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Uraba lugens
(eucalypt leaf skeletonizer)

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Datasheet

Uraba lugens (eucalypt leaf skeletonizer)

Pictures

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PictureTitleCaptionCopyright
Uraba lugens (eucalypt leaf skeletonizer); adult moth at rest.
TitleAdult
CaptionUraba lugens (eucalypt leaf skeletonizer); adult moth at rest.
Copyright©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); adult moth at rest.
AdultUraba lugens (eucalypt leaf skeletonizer); adult moth at rest.©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae.
TitleLarvae
CaptionUraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae.
Copyright©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae.
LarvaeUraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae.©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae. Note larval feeding damage to underside of leaf.
TitleLarvae
CaptionUraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae. Note larval feeding damage to underside of leaf.
Copyright©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae. Note larval feeding damage to underside of leaf.
LarvaeUraba lugens (eucalypt leaf skeletonizer); small, gregarious larvae. Note larval feeding damage to underside of leaf.©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae.
TitleLarvae
CaptionUraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae.
Copyright©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae.
LarvaeUraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae.©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae. These late instar larvae have the previous instars head capsules 'stacked' above their current head capsule.
TitleLarvae
CaptionUraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae. These late instar larvae have the previous instars head capsules 'stacked' above their current head capsule.
Copyright©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae. These late instar larvae have the previous instars head capsules 'stacked' above their current head capsule.
LarvaeUraba lugens (eucalypt leaf skeletonizer); large, solitary feeding larvae. These late instar larvae have the previous instars head capsules 'stacked' above their current head capsule.©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); pupal cocoon.
TitlePupal cocoon
CaptionUraba lugens (eucalypt leaf skeletonizer); pupal cocoon.
Copyright©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved
Uraba lugens (eucalypt leaf skeletonizer); pupal cocoon.
Pupal cocoonUraba lugens (eucalypt leaf skeletonizer); pupal cocoon.©Scion (New Zealand Forest Research Institute Ltd.) - All Rights Reserved

Identity

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Preferred Scientific Name

  • Uraba lugens Walker, 1863

Preferred Common Name

  • eucalypt leaf skeletonizer

Other Scientific Names

  • Coesa viduella Walker, 1866
  • Roeselia lugens (Walker) Turner, 1943
  • Selca obscura Swinhoe, 1892
  • Toxoloma australe Felder, 1874

International Common Names

  • English: gum leaf skeletoniser; gum leaf, skeletonizer; gum tree, leaf moth, brown; gum, tree moth; gumleaf skeletoniser

EPPO code

  • ROESLU (Roeselia lugens)

Summary of Invasiveness

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U. lugens was first considered a serious pest of natural eucalypt forests in Western Australia in 1983 when the first severe outbreak occurred there (Strelein, 1988). Prior to that it was widely known as a pest of eucalypt forests in eastern Australia (Campbell, 1962; Harris, 1974). As these natural forests are or were managed for timber production, it is considered an economically important pest in its native range. Damage to amenity trees is also a common problem, although few trees are killed by this defoliation (Anonymous, 1979).

U. lugens was recorded as invasive in New Zealand by Crabtree (1997). In its exotic range it has become a significant pest of amenity trees, particularly Lophestemon confertus (Australian brush box), which is commonly planted in some parts of Auckland City (Kriticos et al., 2007).

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Uniramia
  •                 Class: Insecta
  •                     Order: Lepidoptera
  •                         Family: Noctuidae
  •                             Genus: Uraba
  •                                 Species: Uraba lugens

Notes on Taxonomy and Nomenclature

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The endemic Australian moth, gum leaf skeletoniser, was first described by Walker (1863) as Uraba lugens (Arctiidae: Nolinae), with the holotype in the British Museum collection. It was redescribed by Walker (1866) as Coesa viduella. Further synonyms are Toxoloma australe Felder and Selca obscura Swinhoe (Edwards, 1996). Campbell (1962) used the name Roeselia lugens (Walker), following Turner (1944). Various changes have been made to the status of the subfamily Nolinae since Walker’s (1863) description, and it is now considered to be a subfamily within the noctuids (Edwards, 1996), although some authors follow Kitching and Rawlins (1998) in assigning it family rank (e.g. Berry and Mansfield, 2006; Kriticos et al., 2007).

Description

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The small hairy larvae of U. lugens feed gregariously on the upper and lower epidermis, the pallisade tissue and the spongy mesophyll of the leaf but avoid the oil cells and the veins. This feeding habit results in the leaf being ‘skeletonised’, hence the common name of the insect. Larger larvae, from the fifth instar, feed individually and consume the entire leaf blade down to the mid-rib (Cobbinah, 1978). From around the fifth instar, U. lugens larvae retain their moulted head capsules on top of their head, creating a distinctive ‘head dress’. Larvae spin a camouflaged pupal cocoon incorporating their own hairs and fragments of surrounding materials. Adult moths are approximately 10 mm in length with a wingspan of 25 to 30 mm. The forewings are dark grey with several dark wavy lines connecting front and rear wing margins (Anonymous, 1979). The hindwings are pale grey-brown.

Eggs are circular, dorso-ventrally flattened, and measure around 0.25 mm high by 0.50 mm in diameter, Newly laid eggs are green, turning through pale yellow to brown before hatching (Cobbinah, 1978). Newly hatched larvae measure around 2mm in length, with fully grown larvae reaching 25 mm. Instar numbers vary from 8 to 13, with the majority of larvae completing 11 instars in South Australia (Morgan and Cobbinah, 1977; Cobbinah, 1978). Head capsule widths range from 0.23mm in the first instar to 2.66mm in the final instar, and are listed by Allen (1990b) for a range of growing conditions.

