Invasive Terrestrial Invertebrates in Victoria

2007·5 MB·English

Biodiversitysymposium
Invasive terrestrial invertebrates in Victoria
Nick Collett1 Greg Lefoe2 and Alan L Yen1
,
'TheUniversityofMelbourne,SchoolofForestandEcosystemScience,
123BrownStreet,Heidelberg,3084.email:[email protected]
'PrimaryIndustriesResearchVictoria,DepartmentofPrimaryIndustries,
40BallartoRoad,Frankston,Victoria3199.email:[email protected]
'PrimaryIndustriesResearchVictoria,DepartmentofPrimaryIndustries,
621 BurwoodHighway,Knoxfield,Victoria3056.email:[email protected]
Abstract
A high number ofexotic invertebrate species has been accidentally or deliberately introduced into
VictoriasinceEuropeansettlement. Theeffectsoftheseintroductionsonnativefloraandfaunahave
ranged from benignthrough todevastating,depending upon the species in question andon the con-
textoftheirintroduction. Exotic speciesaregenerallyeasierto identify, and in thecaseofpotential
futureinvasivespeciesidentifiedthroughsuchprocessesaspestriskanalysiscombinedwithvigilant
quarantine inspection processes, it is possible to anticipate and identify potential paths ofentry to
prevent incursions in the first instance. However, subsequently dealingwith exotic pests that have
successfully established and native invertebrate species that have become pests is a more complex
scenario. This paper discusses some ofthe significant exotic invertebrates to have established in
Victoriaandtheirimpactsontheenvironment,eitherbeneficial,benignoradverse. Impactsofexotic
invertebrates on amenity plantings and forests are examined, as well as issues covering invasive
native invertebrates establishing outside ofeither their normal host or geographic range. Broad
actions toprevent orlimitthe spreadofexotic and native invasive invertebrates are also discussed.
(TheVictorianNaturalist,124(2),2007,87-102)
Introduction
It is estimated that over 500 exotic species been deliberately introduced for primarily
of insects and arachnids have become economic reasons such as the various bio-
established in Australia since European logical control agents, earthworms and
settlement(Thomsonetal. 1987). Thisfig- dung beetles. It is possible that a species
ure includedboth accidental and deliberate introduced for economic purposes ulti-
introductions. No doubt, in the 20 years mately becomes a pest in its own right;
since this estimate was originally made, cane toads, while not invertebrates, are an
the number ofexotic invertebrate species exampleofthis.
that has become established will have The difficulty in defining invasive
increasedsignificantly. species is that not all invasive species are
This paper concerns ‘invasive’ inverte- exotic. There are many examples ofnative
brates in Victoria. One definition ofinva- species that naturally have large popula-
sive invertebrates is ‘a species that is tion boom and bust cycles and become
not native to an ecosystem and whose pests, of which the Australian plague
introduction does or is likely to cause eco- locustChortoicetesterminifera(Walker) is
nomic or environmental harm or harm to a prime example. There are also native
human health’ (Chornesky et al. 2005). species that have been moved out oftheir
This definition links the concept of ‘pest’ natural range and become invasives, while
tohuman interests. some species have become invasives
The distinction between ‘invasive’ and because ofhuman mediated environmental
‘pest’ invertebrates is often blurredand ill- change. Some exotic species have been
defined. Invasive species are often cate- deliberately introduced for beneficial rea-
gorisedas exotic speciesthathavetheabil- sons that may be perceived to have mini-
ity to colonise rapidly and adapt to a par- mal environmental effects (biological con-
ticular environment, and in most cases, trol reasons) or there may be debate about
cause unwanted problems. Exotic species theseeffects(e.g. European HoneyBees).
