Tetrastichus planipennisi (Yang)
Significance: The Emerald ash borer (EAB), Agrilus planipennis Fairmaire, a native insect of eastern Asia, has been one of the most significant new pest introductions in North America in recent memory. Since the first detection in Michigan in 2002, the beetle has killed millions of ash trees in parts of the United States and Canada. To date, the only partially effective control measures for limiting the spread of this pest has been to conduct intensive surveys, to remove the dead and dying (infested) trees, to cut ash-free buffer zones, and to limit the man-made movement of pathways that might spread the insect, such as firewood. EAB has historically been considered a rather minor pest in most parts of China, although in some locations it can infest a large number of trees and lead to significant tree mortality. During a survey of parts of China, several parasitoids of EAB were identified; one undescribed species of Tetrastichus was found to be an abundant natural enemy of EAB in parts of northeast China. Yang et al. (2006) provide a detailed taxonomic description of this new species (Tetrastichus planipennisi Yang). Reported as a gregarious larval endoparasitoid of EAB larvae, T. planipennisi produces 56-92 offspring from a single EAB host. The parasitoids develop from eggs to larvae within an EAB larva, which remains alive until its last instar. The wasp larvae then emerge from the dead larva and chew exit holes through the bark of the tree. These wasps may have four generations per year in northeastern China; adults live approximately two weeks in captivity at 25 C. This new parasitoid has the potential to be a significant biocontrol agent for EAB in North America and elsewhere.
Hosts: Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)
Yang, Z.-qi. J.S. Strazanac, Y.-X. Yao, and X.-Y. Wang. (2006). A New Species of Emerald Ash Borer Parasitoid from China Belonging to the Genus TetrastichusHaliday (Hymneoptera: Eulophidae). Proc. Entomol. Soc . Wash. Vol. 108 (3):550-558.