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Duan J.J.,Beneficial Insects Introduction Research Unit | Yurchenko G.,Forest Management Agency of the Russian Federation | Fuester R.,Beneficial Insects Introduction Research Unit
Environmental Entomology | Year: 2012

Field surveys were conducted from 2008 to 2011 in the Khabarovsk and Vladivostok regions of Russia to investigate the occurrence of emerald ash borer, Agrilus planipennis Fairmaire, and mortality factors affecting its immature stages. We found emerald ash borer infesting both introduced North American green ash (Fraxinus pennsylvanica Marshall) and native oriental ashes (F. mandshurica Rupr. and F. rhynchophylla Hance) in both regions. Emerald ash borer densities (larvae/m 2 of phloem area) were markedly higher on green ash (11.376.7 in the Khabarovsk area and 77245 in the Vladivostok area) than on artificially stressed Manchurian ash (2.2) or Oriental ash (1059). Mortality of emerald ash borer larvae caused by different biotic factors (woodpecker predation, host plant resistance and/or undetermined diseases, and parasitism) varied with date, site, and ash species. In general, predation of emerald ash borer larvae by woodpeckers was low. While low rates (327%) of emerald ash borer larval mortality were caused by undetermined biotic factors on green ash between 2009 and 2011, higher rates (2695%) of emerald ash borer larval mortality were caused by putative plant resistance in Oriental ash species in both regions. Little (<1%) parasitism of emerald ash borer larvae was observed in Khabarovsk; however, three hymenopteran parasitoids (Spathius sp., Atanycolus nigriventris Vojnovskaja-Krieger, and Tetrastichus planipennisi Yang) were observed attacking third-fourth instars of emerald ash borer in the Vladivostok area, parasitizing 08.3% of emerald ash borer larvae infesting Oriental ash trees and 7.362.7% of those on green ash trees (primarily by Spathius sp.) in two of the three study sites. Relevance of these findings to the classical biological control of emerald ash borer in newly invaded regions is discussed. © 2012 Entomological Society of America. Source


Faccoli M.,University of Padua | Favaro R.,University of Padua | Smith M.T.,Beneficial Insects Introduction Research Unit | Wu J.,University of Delaware
Agricultural and Forest Entomology | Year: 2015

The Asian longhorn beetle Anoplophora glabripennis is highly polyphagous and widely spread over regions with different climates. Determining the key life-history traits is important for understanding how local conditions affect its successful establishment and to develop adaptive management strategies. Field and laboratory studies were conducted from 2010 to 2012 on an A. glabripennis infestation in Northern Italy, aiming to determine its seasonal phenology, adult beetle longevity, density of successful emergence, infestation age and overwintering life history. Adult beetle emerged from infested trees from 22 May to 28 June. Ninety percent of emergence was reached around 20 July. The first 1% of emergence was accurately predicted by an accumulated degree-day model. In the laboratory, the mean longevity of males and females developed under natural conditions was 27.8±1.7 and 24.9±1.8days, respectively. In northern Italy, A. glabripennis largely overwinter as mature larvae in the xylem. The mean density of exit holes was 24.0±2.7 holes/m2 of bark, with successful emergence from branches as small as 3.2cm in diameter. Although the infestation was discovered in June 2009, the oldest exit hole found in infested trees dated from 2005. © 2014 The Royal Entomological Society. Source


Duan J.J.,Beneficial Insects Introduction Research Unit | Jennings D.E.,University of Maryland University College | Williams D.C.,Beneficial Insects Introduction Research Unit | Larson K.M.,University of Delaware
BioControl | Year: 2014