can be accidental or deliberate introduc- Hence the distinction between exotic,
tions but not all exotic species that are invasive and introduced species is rather
invasive become pests, and some have arbitrary. This paper does not intend to
Vol. 124 (2) 2007 87
Biodiversitysymposium
undertake a comprehensive review ofall Portuguese Millipedes
invasive invertebrates in Victoria. More The Portuguese Millipede Ommatoiulus
thorough treatments can be found in New moreletii (Lucas) (Diplopoda: Julidae) was
(1994). We do not include economic pests first recorded in Australia at Port Lincoln,
ofintroducedagriculturalplants,nordowe South Australia, in 1953 (Baker 1985). It is
consider the occasional outbreaks ofthe now widespread in south-eastern Australia,
native Australian plague locust. We will including Victoria, where it can reach very
primarily deal with invertebrates that may high densities (Baker 1985). Portuguese
have significant detrimental effects on the Millipedes are attracted to light, and
environmentbutwhoseeffectscan be miti- become a nuisance when they invade
gated by actions undertaken by people. homes. They are particularly active in
This includes introduced exotics, intro- autumn when most problems occur.
duced native species, and forest insects Portuguese Millipedes have invaded a
because oftheir potential to expand their range ofhabitats in Australia including
ranges due to changes in land use such as Eucalyptus woodlands, grasslands, and
the expansion ofthe eucalypt plantation domestic gardens. Baker (1985) reported
estate, agroforestryand shelterbelts. that the highest densities occur in newly
invaded areas, with populations subse-
Environmental and amenity aspects of
quently declining as the invasion front
invasiveinvertebrates moves on. Explanations for this decline
The following is a briefresume ofthe bet- include depletion of resources such as
ter known invertebrates that have been food, or the impact ofnatural enemies as
introduced into Victoria. Some exotic native predators adapt to a new prey
invertebrates, such as several species of source. There is, as yet, no evidence that
spiders (Yen 1995), have been accidentally Portuguese Millipedes impact directly on
introduced, but the effects ofthese are not native millipedes although there have been
known. Except for the European Honey only limited studies of interactions (Baker
Bee Apis mellifera Linnaeus, the list does 1985; Griffin and Bull 1995). Baker(1985)
not include species such as dung beetles, suggested Portuguese Millipedes may
earthworms, parasitic wasps and other bio- occupy a previously vacant detritivore
control agents, deliberately introduced for niche in Australia, however, further
beneficial economic and environmental research on the potential impacts of
reasons. Whether these groups have had Portuguese millipedes in natural ecosys-
any adverse effects on the native fauna is tems isneeded.
notknown.
European Wasp Vespula germanica,
Exotics English Wasp Vespulavulgaris
Slugsandsnails The European Wasp Vespula germanica
There are over 60 native slug and snail (F.) (Hymenoptera: Vespidae) is native to
species in southeastern Australia, with 10 Europe, North Africa and temperate Asia,
introduced slug and 12 introduced snail but has subsequently spread to North
species also present (Daniell 1994). The America, New Zealand, South Africa,
main observable environmental effects are South America and Australia (Spradbery
grazing on native plant species by intro- and Maywald 1992). The English Wasp V.