Distribution

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U. lugens is found in all states of Australia except the Northern Territory, in areas where the rainfall varies from 500 mm to more than 1500 mm (Campbell, 1962). In Western Australia, it occurs in south-western coastal areas (Kriticos et al., 2007). In Queensland it occurs in coastal areas from Cooktown in the north to the Atherton Tableland, and in southern Queensland (Common, 1990). It is also established in New Zealand, where it was first detected in 1992. As of 2008 it is widespread throughout the Auckland region, and also present in Waikato and Bay of Plenty regions. It is predicted to spread through most areas of New Zealand where eucalypts are grown (Kriticos et al., 2007).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 17 Dec 2021
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Oceania

AustraliaPresent, WidespreadNativeHas a broad distribution in Australia mainly in southern coastal areas.
-New South WalesPresent, WidespreadNativeWidespread in coastal parts of New South Wales. Outbreaks recorded.
-QueenslandPresent, Localized1962NativePresent in localised coastal areas. Outbreaks recorded.
-South AustraliaPresent, Localized2008NativePresent in southern coastal areas around Adelaide. Severe outbreaks recorded.
-TasmaniaPresent, Widespread2008NativeOutbreaks recorded.
-VictoriaPresent, WidespreadNativeOutbreaks recorded.
-Western AustraliaPresent, LocalizedNativePresent in southern coastal regions. Outbreaks recorded.
New ZealandPresent, LocalizedIntroduced1992InvasiveCurrently widespread in the Auckland region, and recorded from Waikato and Bay of Plenty region (J Bain, Scion, Rotorua, New Zealand, personal communication, 2008).

History of Introduction and Spread

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U. lugens was first found outside its native Australia at the Mount Maunganui Golf Course in Tauranga, Bay of Plenty, New Zealand on the 13 June 1997 (Bain et al., 1997). Subsequent to this find it was realised that an earlier record of this species, collected at Mount Maunganui in 1992, had been misidentified (Kriticos et al., 2007). The Mount Maunganui population was thought to be eradicated by 2000 (Ross, 2001). A second population was detected in Auckland in 2001 and eradication was determined unfeasible (Ross, 2003). Since then pheromone trapping surveys have been used to monitor the spread of U. lugens, with the insect widespread in Central and South Auckland by 2004 (Scion, unpublished data. http://gis.scionresearch.com/maful/viewer.htm). By 2006 U. lugens had spread throughout the greater Auckland region, as far north as Pakiri, near Warkworth, and south to Meremere in the Waikato region. An additional pheromone trap catch occurred in 2006 at Katikati in the Bay of Plenty region (Scion, unpublished data. http://gis.scionresearch.com/maful/viewer.htm). In December 2007 egg masses were recorded from Hamilton in the Waikato region, and moths were caught in pheromone traps at Cambridge, also in the Waikato region (J Bain, Scion, Rotorua, New Zealand, personal communication, 2008). No further range extensions have been recorded to the north of the Auckland Region since 2006, despite further pheromone trapping.

Introductions

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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Australia New Zealand 1992 Yes No Bain et al. (1997); Kriticos et al. (2007) First recorded from Mount Maunganui, Tauranga, in 1997, from a specimen collected in 1992. this population was eradicated, but the insect was found again in Auckland 2001.

Risk of Introduction

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U. lugens is likely to continue to spread within New Zealand, with the potential to reach all eucalypt growing areas of the country, which covers all but alpine areas, and central and western parts of the South Island (Kriticos et al., 2007). Agents of further spread are likely to be movement of plant material or wood containing eggs, larvae or pupae from infested areas. Unassisted dispersal is likely to occur at a slow rate, as adult moths are thought to fly a maximum of one km from their pupation site (Morgan and Cobbinah, 1977).

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial ManagedManaged forests, plantations and orchards Principal habitat Harmful (pest or invasive)
Terrestrial ManagedUrban / peri-urban areas Principal habitat Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalNatural forests Principal habitat Harmful (pest or invasive)
Terrestrial Natural / Semi-naturalNatural forests Principal habitat Natural

Hosts/Species Affected

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Morgan and Cobbinah (1977) list 149 Eucalyptus species and one Angophora species found to be oviposition hosts, out of more than 250 species surveyed in a field study in Adelaide, South Australia. Not all of the oviposition hosts proved to be suitable larval hosts. That work was part of a wider study in which over 580 tree species were surveyed (Cobbinah, 1978). Significant defoliation events have occurred in natural forests of Eucalyptus camaldulensis, E. calophylla and E. marginata in mainland Australia (Campbell, 1962; Strelein, 1988; Farr, 2002), and in plantations of E. nitens in Tasmania (Anonymous, 1994) although damage is common on a wide range of eucalypt species. E. nitens and E. fastigata are important commercial plantation and farm forestry species in New Zealand, although commercial impacts of U. lugens on these species have yet to be felt. The iconic native species Metrosideros excelsa (pohutukawa) has been recorded as a host in New Zealand, although this seems to only occur through spill-over feeding from near by eucalypts (Potter at al., 2004) and is not significantly impacting these trees. A number of other new host records have occurred in New Zealand since U. lugens arrived in that country, most notably on a range of deciduous Northern Hemisphere species. The most significant damage on these species has occurred on Betula pendula (silver birch), where some trees have been defoliated (J Bain, Scion, Rotorua, New Zealand, personal communication, 2008).

