Freeze stress of deciduous trees induces attacks by opportunistic ambrosia beetles

Abstract

1 A broad host range and the utilization of living but weakened trees contribute, in part, to the invasion success of ambrosia beetles (Curculionidae: Scolytinae). The present study assessed the capability of freeze stress to induce attacks by ambrosia beetles. 2 Freeze stress predisposed Cercis canadensis L., Cornus florida L., Malus pumilaMill. and Styrax japonicus Sieb. to attack under field conditions, although no attacks occurred on untreated trees. More attacks occurred on freeze-stressed versus flood-stressed M. pumila in Virginia but not for S. japonicus in Ohio. Attacks on flooded trees were skewed towards the base of the trunk, whereas attacks on freeze-stressed trees mainly occurred around the upper regions of the trunk and into the branches. The predominant species recovered were Anisandrus maiche Stark and Xylosandrus germanus (Blandford) in Ohio, and Xylosandrus crassiusculus (Motschulsky) in Virginia. 3 Ethanol emissions from trunks of S. japonicus were detected by solid phase microextraction-gas chromatography-mass spectrometry at 1 day after imposing freeze stress, peaking 4 days after injury. 4 Trees with an intolerance of freeze stress are predicted to be vulnerable to attack, especially when subjected to mild winter temperatures followed by late-spring freezes. Freeze stress could thereby facilitate the destructiveness of exotic ambrosia beetles.

Long-Lasting Insecticide Netting for Protecting Tree Stems from Attack by Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae)

“…Thus, it is unclear what species of ambrosia beetles were responsible for tree attacks within these regions. Still, previous dissections of experimentally-stressed trees found that Xylosandrus crassiusculus (Motschulsky) and X. germanus were the dominant species recovered in Virginia [13,26,36]; Cnestus mutilatus and X. crassiusculus were the dominant species recovered in Tennessee [37]; and Hypothenemus dissimilis (Zimmermann), Xylosandrus compactus (Eichhoff), and X. crassiusculus were the dominant species in Mississippi [36]. Differences in the seasonal activity and composition of Xyleborine ambrosia beetles could account for variability in efficacy of the insecticide treated netting observed between years and locations.…”

“…Xylosandrus germanus is a dominant exotic species in Ohio and upper Midwestern US [5], but the distribution of A. maiche has increased since first being reported in North America in 2009 [34,35]. The incidence of A. maiche in experimentally-stressed trees deployed in Ohio has also increased [12,13,36]. Notably, caution must be taken to accurately distinguish between A. maiche and X. germanus since their morphology is very similar, except the procoxae of A. maiche are contiguous [34,35].…”

“…Despite an extensive host range, trees emitting ethanol in response to abiotic and biotic stressors are preferentially attacked by a variety of xyleborine ambrosia beetles [5]. A variety of stressors can induce the production and emission of ethanol, including flood stress [11,12], freeze stress [13], and pathogen infection [14], thereby triggering attacks by ambrosia beetles. Maintaining tree health is a fundamental strategy to managing ambrosia beetles in nurseries, orchards, and groves.…”

Distribution, Habitat Preference, and Management of the Invasive Ambrosia Beetle Xylosandrus germanus (Coleoptera: Curculionidae, Scolytinae) in European Forests with an Emphasis on the West Carpathians

“…Climate change within Europe [119,120], and specifically mild winters, could be assisting the spread of X. germanus. Similarly, freeze stress events following mild winters could also increase the availability of suitable host material and lead to an increased incidence of attacks [97,98]. Heavy precipitation and flood stress can also predispose trees to attack.…”

“…A variety of stressors can induce the emission of ethanol from living but weakened trees, including flood and drought stress, freeze stress, girdling, impaired root function, root and crown disturbance, pollutants, and pathogens [92][93][94][95][96]. In particular, flood stress and freeze stress have been demonstrated to induce the emission of ethanol and predisposes trees to attack by ambrosia beetles [85,[96][97][98][99]. The emission of ethanol from aging logs also attracts and induces attacks by X. germanus and other ambrosia beetles [46,67,[100][101][102][103].…”