duced slugs and snails. Introduced slugs vulgaris (L.) (Hymenoptera: Vespidae) is
appearto be prevalenton native grasslands closely related to the European Wasp, and
(where there are no known native species inAustraliahas established in Victoriaand
of slugs) with the snail species Theba Tasmania (Lefoe and Ward 2001,
pisana (Muller) also recorded in very high Matthewsetal. 2000). Within Victoriaand
numbers in some coastal duneareas (Smith Tasmania the range of English Wasps is
1967). Introduced snails are not limited to believed to be more restricted than that of
the terrestrial environment, with the exotic European Wasps, although mis-identifica-
snail Potamopyrgus antipodarum (Gray) tion is probably common where their
having colonised some lakes in Victoria ranges overlap. European Wasps are gen-
(Schreiberetal. 1998). erally considered the more serious pest in
88 The Victorian Naturalist
Biodiversitysymposium
Australia because oftheir abundance and cultural industries such as Honey Bees and
widespreaddistribution. soft-fruit industries, especiallygrape grow-
The English Wasp wasfirst discovered in ing and wine making operations. European
AustraliaatMalvern, Victoria, in 1958 and Wasps can also cause serious injury, with
while the initial infestation was destroyed, hospitalisations due to stings increasing in
morewere found in 1960. Despite attempt- Australia (Levick et al. 1997). European
ederadication, English Waspscontinuedto and English Wasps are particularly aggres-
spread in an easterly direction, reaching sive when their nest is threatened, and
the Dandenong Ranges in the early 1970s, accidental disturbance ofwasp nests poses
and West Gippsland by the late 1970s. a considerable threat to humans and other
English Wasps are now also present in animals. In urban areas, the major concern
southeastern Tasmania, including Hobart, is wasp stings, although disruption to out-
where they are thought to have arrived as door activities and the cost ofcontrol add
recentlyas 1995 (Bashford2001). tothe impactofwasps.
European Wasps possibly arrived in Most information on the deleterious
Australia from New Zealand, where they impacts of wasps in natural ecosystems
had initially been accidentally introduced derives from studies conducted in New
and established (Spradbery and Maywald Zealand (Beggs and Wilson 1991, Harris
1992). The firstrecord ofEuropean Wasps andOliver 1993, Beggs and Rees 1999). In
in Australia was in 1954 at Sydney, where natural ecosystems, wasps prey on native
hibernating queens were discovered in a invertebrates, compete with native animals
timber consignment from New Zealand for food, disrupt natural ecosystem
(Chadwick and Nikitin 1969). The first processes, and can pose a health risk to
nests were discovered in 1959 in Hobart, Parks staffand visitors. However there is
Tasmania, and later in New South Wales very little detailed information on the
(1975), Western Australia and Victoria impacts of wasps in Australian ecosys-
(1977) and South Australia (1978) tems. In Tasmania, European Wasps prey
(Spradbery and Maywald 1992). European on the threatened Ptunarra Xenica
Wasps have continued to spread across Oreixenica ptunarra (M Driessen pers.
south and south-eastern Australia where comm. 2001). Bashford(2001) also report-
they have quickly become widespread in ed that the number of calliphorid flies
Tasmania, Victoria and New South Wales caught in Malaise traps at Warra,
(Spradbery and Maywald 1992). Crosland Tasmania, declined as the number of
(1991) estimated unaided queen dispersal Vespula spp. increased. Continued studies
at only 730-815 metres peryear. European at the site may determine whether intro-
Wasps, however, can spread more rapidly duced Vespula wasps have any long term
through accidental human transportation of impact on populations ofcalliphorid flies
hibernating queens (Crosland 1991). In andotherpreyspecies.
SouthAustralia, European Waspsremain a
TheEuropeanHoneyBee, Apismellifera
predominantly urban problem, although
The European Honey Bee, Apis mellifera,
their numbers have increased steadily.
While repeated introductions have has been in Australiafor over 100 years. It
has been an important part ofthe economy
oocuctubrrreeadkinrWeecsotredrendAuisntraPleira,thwiitnh a19la9r0g,e in the provision ofhoney, but there has
European Wasps are not yet considered to been considerable debate about whether it
has been detrimental to native bees and
have successfully established in that state
(Widmer and van Schagen 1995). In other insects, native birds and native
Queensland, reports of European Wasps plants. Paton (1996) concluded that it was
occurred during 1988 and 1991, and the difficult to generalise about the effects of
fainrdstMnaeyswtawlads1f99o2u)n.d in 1992 (Spradbery AV.icmteolrliiafnerNaa,tuarnaldisitn,aNsepweci(a1l99i7s)s,ueScohfwaTrhze
European andEnglish Waspsimpacton a and Hurst (1997), Manning (1997), and
number ofdifferent sectors in the commu- Paton (1997) presented different perspec-
tives on the issue. Paini and Roberts
naintdy.EInnglyiesahrsWoafshpisghcaanbuanfdfaecntcesoEmureopagerain- (2005) provided some preliminary evi-
Vol. 124 (2) 2007 89
Biodiversitysymposium
deuce onA. melliferaaffectingnative bees, 2006). The red imported Fire Ant entered
but Paini (2004) stated that possibly any Victoria in2001 via potted palm treesorig-
adverseeffects arehistorical. In fact, Yates inating from Queensland, where it is under
et al. (2005) give one example in an urban eradication, and in soil on a shipping con-
park where feral Honey Bees may be the tainer from the USA. Both these Victorian
major pollinator of some native plant incursions were subsequently eradicated
species. To complicate the matter further, (John Wainer, pers. comm. 2006).
