennis densities ranged from 0 to 284 larvae/m2 of bark surface for 1-m log sections. The Nearctic ash species, F. pennsylvanica and F. velutina, planted in China were apparently more susceptible to A. planipennis attack than were the native Chinese ash species. Similarly, ash trees growing along streets or in plantations or city parks were more susceptible to A. planipennis infestation compared with trees in natural forests. We identified two species of natural enemies attacking A. planipennis during this survey. In Changchun City, Jilin Province and Guangang District, Tianjin City, we found a previously reported but undescribed species of Spathius sp. (Braconidae) parasitizing an average of 6.3% A. planipennis larvae in individual trees, ranging from 0 to 50%. In Changchun City, Jilin Province and in Benxi County, Liaoning Province, we discovered a previously unknown gregarious endoparasitoid of A. planipennis larvae, Tetrastichus nov. sp. (Eulophidae), with a total parasitism rate of 6.6% in individual trees, ranging from 0 to 50%. We discussed the potential role of natural enemies in the management of A. planipennis in North America.
Liu, Houping; Bauer, Leah S.; Gao, Ruitong; Zhao, Tonghai; Petrice, Toby R.; and Haack, Robert A.
"Exploratory Survey for the Emerald Ash Borer, Agrilus Planipennis (Coleoptera: Buprestidae), and Its Natural Enemies in China,"
The Great Lakes Entomologist, vol 36
Available at: https://scholar.valpo.edu/tgle/vol36/iss2/11