In New Zealand, U. lugens has been recorded on 58 tree species (J Bain, Scion, Rotorua, New Zealand, personal communication, 2008), mainly from the genus Eucalyptus. It is causing significant damage in New Zealand on Lophestemon confertus, which is commonly planted as a street tree in some parts of Auckland. In a laboratory study of larval suitability of 18 highly valued eucalypt species in New Zealand, Potter and Stephens (2005) found E. nitens, E. nicholii and E. fastigata were most at risk.

Host Plants and Other Plants Affected

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Plant nameFamilyContextReferences
Agonis flexuosa (willow myrtle)LithomyrtusUnknown
Angophora costataLithomyrtusUnknown
Angophora floribundaLithomyrtusUnknown
Angophora hispidaLithomyrtusUnknown
Betula pendula (common silver birch)BetulaceaeUnknown
Callistemon citrinus (lemon bottlebrush)LithomyrtusUnknown
Corymbia citriodora (lemon-scented gum)LithomyrtusUnknown
Corymbia ficifolia (red flowering gum)LithomyrtusUnknown
Corymbia maculata (spotted gum)LithomyrtusUnknown
EucalyptusLithomyrtusUnknown
Eucalyptus acmenoidesLithomyrtusUnknown
Eucalyptus aggregataLithomyrtusUnknown
Eucalyptus blakelyiLithomyrtusUnknown
Eucalyptus bosistoanaLithomyrtusUnknown
Eucalyptus botryoides (southern mahogany)LithomyrtusUnknown
Eucalyptus bridgesianaLithomyrtusUnknown
Eucalyptus brookeranaLithomyrtusUnknown
Eucalyptus caesiaLithomyrtusUnknown
Eucalyptus calophyllaLithomyrtusMain
Eucalyptus camaldulensis (red gum)LithomyrtusMain
Eucalyptus cinereaLithomyrtusUnknown
Eucalyptus cladocalyx (sugar gum)LithomyrtusUnknown
Eucalyptus conferruminataLithomyrtusUnknown
Eucalyptus cosmophyllaLithomyrtusUnknown
Eucalyptus crebra (narrow-leaved red ironbark)LithomyrtusUnknown
Eucalyptus crenulataLithomyrtusUnknown
Eucalyptus dalrympleana (mountain gum)LithomyrtusUnknown
Eucalyptus decipiensLithomyrtusUnknown
Eucalyptus delegatensis (alpine ash)LithomyrtusUnknown
Eucalyptus diversicolorLithomyrtusUnknown
Eucalyptus divesLithomyrtusUnknown
Eucalyptus elataLithomyrtusUnknown
Eucalyptus erythrocorysLithomyrtusUnknown
Eucalyptus eugenioidesLithomyrtusUnknown
Eucalyptus fastigata (brown-barrel (USA))LithomyrtusUnknown
Eucalyptus globulus (Tasmanian blue gum)LithomyrtusUnknown
Eucalyptus grandis (saligna gum)LithomyrtusUnknown
Eucalyptus gunnii (cider gum)LithomyrtusUnknown
Eucalyptus largiflorensLithomyrtusUnknown
Eucalyptus leucoxylonLithomyrtusUnknown
Eucalyptus macarthurii (Camden woollybutt)LithomyrtusUnknown
Eucalyptus macrandraUnknown
Eucalyptus macrocarpaLithomyrtusUnknown
Eucalyptus macrorhynchaLithomyrtusUnknown
Eucalyptus maidenii (Maiden's gum)LithomyrtusUnknown
Eucalyptus majorLithomyrtusUnknown
Eucalyptus marginata (jarrah)LithomyrtusMain
Eucalyptus melanophloia (silver-leaved ironbark)LithomyrtusUnknown
Eucalyptus melliodoraLithomyrtusUnknown
Eucalyptus microcorys (Tallowwood)LithomyrtusUnknown
Eucalyptus moluccanaLithomyrtusUnknown
Eucalyptus muelleranaLithomyrtusUnknown
Eucalyptus multicaulisLithomyrtusUnknown
Eucalyptus nicholii (willow-leaved peppermint)LithomyrtusUnknown
Eucalyptus nitens (shining gum)LithomyrtusMain
Eucalyptus obliqua (messmate stringybark)LithomyrtusUnknown
Eucalyptus patensLithomyrtusUnknown
Eucalyptus pauciflora (cabbage gum)LithomyrtusUnknown
Eucalyptus pilularis (blackbutt)LithomyrtusUnknown
Eucalyptus pulchellaLithomyrtusUnknown
Eucalyptus pulverulentaLithomyrtusUnknown
Eucalyptus radiataLithomyrtusUnknown
Eucalyptus regnans (mountain ash)LithomyrtusUnknown
Eucalyptus robertsoniiLithomyrtusUnknown
Eucalyptus robusta (swamp mahogany)LithomyrtusUnknown
Eucalyptus rubidaLithomyrtusUnknown
Eucalyptus rudisLithomyrtusUnknown
Eucalyptus saligna (Sydney blue gum)LithomyrtusUnknown
Eucalyptus siderophloiaLithomyrtusUnknown
Eucalyptus sideroxylon (black ironbark)LithomyrtusUnknown
Eucalyptus smithiiLithomyrtusUnknown
Eucalyptus stellulataLithomyrtusUnknown
Eucalyptus tereticornis (forest red gum)LithomyrtusUnknown
Eucalyptus viminalis (ribbon eucalyptus)LithomyrtusUnknown
Eucalyptus wandooLithomyrtusUnknown
Fagus sylvatica (common beech)FagaceaeUnknown
Fraxinus excelsior (ash)OleaceaeUnknown
Liquidambar styraciflua (Sweet gum)HamamelidaceaeUnknown
Lophostemon confertus (brush box)LithomyrtusMain
Metrosideros excelsaLithomyrtusUnknown
Populus (poplars)SalicaceaeUnknown
Quercus coccinea (scarlet oak)FagaceaeUnknown
Quercus palustris (pin oak)FagaceaeUnknown
Tristaniopsis laurinaLithomyrtusUnknown

Growth Stages

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Vegetative growing stage

Symptoms

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Early instar larvae skeletonise leaves, which then turn brown, giving the tree a scorched look when damage is heavy. Older larvae feed on the entire leaf blade down to the midrib, which can resemble defoliation.