there could be potential flow-on effects if The major tramp ant species in Victoria
the Honey Bee Mite Varroa destructor is the Argentine Ant. This species was first
(Anderson & Trueman) gets into Australia found in Balwyn in 1939(Clark 1941), and
(Cunninghametal. 2002). it is thought to have spread from this initial
ETnrvaimrpoannmtesntal conditions in Australia cWoalleosn,y tthoecAolCoTnisaendTaWsemsatneiran,ANusetwralSioa.uthIt
hriacvheanrdesduilvteerdseinantthfeauenvaoltuhtaitounndoefrtaakveesrya wsisihdeperriehmoaimrteiclsaynfarnoepmsetstwihnoifcshuuirttbahabenlyeeccnaavnviirteoisentsambeolnuittss-h
range of important ecological functions
(Andersen 1983). A significant threat large foraging trails into houses to seek
food and water. Colonies can range in size
therefore to the Australian environment is from a dozen to many thousands and they
the establishment of exotic ant species.
can establish satellite nests that are highly
Several species have been identified as mobile. However, their pest status spreads
invasive and have colonised different parts beyond the urban environment and they
ofthe world primarily by hitch-hiking on
have an impact in orchards by protecting
nfraemigehdt ttrraansmpporta.ntsT,heosreigainntast,ecomlaliecntliyveliny ahpohniedysdaenwd psrcaoldeusciangaginisntsetchtesirsnuacthuraals
Central and South America, Africa or
South Asia (McGlynn 1999), and have predators and parasitoids. Therearereports
ofArgentineAnts reducingtheabundances
colonised both urban and natural habitats. ofnative ants in California(Holway 1998),
Australia has been colonised by eleven
Hawaii (Cole et al. 1992), South Africa
tramp ant species: the ghost ant Tapinoma (Bond and Slingsby 1984) and Japan
mfoeoltaendocaenpthaTleucmhn(oFambyrricmieusx),altbhiepwehsit(eF-. (anTdouOy’aDmoawedt (al2.00270)03d)e.moRnescternattley,d tRhoawtltehse
Smith), the red imported Fire Ant
Argentine Ant displaced native ant species
Solenopsis invicta (Buren), the Crazy Ant from baits in coastal scrub vegetation on
Paratrechina longicornis (Latreille), the the Mornington Peninsula. This displace-
Yellow Crazy Ant Anoplolepis gracilipes ment has the potential to alter plant com-
(Fr. Smith), the African Big-headed Ant munity composition because some ofthe
Pheidole megacephala (Fabricius), the
displaced native ant species (species of
Argentine AntLinepithemahumile(Mayr),
Pheidole and Rhytidoponera) are impor-
the SingaporeAnt Monomoriumdestructor tant dispersal agents and predators of
(Jerdon), the Pharoah Ant Monomorium
seeds.
pharaonis (Linnaeus), the Tropical Fire
Ant Solenopsis geminata (Fabricius) and Elm Bark Beetle, Elm Leajhopper, Elm
the Little Fire Ant Wasmannia auropunc- LeafBeetle
tata (Roger) (Commonwealth ofAustralia In Australiathe exotic elm tree Ulmus spp.
