Hardwood injury and mortality associated with two shot hole borers, Euwallacea spp., in the invaded region of southern California, USA, and the native region of Southeast Asia

Abstract

& Key message We assessed the impact of the polyphagous shot hole borer (PSHB), Euwallacea whitfordiodendrus (Schedl), and Kuroshio shot hole borer (KSHB), E. kuroshio Gomez and Hulcr, on hardwood trees in southern California, southwestern China, and northwestern Vietnam. The highest levels of mortality were recorded from 10 of 39 tree species in the survey, and these were primarily native tree species. & Context Two invasive shot hole borers represent relatively recent introductions in southern California, USA, and continue to spread and cause injury and mortality to several native and ornamental tree species. They originate from Southeast Asia. & Aims Knowledge of tree species susceptibility to these wood-boring beetles is essential to inform better pest management and to evaluate future risk for urban and wildland forests. & Methods From 2012 to 2016, ground surveys were conducted in the invaded and native regions at PSHB/KSHB-infested and PSHB/KSHB-uninfested sites to record levels of tree injury and mortality on native and ornamental tree species. & Results In California, several native species of maple, Acer, willow, Salix, and sycamore, Platanus, were infested by either PSHB or KSHB at high rates (> 70%), and comparative rate of infestation by KSHB in all trees and in native trees surpased that by PSHB, whereas rate of infestation by PSHB in ornamental trees surpassed that by KSHB. Mortality of two maple species caused by PSHB exceeded 20%, whereas background mortality rate of hardwoods was 2% in uninfested areas. & Conclusion These data should inform land managers about the tree species at most risk to injury and mortality, facilitate detection ground surveys, and direct prophylactic treatments for these invasive woodborers. Keywords Ambrosia beetles. Hardwood tree mortality. Impact assessment. Invasive species This article is part of the topical collection on Entomological issues during forest diebacks

A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China

“…Most of these introduced species were native to SE Asia ( Haack and Rabaglia 2013 ). In North America, three SE Asian species Euwallacea fornicatus (Eichhoff, 1868), E. kuroshio (Gomez & Hulcr, 2018), and Xyleborus glabratus Eichhoff, 1877, have caused major economic and ecological damage to trees in urban/suburban and natural areas ( Eskalen et al 2013 ; Boland 2016 ; Carillo et al 2016; Hughes et al 2017 ; Coleman et al 2019 ).…”

Reassessment of the Species in the Euwallacea Fornicatus (Coleoptera: Curculionidae: Scolytinae) Complex after the Rediscovery of the “Lost” Type Specimen

“…It has also been recorded from the following hosts under different names: Callerya (Fabaceae), Persea americana (Lauraceae) ([21,22] as Euwallacea sp. #1 and PSHB, respectively), Robinia (Fabaceae) [23], Sambucus (Adoxaceae), Liquidambar (Altingiaceae), Schinus (Anacardiaceae), Alnus (Betulaceae), Ricinus (Euphorbiaceae), Acacia (Fabaceae), Carya , Quercus (Fagaceae), Juglans (Juglandaceae), Umbellaria (Lauraceae), Magnolia (Magnoliaceae), Ficus , Morus (Moraceae), Eucalyptus (Myrtaceae), Fraxinus (Oleaceae), Platanus (Platanaceae), Prunus (Rosaceae), Populus , Salix (Salicaceae), Acer (Sapindaceae), Ailanthus (Simaroubaceae), and Ulmus (Ulmaceae) ([22,24] as PSHB).…”

“…Host plants. This species is known from Sambucus (Adoxaceae), Liquidambar (Altingiaceae), Schinus , Searsia (Anacardiaceae), Ambrosia , Baccharis (Asteraceae), Alnus (Betulaceae), Ricinus (Euphorbiaceae), Quercus (Fagaceae), Cassia , Persea (Lauraceae), Ficus (Moraceae), Eucalyptus (Myrtaceae), Juglans , Pterocarya (Juglandaceae), Magnolia (Magnoliaceae), Fraxinus (Oleaceae), Platanus (Platanaceae), Populus , Salix (Salicaceae), Nicotiana (Solanaceae), and Tamarix (Tamaricaceae) [24,26,27].…”

Commodity risk assessment of Albizia julibrissin plants from Israel

“…1-infestation proportion expressed as percentage) agreed by the Panel: graphical representation is shown in Figure A.1.1. The insect E. fornicatus is reported to use A. julibrissin as a host plant (Eskalen et al, 2013) The fungus F. euwallaceae is reported to use A. julibrissin as a host plant (de Beer and Paap, 2019;Coleman et al, 2019), also in Israel (Mendel et al, 2017) Some plant species are reported to be used only as feeding hosts by PSHB where reproductive life stages (e.g. tunneling larvae, male beetles) are not reported (non-reproductive host).…”