List of Symptoms/Signs

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SignLife StagesType
Leaves / abnormal leaf fall
Leaves / external feeding

Biology and Ecology

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Reproductive Biology

As is usual with Lepidoptera both males and females are required for reproduction. Potential fecundity ranges from 235-662 (Campbell, 1962). Egg masses contain between 40 and 200 eggs so it is likely that each female lays more than one egg mass. Newly hatched larvae are less than 1 mm in length and are gregarious, skeletonising leaves by feeding on the leaf surface. After around the fifth instar larvae disperse and become solitary, feeding on the entire leaf blade. Mature larvae wander to find a pupation site on the ground or in the tree in bark or leaf litter. A cocoon is spun, incorporating surrounding material for camouflage, in which the larva pupates. Adult emergence and mating takes place during the early hours of darkness (Campbell, 1962).

Thermal requirements and development thresholds (Allen and Keller, 1991):

Life Stage
Lower development threshold oC
Degree days
Egg
6.5
449
Larva
12.2
460
Pupa
9.1
223
  

Physiology and Phenology

U. lugens can have either one (univoltine) or two (bivoltine) generations per year. This seems to be determined to a large extent by climate (Campbell, 1962; Harris, 1974; Farr, 2002) but the position is not clear. Campbell (1962) identified two biological forms of U. lugens: one costal/inland form which is bivoltine, has 11 instars and the eggs are laid in parallel rows one egg diameter apart; and the highland form which is univoltine, with 13 instars and eggs laid in clumps with no intervening spaces (Farr, 2002). In Western Australia, U. lugens has characteristics of both forms (Farr, 2002). In South Australia U. lugens has between 8 and 13 instars (Morgan and Cobbinah, 1977). In its current range in New Zealand U. lugens is bivoltine, with a phenology matching that of U. lugens in Adelaide, South Australia, and eggs laid in parallel rows (Suckling et al., 2005).

Nutrition

U. lugens feeds on a wide variety of eucalypts and related tree species (Morgan and Cobbinah, 1977; Potter and Stephens, 2005), preferring newly mature and mature leaves for oviposition and larval feeding (Morgan and Cobbinah, 1977). Adults do not have functional mouthparts and thus do not feed (Cobbinah, 1978).
 

Climate

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ClimateStatusDescriptionRemark
C - Temperate/Mesothermal climate Preferred Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
15.5-42.9

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Anacis Parasite Arthropods|Pupae not specific Mansfield et al. (2006)
Anastatus Parasite Austin and Allen (1989)
Antrocephalus Parasite Arthropods|Pupae not specific Austin and Allen (1989)
Brachymeria Parasite Arthropods|Pupae not specific Austin and Allen (1989)
Campoplex Parasite Gauld and Fitton (1984)
Campyloneura Parasite Brimblecombe (1962)
Casinaria micra Parasite Arthropods|Larvae not specific Austin and Allen (1989)
Centrodora Parasite not specific Austin and Allen (1989)
Cotesia urabae Parasite Arthropods|Larvae to species Austin and Allen (1989)
Dibrachys Parasite Arthropods|Pupae not specific Berndt and Kriticos (2006)
Dolichogenidea eucalypti Parasite Arthropods|Larvae to species Austin and Allen (1989)
Ecthromorpha intricatoria Parasite Arthropods|Pupae not specific Berndt and Kriticos (2006)
Elasmus australiensis Parasite Austin and Allen (1989)
Eriborus Parasite Arthropods|Larvae not specific Austin and Allen (1989)
Euplectrus Parasite Arthropods|Larvae not specific Austin and Allen (1989)
Eurytoma Parasite Arthropods|Pupae not specific Austin and Allen (1989)
Exorista flaviceps Parasite Arthropods|Larvae not specific Austin and Allen (1989)
Irabatha Parasite Brimblecombe (1962)
Mesochorus Parasite Austin and Allen (1989)
Meteorus pulchricornis Parasite Arthropods|Larvae not specific Mansfield et al. (2006)
Microsmaris goannae Predator Eggs not specific Campbell (1962)
Oechalia schellembergii Predator Arthropods|Larvae not specific Harris (1974)
Paraphylax Parasite Austin and Allen (1989)
Pediobius Parasite Austin and Allen (1989)
Philodromus Predator Arthropods|Larvae not specific Brimblecombe (1962)
Pristomerus Parasite Gauld and Fitton (1984)
Pteromalus Parasite Austin and Allen (1989)
Stiromesostenus Parasite Gauld and Fitton (1984)
Trichogramma Parasite Eggs not specific Austin and Allen (1989)
Winthemia lateralis Parasite Arthropods|Larvae not specific Austin and Allen (1989)
Xanthopimpla rhopaloceros Parasite Arthropods|Pupae not specific Austin and Allen (1989)