2006). Whereas specimens ofthe Pharaoh has been widely planted in urban land-
Antwerecollected in StKildain 1938, and scapes, especially in Victoria. The largely
the Singapore Ant in Camberwell (1939) pest-free status of elms in Australia
and Myrtleford (1940), these two species changed in 1974 when the smaller
are primarily tropical and these records European Elm Bark Beetle, Scolytusmulti-
probably reflect more transient than estab- striatus (Marsham) (Coleoptera:
lished populations (John Wainer, pers. Curculionidae), was discovered in
comm. 2006). The African Big-headed Ant Melbourne. While its mode of entry into
was found in Melbourne by Clark (1941) Australia has not been precisely deter-
and more recently by Wainer(pers. comm. mined, it possibly occurred through the
90 The Victorian Naturalist
Biodiversitysymposium
Port ofMelbourne, using dunnage as its dens in Victoria. A native psyllid
vector. Later surveys subsequently found Mycopsylla fici (Tryon) (Hemiptera:
the smaller European Elm Bark Beetle to Homotomidae) causes significant damage
be well established in Victoria (Neumann to Moreton Bay Figs in Victoria (Honan
and Minko 1985) and it has since spread andMcArthur 1998). Feedingbyimmature
into New South Wales, the Australian psyllids causes localised leafnecrosis and
Capital Territory and South Australia early leaf fall. Fallen leaves containing
(Neumann 1987). The smaller European sticky lerps are also a nuisance to pedestri-
Elm BarkBeetle,while widespread, isusu- ans and potentially hazardous when they
allyconsidered aminorpest inthe absence stick to shoes on wet paths. For these rea-
ofthe Dutch elm disease (DED) pathogen. sons chemical control ofpsyllids is some-
However, as a known vector ofthe causal times necessary, although the size ofthe
agents of DED, Ophiostoma ulmi trees, and the protection afforded by the
(Buisman) and O. novo-ulmi Brazier, the sticky lerps has made control difficult.
beetle has the potential to rapidly spread Recent studies (Honan and McArthur
these pathogens should they be introduced 1998; Lefoe 2005) have provided useful
intoAustralia. information to enable tree managers in
In 1986 the Elm Leafhopper, Ribauticma Victoriato monitorpsyllidpopulations and
ulmi Linnaeus (Hemiptera: Cicadellidae) determine whether control is necessary. A
was observed on elms around Melbourne native parasitoid Psyllaephagus sp.
although its mode ofentry is not known. (Hymenoptera: Encyrtidae) is present in
This species ofleafhopper causes cosmetic Melbourne (Honan and McArthur 1998),
damageor ‘speckling’ ofleaves by damag- further highlighting the need to conduct
ing leafmesophyll cells. There is very lit- chemical applications prudently. Although
tle known ofits long-term effects on tree both M. fici and Psyllaephagus sp. are
health and it is usually considered a minor common in central Melbourne, their
pest(Missenetal. 1991). statewidedistribution isnotknown.