Although climate change frequently has been linked to observed shifts in the distributions or phenologies of species, little is known about the potential effects of varying temperatures on parasitoids and their relationships with hosts. Using the egg parasitoid Oobiusagrili (Hymenoptera: Encyrtidae) we examined host utilization patterns of this species across a range of temperatures (20–35 °C) to explore how changing climate could affect the interaction with its host—the emerald ash borer (EAB) (Coleoptera: Buprestidae), a serious invasive forest pest that has killed tens of millions of ash (Fraxinus spp.) trees in North America. Results from our study showed that the window of host susceptibility to O. agrili parasitism declined significantly from 14.8 to 2.6 days in an inverse second-order relationship with increasing exposure temperatures from 20 to 35 °C. In contrast, parasitoid host attack rate changed in a bell-shaped second-order relationship—i.e., increased with temperatures from 20 to 25 °C, but decreased at about the same rate when temperatures increased from 30 to 35 °C. This range of temperatures also significantly affected the development and mortality of immature parasitoids with 35 °C resulting in 100 % mortality. There was little mortality (0–4.5 %) and no significant differences in the percentage (20.9–34.9 %) of immature O. agrili that entered diapause (as mature larvae) at 20, 25, and 30 °C. However, there were significant differences in the time event of adult wasp emergence within this temperature range. The median time for 50 % of immature O. agrili emerging as adults at 20, 25, and 30 °C were 38, 18, and 17 days after parental wasp oviposition, respectively. Together these findings indicate that the non-linear and unequal temperature effects on these host utilization parameters are likely to result in differential host parasitism rates, and thus could reduce the efficacy of this parasitoid in suppressing host populations due to climate change (global warming and extreme heat). © 2014, US Government. Source


Wang X.-Y.,Chinese Academy of Forestry | Jennings D.E.,University of Maryland University College | Duan J.J.,Beneficial Insects Introduction Research Unit
Journal of Applied Ecology | Year: 2015

Parasitoids often are selected for use as biological control agents because of their high host specificity, yet such host specificity can result in strong interspecific competition. Few studies have examined whether and how various extrinsic factors (such as parasitism efficiency, i.e. the ability to optimize host-finding attack rates) influence the outcome of competition between parasitoids, even though they could have profound effects on the implementation of classical biological control programmes. To determine the potential influence of extrinsic competition and coexistence on host suppression efficacy, we compared parasitism by two larval parasitoids (Tetrastichus planipennisi and Spathius galinae) of the invasive emerald ash borer (EAB) Agrilus planipennis, under different host densities, parasitoid densities, host plant sizes and parasitoid-host ratios. Spathius galinae had significantly higher parasitism efficiency (≈4 times), but significantly lower brood size (>6 times) than that of T. planipennisi. The attack rates of hosts increased significantly with parasitoid density, whereas host density did not significantly affect multiparasitism. The parasitism rate of T. planipennisi on small host logs was significantly higher than that on large logs, while host plant (log) size had no significant impact on S. galinae parasitism. The multiparasitism rate was rather low regardless of host log size and parasitoid/host density, indicating that intrinsic competition between the two species of parasitoids might seldom occur in the field. The two species of parasitoids could therefore coexist in the same habitat, and any adverse effects on the suppression of EAB populations caused by competitive behaviour between the two species of parasitoids would likely be negligible. Synthesis and applications. Our findings suggest that introducing multiple species of parasitic natural enemies could be feasible for management of invasive species, but it is important to examine multiple extrinsic factors simultaneously when evaluating interspecific competition between them. Among these different extrinsic factors, we found that coexistence between parasitoids can be mediated by trade-offs in their parasitism efficiency and brood sizes. Thus, the differences in life-history traits of natural enemies could be used to select among biological control agents being considered for releases. Our findings suggest that introducing multiple species of parasitic natural enemies could be feasible for management of invasive species, but it is important to examine multiple extrinsic factors simultaneously when evaluating interspecific competition between them. Among these different extrinsic factors, we found that coexistence between parasitoids can be mediated by trade-offs in their parasitism efficiency and brood sizes. Thus, the differences in life-history traits of natural enemies could be used to select among biological control agents being considered for releases. © 2015 British Ecological Society. Source


Haye T.,Chinese Academy of Agricultural Sciences | Gariepy T.,Agriculture and Agri Food Canada | Hoelmer K.,Beneficial Insects Introduction Research Unit | Rossi J.-P.,755 avenue du Campus dAgropolis | And 3 more authors.
Journal of Pest Science | Year: 2015

The brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae), has emerged as a harmful invasive insect pest in North America and Europe in the 1990s and 2000s, respectively. Native to eastern Asia, this highly polyphagous pest (>120 different host plants) is spreading rapidly worldwide, notably through human activities. The increasing global importance of the pest suggests that more coordinated actions are needed to slow its spread and mitigate negative effects in invaded areas. Prevention of large-scale outbreaks will require accurate identification and effective mitigation tools to be rapidly developed and widely implemented. In this short review, we update the current distribution of H. halys, discuss potential geographic range expansion based on passive and active dispersal and provide insight on the economic, environmental and social impact associated with H. halys. © 2015 Springer-Verlag Berlin Heidelberg Source

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