Notes on Natural Enemies

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Detailed studies of parasitoids of U. lugens have been conducted in Adelaide, part of the natural range of the species (Austin and Allen, 1989; Allen, 1990a). Twenty-two parasitoid species were identified, including 11 primary parasitoids, 10 hyper-parasitoids, and one facultative hyper-parasitoid. All are thought to be indigenous to Australia. The primary parasitoids were mostly Hymenoptera, belonging to seven different families (Trichogrammatidae, Braconidae, Eulophidae, Ichneumonidae, Chalcididae and Eurytomidae), with two species of Tachinidae (Diptera) (Allen, 1990a). All immature stages of U. lugens were attacked by parasitoids, with parasitoids killing hosts from the third larval instar onwards. Although Allen (1990a) found that parasitism was high in some individual groups of U. lugens (up to 50%), parasitism accounted for only 5-10% of overall mortality at the sites studied. At least two of the primary parasitoids are thought to be specific to U. lugens (Coteisa urabae and Dolichogenidea eucalypti), and these are currently under investigation as possible biological control agents for U. lugens in New Zealand (Berndt et al., 2007).

An additional five hymenopteran parasitoids of U. lugens in Australia have been recorded by other authors (Austin and Allen, 1989). Irabatha sp. (Ichneumonidae) and Campyloneura sp. (Braconidae) were reared from U. lugens in Queensland by Brimblecombe (1962). Gauld (1984) lists three ichneumonids from U. lugens (Stiromesostenus spp., Campoplex sp. and Pristomerus sp.).

Five invertebrate predators have been recorded feeding on U. lugens. The mite Microsmaris goannae (Erythraeidae) feeds on eggs, sucking out the contents, although only a small proportion of eggs are affected (Campbell, 1962). The predatory bugs Oechalia schellenbergii and Cermatulus nasalis nasalis (Hemiptera: Pentatomidae), and the lacewing Chrysopa edwardsi (Neuroptera: Chrysopidae) were found to be significant predators of U. lugens larvae (Cobbinah, 1978). Crab spider Philodromus sp. (Araneae: Thomisidae) (Brimblecombe, 1962), jumping spiders (Araneae: Salticidae) and Nabid bugs (Hemiptera: Nabidae) (Cobbinah,1978) have also been found predating U. lugens. Pathogens recorded attacking U. lugens include Aspergillus parasiticus and A. flavus (Eurotiaceae), Chaetomium sp. (Melanosporaceae) and Beauvaria bassiana (Moniliaceae) (Cobbinah, 1978). Aspergillus has been recorded as an important regulator of U. lugens populations in the Murray Valley region of Australia (Campbell, 1962).

In New Zealand, Mansfield et al. (2005) recorded one larval parasitoid (Meteorus pulchricornis, Hymenoptera: Braconidae) and two pupal parasitoids (Xanthopimpla rhopaloceros and Anacis sp. (Hymenoptera: Ichneumonidae)) attacking U. lugens. Since that study two additional pupal parasitoids (Ecthromorpha intricatoria (Hymenoptera: Ichneumonidae) and Dibrachys sp. (Hymenoptera: Pteromalidae) have been recorded from U. lugens in New Zealand (Berndt and Kriticos, 2006). The current impact of these parasitoids on U. lugens in New Zealand is unknown, although it appears to be minor (LA Berndt, Scion, New Zealand, personal observation, 2008).

Means of Movement and Dispersal

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Adult moths are thought to be poor dispersers (Harris, 1974; Morgan and Cobbinah 1977), however a possible movement of more than 12 km over water was observed by Suckling et al. (2005). The larvae do not disperse widely (Campbell, 1962). Movement of larvae from one host to another does occur but it is uncommon unless there is a shortage of food material and even then the trees must be in very close proximity, if not actually in contact. Larvae can lower themselves to the ground on silken threads and can be blown a short distance by the wind. When on the ground, larvae will move only a short distance to locate another tree.

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Self-propelledAdult moths have limited dispersal ability. Possible movement of >12 km over water. Yes Harris (1974); Morgan and Cobbinah (1977); Suckling et al. (2005)

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Bark arthropods/pupae Yes Pest or symptoms usually visible to the naked eye
Growing medium accompanying plants Pest or symptoms usually visible to the naked eye
Leaves arthropods/eggs; arthropods/larvae Yes Pest or symptoms usually visible to the naked eye
Stems (above ground)/Shoots/Trunks/Branches arthropods/pupae Yes Pest or symptoms usually visible to the naked eye

Impact

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U. lugens was first recorded as an important defoliator of E. camaldulensis by Froggatt (1900). It has caused extensive damage to forests of E. camaldulensis in the Murray Valley region. Since 1919 there have been 11 recorded outbreaks in the area, and up to 40,000 ha of forest defoliated on at least two occasions (Campbell, 1962; Harris, 1974). The 1957-58 outbreak was thought to be associated with the absence of the flooding to which the forests are usually subject to at certain times of the year. It is also a regular problem in Queensland (Brimblecombe, 1962). In 1983 a severe outbreak of U. lugens defoliated thousands of acres of E. marginata and E. calophylla in Western Australia. By 1985/86, 160,000 ha were affected (Strelein, 1988). In the early 1990s there was severe defoliation in large areas of mature dry eucalypt forests in the northeast of Tasmania and in 1992/93 several E. nitens plantations were damaged resulting in various degrees of mortality. At the worst site 20 ha were severely defoliated with 17% mortality. In the same season, a five hectare trial of two-year-old E. nitens was totally defoliated and 2% of the trees died (Anonymous, 1994). 
 