The Elm Leaf Beetle, Pyrrhalta luteola
Muller (Coleoptera: Chrysomelidae), a Forestry aspectofinvasive invertebrates
serious pest ofEuropean elms, was first Exoticinvertebrates
discovered on the Mornington Peninsula, Quarantine provides the first line of
Victoria, in 1989 (Kwong and Field 1994). defence against the unwanted introduction
While its mode of introduction is again into Australia of forestry-related insect
unknown, itwaswell establishedbefore its pests, and their subsequent establishment
initial discovery. The elm leaf beetle is in the plantation estate (Lawrence 1963;
now defoliating elms in metropolitan Department of Primary Industries and
Melbourne and much ofregional Victoria Energy 1996). This involves the careful
(Lefoe 1999). Where infestations occur, inspection bytrainedobservers ofall wood
control measures are required to be imple- products and related material capable as
mented immediately to prevent serious acting as a vector for forest insect pests,
defoliation damage occurring. Ifnot ade- and the treatment or immediate destruction
quatelycontrolled. Elm LeafBeetleis like- ofany pests once found. Regular reviews
ly to shorten the lives ofelms in Australia are also conducted to allow for new prod-
and can make them more prone to attack ucts and pathways ofentry that continually
from the smaller European Elm Bark develop (Senate Standing Committee on
Beetle. Natural Resources 1979). Despite continu-
al enforcement of strict quarantine mea-
Nativespecies sures at Australian ports, at least 46
MoretonBayFigpsyllid species of exotic forestry-related insect
The Moreton Bay Fig Ficus macrophylla pests have breeched quarantine barriers
is native to New South Wales and andestablishedin Australia(Table 1).
Queensland, being widespread in coastal An ‘established forest insect pest’ is
scrub and coastal rainforest (Floyd 1989). defined as an exotic insect that has passed
It is a large tree, up to 50 metres high, and through a complete generation or life-
has been planted widely in parks and gar- cycle on or within a native or exotic tree
Vol. 124 (2) 2007 91
Biodiversitysymposium
Table 1.Someexoticforest/forestproductinsectpests,orrelatedorganisms,knowntohaveestab-
lishedinAustralia(DepartmentofPrimary IndustriesandEnergy 19%).
Order/family Genus/species Comments
Acarina(mites,ticks)
Tetranychidae Oligonychusununguis DamagetofoliageofPinusspp.in
(Jacobi)Sprucespidermite Queensland(Wylie 1978)
1soptera(termites. ‘whiteants’)
Kalotermitidae Cryptotermesbrevis Damagetoseasonedexoticandnative
(Walker)WestIndiandrywood softwoodsandlow-densityhardwoods
termite (Gay 1967)establishedinQueensland
during 1930sanddetectedinNSW in
1946(Heather 1971 Eldridgeand
;
Simpson 1987)
C. cynocephalusLight Damagetoseasonedtimber,probably
introducedduring 19lhcentury(Wylie,
DPIQld,pers.comm.)
C. domesticus(Haviland) Damagetoseasonedtimbers,
introducedinearly 1950s(Yuleand
Watson 1976; MillerandPaton 1983)
C. dudleyiBanks Damagetoseasonedtimbers
introducedduringthe 19,hcentury
(Wylie, DPI Qld,pers.comm.,)
Hemiptera(bugs)
Adelgidae Pineuspint(Macquart) DamagetofoliageofPinusspp.on
Pineadelgid marginalsites(TantonandAlder 1977)
Aphidae Elatobiumabietinum DamagetofoliageofPiceaspp.
(Walker)Spruceaphid (Naumann 1993)
Essigellacalifornica(Essig) DamagetofoliageofPinusspp.
MontereyPineaphid (Collettetal.2000)
Euceraphisbetulae DamagetofoliageofBetulaspp.
(Koch)Europeanbirchaphid (Naumann 1993)
Myzocalliscastanicola DamagetofoliageofQuercusspp.
BakerOakaphid (Naumann 1993)
Pemphigusbursarius DamagetofoliageofPopulusspp.
(Linnaeus)Poplargallaphid (Naumann 1993)
Cicadellidae Ribautianaulmi DamagetofoliageofUlmusspp.
(Linnaeus)ElmLeafhopper (Neumann 1991)
Coleoptera(beetles)
Anobiidae Anobiumpunctatum Damagetoseasonedsoftwoods
(DeGeer)Furniturebeetle (French 1968, 1970;CS1RO 1939)
Ernobiusmollis(Linnaeus) Damagetobarkofsoftwood
Pinebarkanobiid (Brimblecombe 1957)
Bostrichidae Dinoderusminutus(Fabricius) WylieandYule(1977)
Bambooborer
Lyctusbrunneus(Stephens) Seriousdamagetoseasonedsapwood
Powderpostbeetle ofmanycucalyptsandbrushwoods
(Rosel 1969;WylieandYule 1977)
L. discedensBlackburn Asabove
Smallpowderpostbeetle
Minthearugicollis(Walker) Damagetoseasonedsapwood
Hairypowderpostbeetle (WylieandYule 1977)
92 The Victorian Naturalist
Biodiversitysymposium
Table1 cont.
