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

Abstract

Populations of hymenopteran parasitoids associated with larval stages of the invasive emerald ash borer (EAB) Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) were surveyed in 2009 and 2010 in the recently invaded areas in north central United States (Michigan), where two introduced EAB larval parasitoids, Tetrastichus planipennisi Yang and Spathius agrili Yang were released for classical biological control. Results from two years of field surveys showed that several hymenopteran parasitoids have become associated with EAB in Michigan. Among these parasitoids, the gregarious species T. planipennisi was the most abundant, accounting for 93% of all parasitoid individuals collected in 2009 (immediately after field release) and 58% in 2010 (a year later after field releases). Low levels (1-5%) of parasitism of EAB larvae by T. planipennisi were consistently detected at survey sites in both years. Separately, the abundance of the native parasitoid, Atanycolus spp., increased sharply, resulting in an average parasitism rate of EAB larvae from\0.5% in 2009 to 19% in 2010. Other parasitoids such as Phasgonophora sulcata Westwood, Spathius spp., Balcha indica Mani & Kaul, Eupelmus sp., and Eurytomus sp. were much less abundant than T. planipennisi and Atanycolus spp., and each caused \1% parasitism. Besides hymenopteran parasitoids, woodpeckers consumed 32-42% of the immature EAB stages present at our study sites, while undetermined biotic factors (such as microbial disease and host tree resistance) caused 10-22% mortality of observed EAB larvae. Relevance of these findings to the potential for biological control of EAB in the invaded areas of North America is discussed.

Long-term monitoring of the introduced emerald ash borer (Coleoptera: Buprestidae) egg parasitoid, Oobius agrili (Hymenoptera: Encyrtidae), in Michigan, USA and evaluation of a newly developed monitoring technique

“…Several studies have monitored the establishment and evaluated the effectiveness of introduced larval parasitoids of EAB (Duan et al, 2012a(Duan et al, , 2013, but relatively few studies have measured the impacts of O. agrili, largely because EAB eggs are concealed in bark crevices and are difficult to find. Several sampling methods have been used to estimate rates of egg parasitism, including (1) the use of sentinel eggs (placing them under flaps of bark), (2) timed visual searches for naturally occurring EAB eggs on ash trees, (3) deployment of sentinel egg logs (short lengths of ash bearing EAB eggs) (Duan et al, , 2012b, and (4) holding ash logs or bark samples in emergence tubes for parasitoid emergence (Bauer et al, , 2012.…”

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

“…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). Since their introduction, efforts have been made to determine establishment and prevalence of these parasitoids (Duan et al 2011(Duan et al , 2012a(Duan et al , 2012b(Duan et al , 2013a(Duan et al , 2014a(Duan et al , 2015Abell et al 2014). Although the phenology of the native parasitoid Atanycolus cappaerti Marsh & Strazanac (Hymenoptera: Braconidae) attacking emerald ash borer has been described (Cappaert & McCullough 2009), no work to date has described the flight phenology of these parasitoids.…”

Progress and Challenges of Protecting North American Ash Trees from the Emerald Ash Borer Using Biological Control

“…Using this approach, average larval parasitism by T. planipennisi was~1 to 6% from 2008-2011 and increased to~30% by 2014 in both the release and control plots [81,95,96]. As more recovery work is done in this and other regions, researchers are finding a rapid spread of T. planipennisi across EAB-infested sites (Figure 2b).…”