Economic Impact

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No analysis has been made of the economic impacts of this species in Australia, although large areas of managed natural forest have been defoliated (Brimblecombe, 1962; Campbell, 1962; Farr et al., 2004). An impact assessment was conducted for New Zealand (Bain et al., 1997) when U. lugens first arrived in that country. This study concluded that the insect has the potential to become a serious pest of eucalypt species in New Zealand, causing defoliation and loss of growth, with a high negative impact rating for economic and environmental impacts.

Environmental Impact

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In Australia, large areas of native eucalypt forest have been defoliated by this native species at various times (Brimblecombe, 1962; Campbell, 1962; Farr et al., 2004), although the impact on the ecological processes of these habitats is unknown. As a native species in these habitats, any effects of U. lugens on the ecology of these forests could be considered a natural process.

In its invasive range in New Zealand, U. lugens is causing significant damage to amenity trees, but has not so far caused damage to native habitats. Impact assessment studies on a range of New Zealand native species, particularly Metrosideros species in the family Myrtaceae, concluded that damage caused by U. lugens to these species in the field was likely to be rare and insignificant, even though U. lugens larvae are capable of feeding on some species (Potter et al., 2005). It has been recorded as attacking the iconic New Zealand native tree Metrosideros excelsa (pohutukawa), however this was found to only occur where pohutukawa trees grew directly under heavily infested eucalypts, and the damage to these trees so far has been insignificant (Potter et al., 2004).

Social Impact

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The larvae of U. lugens have urticating hairs which can cause painful contact dermatitis (Derraik, 2006). There is little information on the direct impacts of this on human health in Australia or New Zealand, but it is likely to be of concern to children in New Zealand where the species is a recent arrival and there are no other Lepidoptera causing similar reactions to provide prior experience (Derraik, 2006). As U. lugens spreads to plantations in New Zealand it may be of concern to forestry workers.

Risk and Impact Factors

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Invasiveness
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Capable of securing and ingesting a wide range of food
  • Has high reproductive potential
  • Gregarious
Impact outcomes
  • Host damage
  • Negatively impacts forestry
  • Negatively impacts human health
  • Reduced amenity values
Impact mechanisms
  • Causes allergic responses
  • Herbivory/grazing/browsing
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally

Uses

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No human uses relating to economic value, social benefit or environmental benefit known.

Uses List

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Animal feed, fodder, forage

  • Invertebrate food

Detection and Inspection

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U. lugens can be detected by searching leaves. Eggs are laid in batches on the leaf surface, and young larvae feed gregariously adjacent to the egg batch after emergence. Oviposition tends to occur mainly in the lower crow of the tree (Morgan and Cobbinah, 1977). Young larvae skeletonise the leaves, making leaf damage easy to detect. Skeletonised leaves often have characteristic patches of cast skins where larvae have moulted before moving on. After the fifth instar larvae disperse and can be found singly, often in the vicinity of abandoned skeletonised leaves. When close to pupation, larvae wander in search of a suitable site. Camouflaged cocoons are formed in the bark or leaf litter and are very difficult to find. A synthetic pheromone has been developed, and can be used for detection and delimiting surveys (Suckling et al., 2005).

 


 

 

 

 

 

 

 

 

Similarities to Other Species/Conditions

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In New Zealand, U. lugens cannot be mistaken for any other species. There is one other related species, Uraba deplanana Walker, present in Australia (Edwards, 1996).

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

On discovery of U. lugens in New Zealand, the Ministry of Agriculture and Forestry, Biosecurity New Zealand (MAF BNZ, the government organisation with responsibility for new incursions) conducted a delimiting survey and treated infested trees with insecticide in an attempt to eradicate the insect (Ross, 2000). Ongoing surveys in the vicinity were conducted over the following four years (Ross, 2001). Following the second incursion of the pest in Auckland, NZ, in 2001, MAF BNZ followed the same procedure of surveying and insecticide treatment, with the addition of a large scale trapping programme using a synthetic pheromone when the affected area was found to be in the order of 11,000 ha (Thompson, 2003). Due to the large area covered, eradication attempts were not pursued but movement controls were put in place to help slow the spread of the pest (Ross, 2003). Recommendations for the use of selective insecticides for the control of U. lugens have been developed (Mansfield et al., 2006), and stem injection methods are under development for the treatment of individual trees (S Gous, Scion, Rotorua, New Zealand, personal communication, 2008). Biological control is also under development (Berndt et al., 2007).

Gaps in Knowledge/Research Needs

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Little information is available on the economic impacts of U. lugens in its natural range in Australia.

References

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Allen GR, 1990. The phenologies of Cotesia urabae, Dolichogenidea eucalypti (Hymenoptera: Braconidae) and their host Uraba lugens (Lepidoptera: Noctuidae) in the Adelaide region. Australian Journal of Zoology, 38(4):347-362.

Allen GR, 1990. Uraba lugens Walker (Lepidoptera: Noctuidae): larval survival and parasitoid biology in the field in South Australia. Journal of the Australian Entomological Society, 29(4):301-312.

Allen GR, Keller MA, 1991. Uraba lugens (Lepidoptera: Noctuidae) and its parasitoids (Hymenoptera: Braconidae): temperature, host size, and development. Environmental Entomology, 20(2):458-469.

Austin AD, Allen GR, 1989. Parasitoids of Uraba lugens Walker (Lepidoptera: Noctuidae) in South Australia, with description of two new species of Braconidae. Transactions of the Royal Society of South Australia, 113(3-4):169-184.

Australia Ministerial Council on Forestry Fisheries and Aquaculture, 1994. Forest Pest Situation in Australia 1992/93. Report of Research Working Group 8 (Forest Entomology).