Order/family Genus/species Comments
Coleoptera(beetles)
Bostrichidae Rhyzoperthadominica WylieandYule(1977)
(Fabricius)Lessergrainborer
Xylopsocusgibbicollis(Maclcay) Wylieand Peters(1987)
Commonaugerbeetle
Xylothripsreligiosus(Boisduval) WylieandYule(1977)
Northernaugerbeetle
Cerambycidae Aridaeusthoracicus WylieandPeters(1987)
(Donovan)Tigerlongicorn
Hylotrupesbaiulus(Linnaeus) Damagetoseasonedsoftwood
Europeanhouseborer timber(Flowick 1966)
Chrysomelidae Pyrrhaltahiteola(Muller) DamagetofoliageofUlmusspp.
ElmLeafBeetle EstablishedinVictoriainorbefore
1989(Neumann 1991;Kwongand
Field 1994)
Curculionidae
Platypodinae Crossotarsusmniszechi Ambrosiabeetle;
Chapuis WylieandYule(1977)
DiapuspusillimusChapuis Asabove
Walnutpinholeborer
D. quinquespinatusChapuis Asabove
Platypusparallelus(Fabricius) Asabove
Commonambrosiabeetle
Scolytinae1 Eccoptoptemssexspinosus WylieandYule(1977)
(Motschulsky)
Hylastesater(Paykull) Usuallyininnerbarkofdeadpine
Blackpinebarkbeetle material,occasionallykillsyoung
seedlingsonsecondrotationsites
(Minko 1958;Neumann 1987)
Hylurgusligniperda(Fabricius) Asabove
Goldenhairedbarkbeetle
Ipsgrandicollis(Eichhoff) Mostly‘secondary’,butoccasionallya
Fivespinedbarkbeetle ‘primary’treekillerofPinusspp.
Establishedsince 1942(Morgan 1967,
Rimes 1959,NeumannandMorey
1984)
PhloeosinuscupressiHopkins Neumann(1987)
Cypressbarkbeetle
Scolytusmultistriatus(Marsham) Establishedsince 1974in Victoria;
Elm BarkBeetle carrierofDutchElmDisease(Rosel
andFrench 1975;NeumannandMinko
1985)
Xyleborusferrugineus EstablishedinQueenslandbefore
(Fabricius) 1971 (J.K.ing,DPIQld,pers.comm.);
hasattackedgreenlogsofBunyapine
inQueensland;alsologsfromfire-
killedPinusspp.(Wylieetal. 1996)
X.fornucatusEichhoff Boothetal.(1990)
X. indicusEichhoff WylieandYule(1977)
Vol. 124 (2) 2007 93
Biodiversitysymposium
Tabic 1 cont.
Order/familv Genus/species Comments
Coleoptera(beetles)
X.perforans(Wollaston) Asabove
Island pinholeborer
X.saxeseni(Ratzeburg) NeumannandMinko(1985)
Fruit-treepinholeborer
X.similisFerrari Boothelat.(1990)
X. solidusEichhoff Naumann(1993)
Thicksetscolytidborer
X. torquatusEichhoff WylieandYule(1977)
Lepidoptera(butterflies, moths)
Gracillariidae Phyllonoryclermessaniella DamagetofoliageofQuercusspp.
