National monitoring of two non-nativespecies in Slovakia: Ips duplicatus and Xylosandrus germanus (Curculionidae:

Scolytinae)

Christo Nikolovꓹ J. Galko., J. Vakulaꓹ S. Rellꓹ M. Zúbrikꓹ A. Kunca

Forest Research Institute, Forest Protection Service

Xylosandrus germanus (Blandford) - black timber bark beetleColeoptera: Curculionidae, Scolytinae

• Ambrosia beetles in the tribe Xyleborini are among the most successful insect invaders worldwide

• originates from Southeast Asia and has become successfully established within Europe and North America

• Adult female X. germanus tunnel into the heartwood of trees and logs, whereby they cultivate fungal gardens of Ambrosiella grosmanniae

• Ethanol is an important kairomone used during host-location and -selection by X. germanus that acts as a chemical indicator of suitable trees or host logs

Host selection and preference - Xylosandrus germanus

• The known host spectrum of X. germanus currently comprises over 200 shrub and tree species in 51 families

• This includes trees growing in landscapes, woodlands, plantations, ornamentalnurseries, tree fruit orchards, and forested stands, along with recently felled logs, stored timber, and stumps

• Despite a broad host range, host quality plays an important role during host selection

• X. germanus prefer weakened, dying, or stressed trees. Healthy, non-stressed trees are not perceived as a hosts

Host selection and preference

• In Europe, X. germanus is considered a secondary pest that attacks mostly felled tree logs. Most published records are from forests

• While in North America X. germanus is most problematic in tree nurseries and orchards

• Within Europe, X. germanus was first recorded in Germany near Darmstadt on oak and beech in October 1951

• It has been detected in 21 European countries, along with Russia

Spread of Xylosandrus germanus across Europe

The occurrence and spread of X. germanus across Europe

• First detected in 2010 (Juraj Galko)

• Massive increase after extremely warm winter 2013/2014, reports from thewest and central Slovakia

• Leaflet for forest practice

• 2016 – 2018 monitoring on 58 sites, ethanol baited traps

Spread of Xylosandrus germanus in Slovakia

Deviation of average temperatures from the long term mean Northern hemisphere from 1951 – 2000

Author: M. Lapin

Number of beetles captured to pheromone trapsafter the first detection 2010 – 2014, locality Duchonka

Number of X. germanus caught in ethanol-baitedtraps (n = 36) in oak, beech and spruce foreststands (2016)

• XG has invaded the whole country, catches from dozens to thousands

• It also spread vertically into higher altitudes within the country, up to 1000 m a.s.l. (reports from other countries up to 600 m a.s.l., Romania 900 m a.s.l.)

• Dominant species over other ambrosia species

• In Slovakia found on beech, oak, hornbeam, elm, spruce, fir...etc.

• Message for forest practice “Take care about high quality timber, mainlyoak“

Spread of Xylosandrus germanus in Slovakia

Imagines prefer spots without the barkPhoto: Juraj Galko (left), Jiří Hulcr (right)

Fresh attack (white sawdust) of Xylosandrus germanus on oak timber (left) and beech timber (right)Photo: Juraj Galko

After several weeks females expelled noodles of sawdust from the galleries (left); galleries with larvae (right)Photo: Juraj Galko

Ips duplicatus - double-spined bark beetleColeoptera: Curculionidae, Scolytinae

• The distribution of Ips duplicatus ranges from Scandinavia and northeastern Europe to northern Asia

• The known host spectrum of I. duplicatus is Picea spp., Larix spp., Pinus spp.,Pseudotsuga menziesii (Kašák and Foit 2015), Picea omorika (Vakula pers. comm. 2019)

• Two to three generations during one vegetation period

Host selection and preference - Ips duplicatus

• In Europe, I. duplicatus is usually associated with I. typographus on Picea abies

• Due to morphological similarities and similar gallery constructions I. duplicatus isoften not recognized

• Combination of increasing frequency of drought events, warmer temperatures,Norway spruce planting in non-native habitats are considered important predisposing factors triggering the I. duplicatus outbreaks.

Host selection and preference

• Detected in 1996 by Dušan Brutovsky

Spread of Ips duplicatus in Slovakia

• First record - one specimen in 1920 (Roubal 1941)

Spread of Ips duplicatus in Slovakia

• Since 2013 local outbreaks on Picea abies, age over 40 years

• Estimated damages 10 – 50 thousand m3 per year

• It was detected also on Pinus silvestris and this year Picea omorika (Vakulapers. comm. 2019)

• Detected in the mountain areas where was not present previously - deepvalleys

• Higher trap catches along the railway lines

Spread of Ips duplicatus in Slovakia

201389 traps

2017121 traps

Maximum captures to pheromone traps(lure ID-Ecolure, Fytofarm s.r.o.)

Galleries of Ips duplicatusPhoto: Jozef Vakula

Galleries of Ips typographus (blue); Ips duplicatus (red)Photo: Jozef Vakula

Ips typographus (left); Ips duplicatus (right)Photo: Jozef Vakula

• Both species were present probably several years prior to their detection

• Population of both species have been rising rapidly in the last 5 - 10 years

• X. germanus become the dominant species over other ambrosia species in Slovakia only few (4 - 6) years after the first detection

• Shift in altitude

• Able to find a “new“ host species

• Newcomers can invide the whole country in a few years

What have we learned?

2007- Aproceros leucopoda; Zúbrik et al. 2017 Dispersal and larval hosts of the zigzag elm sawfly

Aproceros leucopoda(Hymenoptera) in Slovakia, central Europe. Periodicum biologorum 119 (1): 55-62

2012 - Cydalima perspectalis

2012 - Dryocosmus kuriphilus

2018 - Corytucha arcuata; Zúbrik et al. 2019 First record of Corythucha arcuata in Slovakia – Short

Communication. Plant Protect. Sci., 55: 129-133

List of recently detected non-native species

http://www.los.sk/Knihy