Australia, Forestry Commission Tasmania, 1979. Gum leaf skeletoniser moth. Forest Pests and Diseases. Leaflet No. 7.

Bain J, McKenzie H, Crabtree R, 1997. Impact assessment for the gum leaf skeletoniser, Uraba lugens Walker (Lepidoptera: Nolidae) in New Zealand. Contract Report to Ministry of Agriculture and Forestry. New Zealand: New Zealand Forest Research Institute Limited.

Berndt LA, Kriticos DJ, 2006. Uraba lugens (Nolidae) biological control studies 2005/06. Scion, Rotorua. Client report to Ministry of Agriculture and Forestry, Biosecurity New Zealand. Rotorua, New Zealand: Scion, 13 pp.

Berndt LA, Mansfield S, Withers TM, 2007. A method for host range testing of a biological control agent for Uraba lugens. In: New Zealand Plant Protection Hastings, New Zealand: New Zealand Plant Protection Society, 286-290. http://www.nzpps.org/journal.php

Berry JA, Mansfield S, 2006. Hyperparasitoids of the gum leaf skeletoniser, Uraba lugens Walker (Lepidoptera: Nolidae), with implications for the selection of a biological control agent for Uraba lugens in New Zealand. Australian Journal of Entomology, 45(3):215-218. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1440-6055.2006.00532.x

Brimblecombe AR, 1962. Outbreaks of the eucalypt skeletoniser. Australian Journal of Entomology, 19:209-217.

Campbell KG, 1962. The biology of Roeselia lugens (Walk.) the Gum-leaf skeletonizer moth, with particular reference to the Eucalyptus camaldulensis Dehn. (River Red Gum) forests of the Murray Valley Region. Proceedings of the Linnean Society of New South Wales, 87(3):316-38.

Cobbinah JR, 1978. The biology and food preferences of the gum leaf skeletonizer, Uraba lugens (Walk). Adelaide, Australia: University of Adelaide.

Common IFB, 1990. Moths of Australia. Leiden, Netherlands: E. J. Brill, v + 535 pp.

Crabtree R, 1997. The gum leaf skeletoniser, Uraba lugens, at Mt Maunganui. Forest Health News, 65:2-3.

Derraik J, 2006. Erucism in New Zealand: exposure to gum leaf skeletoniser (Uraba lugens) caterpillars in the differential diagnosis of contact dermatitis in the Auckland region. New Zealand Medical Journal, 119(1241):2142-2143. http://www.nzma.org.nz/journal/abstract.php?id=2142

Edwards ED, 1996. Checklist of the Lepidoptera of Australia [ed. by Nielsen ES, Edwards ED, Rangsi TV]., 292, 314. [Monographs on Australian Lepidoptera No. 4.]

Farr JD, 2002. Biology of the gumleaf skeletoniser, Uraba lugens Walker (Lepidoptera: Noctuidae), in the southern jarrah forest of Western Australia. Australian Journal of Entomology, 41(1):60-69.

Farr JD, Swain D, Metcalf F, 2004. Spatial analysis of an outbreak of Uraba lugens (Lepidoptera: Noctuidae) in the southwest of Western Australia: does logging, vegetation type or fire influence outbreaks? Australian Forestry, 67(2):101-110.

Froggatt WW, 1900. Entomological notes on specimens received during 1899. Agricultural Gazette New South Wales, 11(August):647.

Gauld ID, 1984. An introduction to the Ichneumonidae of Australia. London, United Kingdom; British Museum (Natural History), 413 pp.

Harris JA, 1974. The gum leaf skeletoniser Uraba lugens in Victoria. Victoria, Australia. Forestry Technical Papers, No. 21:12-18.

Kitching IJ, Rawlins JE, 1998. Chapter 19: The Noctuoidae. In: Handbook of Zoology Vol. IV Arthropoda: Insecta. Lepidoptera, Moths and Butterflies. Vol. 1: Evolution, Systematics and Biogeography [ed. by Kristensen NP] Berlin & New York, Germany: Walter de Gruyter, 355-402.

Kriticos DJ, Potter KJB, Alexander NS, Gibb AR, Suckling DM, 2007. Using a pheromone lure survey to establish the native and potential distribution of an invasive Lepidopteran, Uraba lugens. Journal of Applied Ecology, 44(4):853-863. http://www.blackwell-synergy.com/loi/jpe

Mansfield S, Kriticos DJ, Potter KJB, Watson MC, 2005. Parasitism of gum leaf skeletoniser (Uraba lugens) in New Zealand. New Zealand Plant Protection, 58:191-196. http://www.hortnet.co.nz/publications/nzpps/

Mansfield S, Withers TM, Gous SF, Potter KJB, Kriticos DJ, Watson MC, Kimberley MO, 2006. Potential of selective insecticides for managing Uraba lugens (Lepidoptera: Nolidae) on eucalypts. Journal of Economic Entomology, 99(3):780-789. http://docserver.esa.catchword.org/deliver/cw/pdf/esa/freepdfs/00220493/v99n3s27.pdf

Morgan FD, Cobbinah JR, 1977. Oviposition and establishment of Uraba lugens (Walker), the gum leaf skeletoniser. Australian Forestry, 40(1):44-55.

Potter K, Kriticos D, Watt M, Watson M, Withers M, Mansfield S, 2005. Uraba lugens (Nolidae) impact assessment studies 2004/05. Client Report No. 38015 to Ministry of Agriculture and Forestry, Biosecurity New Zealand. New Zealand: New Zealand Forest Research Institute Limited, 48 pp.

