Genetic analysis of emerald ash borer (Agrilus planipennis Fairmaire) populations in Asia and North America

Abstract

Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive pest of North American ash (Fraxinus spp.) trees first discovered outside of its native range of northeastern Asia in 2002. EAB spread from its initial zone of discovery in the Detroit, Michigan and Windsor, Ontario metropolitan areas, in large part, from inadvertent human-assisted movement of infested ash materials. EAB infestations are now known in 15 US states and two Canadian provinces. The primary goal of this study was to use molecular markers to characterize the population genetic structure of EAB in its native and introduced range. This information may provide valuable insights on the geographic origin, potential host range, invasion potential, and additional biological control agents for ongoing management efforts of this destructive wood-boring beetle. EAB were collected from 17 localities in its native Asian range and from 7 localities in North America, and population structure analyzed using mtDNA gene sequences, AFLP fingerprints, and alleles at 2 microsatellite loci. Analysis of mtDNA cytochrome oxidase subunit I gene (COI; 439 bp) sequences revealed all North American individuals carry a common mtDNA haplotype also found in China and South Korea. Additional mtDNA haplotypes observed in China and South Korea differed from the common haplotype by 1-2 nucleotide substitutions and a single individual from Japan differed by 21 nucleotide changes (4.8%). Analysis using AFLP fingerprints (108 loci) indicated Asian populations were more highly variable, yet had less overall population structure, than the North American populations. North American populations appear most closely related to populations in our sample from the Chinese provinces of Hebei and Tianjin City. Further, population assignment tests assigned 88% of the individual beetles from North America to either Hebei or Tianjin City.

Modest Effects of Host on the Cold Hardiness of Emerald Ash Borer †

“…If A. planipennis larvae are able to adjust their cold hardiness in response to these cues, our data seem to show a lower limit to A. planipennis' capacity to cold harden: the fall and winter of 2013-2014 were colder than average, but supercooling points and the mortality from freezing were not statistically different from the results collected during the more typical Minnesota winter of 2012-2013. Potential genetic differences in populations of A. planipennis could also explain different reports of cold tolerance, but genetic testing suggests that the U.S. populations most likely stem from a single introduction [59]. Regional differences in the quality of host species could also be a factor, but the attribute of the host that could drive these differences remains to be identified.…”

Population responses of hymenopteran parasitoids to the emerald ash borer (Coleoptera: Buprestidae) in recently invaded areas in north central United States

“…The attack of EAB larvae by several hymenopteran parasitoids in Michigan (the first invaded region) is not surprising as EAB larvae are also attacked by several species of parasitoids in northeast Asia, the likely area of origin (Liu et al 2003;Liu and Bauer 2006;Bray et al 2011;Duan et al 2011). In addition, there are many examples where a single insect host is attacked by a range of parasitoid species (Hawkins 1994;Memmott et al 1994;Parry 1995).…”

Factors Affecting the Flight Capacity of <I>Tetrastichus planipennisi</I> (Hymenoptera: Eulophidae), a Classical Biological Control Agent of <I>Agrilus planipennis</I> (Coleoptera: Buprestidae)

“…The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive beetle from China that has killed hundreds of millions of ash trees (Fraxinus species; Oleaceae) in North America since it was detected in 2002 (Haack et al 2002;Cappaert et al 2005;Poland & McCullough 2006;Bray et al 2011;Herms & McCullough 2014;Emerald Ash Borer Information Network 2016). Three emerald ash borer parasitoids from China were first released in Michigan, USA, in 2007 as part of a classical biological control program (Bauer et al 2007(Bauer et al , 2008(Bauer et al , 2015aUSDA APHIS 2007): 2 gregarious larval parasitoid species -Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) (Liu et al 2003;Yang et al 2005) and Spathius agrili Yang (Hymenoptera: Braconidae) (Liu et al 2003;Yang et al 2006) -and 1 egg parasitoid species, Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae) (Zhang et al 2005).…”