Potter KJB, Kriticos DJ, Mansfield S, Watson M, Inglis C, Renney L, 2004. Uraba lugens (Nolidae) impact assessment studies 2003/2004. Contract Report for Ministry of Agriculture and Forestry, Biosecurity Authority. New Zealand: New Zealand Forest Research Institute Limited, 17 pp.

Potter KJB, Stephens AEA, 2005. Suitability of valued eucalypt species for the larval development of the gum leaf skeletoniser, Uraba lugens. New Zealand Plant Protection, 58:184-190. http://www.hortnet.co.nz/publications/nzpps/

Ross M, 2000. Gum leaf skeletoniser kept in check. Biosecurity, 23:14.

Ross M, 2001. Gum leaf skeletoniser eradication looks promising. Biosecurity, 32:15.

Ross M, 2003. Gum leaf skeletoniser long-term management approved. Biosecurity, 47:8.

Strelein GJ, 1988. Gum leaf skeletoniser moth, Uraba lugens, in the forests of Western Australia. Australian Forestry, 51(3):197-204

Suckling DM, Gibb AR, Dentener PR, Seldon DS, Clare GK, Jamieson L, Baird D, Kriticos D, El Sayaed A, 2005. Uraba lugens (Lepidoptera: Nolidae) in New Zealand: pheromone trapping for delimitation and phenology. Journal of Economic Entomology, 98:1187-1192.

Thompson P, 2003. Moths galore: a testing time for forest biosecurity. Biosecurity, 43:4-5.

Turner AJ, 1944. A revision of Australian Nolidae (Lepidoptera). Proceedings of the Royal Society of Queensland, 55:13-50.

Walker F, 1863. List of specimens of lepidopterous insects in the collection of the British Museum. British Museum (Natural History) London. Pt.No, 27:144.

Walker F, 1866. List of the specimens of Lepidopterous Insects in the collection of the British Museum., 1534-2040. [Supplement 5.]

Distribution References

Brimblecombe A R, 1962. Outbreaks of the eucalypt skeletoniser. Australian Journal of Entomology. 209-217.

CABI, Undated. Compendium record. Wallingford, UK: CABI

CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

Campbell K G, 1962. The biology of Roeselia lugens (Walk.) the Gum-leaf skeletonizer moth, with particular reference to the Eucalyptus camaldulensis Dehn. (River Red Gum) forests of the Murray Valley Region. Proceedings of the Linnean Society of New South Wales. 87 (3), 316-38.

Common I F B, 1990. Moths of Australia. Leiden, Netherlands: E. J. Brill. v + 535 pp.

Crabtree R, 1997. The gum leaf skeletoniser, Uraba lugens, at Mt Maunganui. Forest Health News. 2-3.

Farr J D, 2002. Biology of the gumleaf skeletoniser, Uraba lugens Walker (Lepidoptera: Noctuidae), in the southern jarrah forest of Western Australia. Australian Journal of Entomology. 41 (1), 60-69. DOI:10.1046/j.1440-6055.2002.00267.x

Harris J A, 1974. The gum leaf skeletoniser Uraba lugens in Victoria. Victoria, Australia. In: Forestry Technical Papers. Victoria, Australia: Forestry Commission of Victoria. 12-18.

Kriticos D J, Potter K J B, Alexander N S, Gibb A R, Suckling D M, 2007. Using a pheromone lure survey to establish the native and potential distribution of an invasive Lepidopteran, Uraba lugens. Journal of Applied Ecology. 44 (4), 853-863. http://www.blackwell-synergy.com/loi/jpe DOI:10.1111/j.1365-2664.2007.01331.x

Mansfield S, Kriticos D J, Potter K J B, Watson M C, 2005. Parasitism of gum leaf skeletoniser (Uraba lugens) in New Zealand. New Zealand Plant Protection. 191-196. http://www.hortnet.co.nz/publications/nzpps/

Mansfield S, Withers T M, Gous S F, Potter K J B, Kriticos D J, Watson M C, Kimberley M O, 2006. Potential of selective insecticides for managing Uraba lugens (Lepidoptera: Nolidae) on eucalypts. Journal of Economic Entomology. 99 (3), 780-789. http://docserver.esa.catchword.org/deliver/cw/pdf/esa/freepdfs/00220493/v99n3s27.pdf DOI:10.1603/0022-0493-99.3.780

Seebens H, Blackburn T M, Dyer E E, Genovesi P, Hulme P E, Jeschke J M, Pagad S, Pyšek P, Winter M, Arianoutsou M, Bacher S, Blasius B, Brundu G, Capinha C, Celesti-Grapow L, Dawson W, Dullinger S, Fuentes N, Jäger H, Kartesz J, Kenis M, Kreft H, Kühn I, Lenzner B, Liebhold A, Mosena A (et al), 2017. No saturation in the accumulation of alien species worldwide. Nature Communications. 8 (2), 14435. http://www.nature.com/articles/ncomms14435

Strelein G J, 1988. Gum leaf skeletoniser moth, Uraba lugens, in the forests of Western Australia. Australian Forestry. 51 (3), 197-204.

Links to Websites

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WebsiteURLComment
Biosecurity New Zealand Pests and Diseases Watchlisthttp://www.biosecurity.govt.nz/pest-and-disease-response/pests-and-diseases-watchlist

Organizations

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New Zealand: Scion (New Zealand Forest Research Institute Ltd), Private Bag 3020, Rotorua, http://www.scionresearch.com

Contributors

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02/05/08 Original text by:

Lisa Berndt, Ensis Forest Biosecurity and Protection, Scion, 49 Sala St, Private Bag 3020, Rotorua, New Zealand

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