(Zeller)Oakleafminer (Naumann 1993)
Hymenoptera(waspsantsbees,sawflies)
Siricidae SirexnoctilioFabricius Themostdestructivetree-killingpest
Sirexwasp inplantationsofPinusspp. Established
inTasmaniain 1950sandinVictoria
in 1962(GilbertandMiller 1952;
Irvine 1962;Neumannand Minko
1981)
Vespidae Vespulagermanica Importantpestinoperationaland
(Fabricius)Europeanwasp recreation forestry(Dept.Agric.Vic.
1983;Crosland 1991)
V vulgaris(Linnaeus) DetectedinVictoriain 1958;
Englishwasp importantpestinoperationaland
recreationforestry(Dept.Agric.Vic.
1983)
1Sub-familyScolytinae isreportedtocontain92establishedspeciesinAustralia,ofwhich26are
consideredexotic(Brimblecombe 1953).
species or originally uninfested imported exotic pest gains entry. Studies by Wylie
or locally produced wood product, life- and Peters (1987) found that the majority
cycles however, can vary substantially of intercepted wood-boring insect taxa
between insect pest speciesresultingsome- originated in Asia (46.1%) with the next
times in variationsoftimeswhen the insect largest group originating from the
pestentered Australiaandwhen itwas first Australasia/Pacific region (30.4%), with
detected. For example, the Asian Gypsy Asia especially being our most significant
Moth Lymantria dispar (Linnaeus), a trading region. However, care should be
foliage feeder with a one year life-cycle is taken in the interpretation of such trends.
potentially more detectable in its early For example, Australia conducts signifi-
establishment phase than the European cant trade with North America and yet
House Borer (Hylotrupes bajulus interceptions account for only 6.9% of
(Linnaeus)), a less visually apparent wood total interceptions, indicative ofpotentially
boring insect that has a life-cycle of more strict quarantine procedures prior to
between oneandtwentyyears. goods being exported and the types of
The frequency ofexotic insect pest inter- goods exported.
ceptions is generally linked to two factors, In examining the modes of entry by
namely the countries/regions with which which insect pests enter Australia, studies
we conduct the major part ofourtrade and have found that sawn timber and wooden
the pathway (mode ofentry) by which the crates account for 45% and 30% respec-
94 The Victorian Naturalist
Biodiversitysymposium
tively of all interceptions (Wylie and Initial surveillancedatahave shown defoli-
Peters 1987). Using such data is useful in ation to be most pronounced in north-east
directing sometimes scarce resources to Victoria and to a lesser extent in the
monitorthe most likely entry pathways for Ballarat region, coinciding with regions
future insectpestincursions intoAustralia. where mean autumn daily temperatures of
approximately22°C predominate.
Impactsofforestinsectpests The Fivespined Bark Beetle Ips grandi-
in terms offorestry, most invasive exotic collis (Eichhoff) and to a lesser extent the
invertebrates have impacted on exotic Golden-haired Bark Beetle Hylurgus lig-
plantation species such as Pinus radiata niperda (Fabricius) and Black Pine Bark
D.Don althoughafew native insectspecies Beetle Hylastes ater (Paykull) generally
such as Lichenaula spp. (a defoliating attack young, newly established seedlings
moth species) have adapted to exotic tree in plantations where sometimes wide-
species such as P. radiata and, on occa- spread mortality is caused through lethal
sion, cause varying degrees of damage. feeding attacks in the outer cambium lay-
One of the most significant insect pest ers oftrees (Neumann and Morey 1984;
species ofP. radiata is Sirex Wood Wasp Department ofConservation, Forests and
Sirex noctilio Fabricius, first recorded in Lands 1988). Attack is most predominant
Victoria in 1961 where it caused signifi- in summer months when the higher tem-
cant tree mortality before the introduction peratures allow rapid increases in beetle
ofvarious biocontrol and silvicultural con- populations in freshly felled green slash on
trol methods inthe 1970sand 1980s. Sirex, logged sites, before damaging feeding and
through the introduction of phytotoxins, breeding attacks on adjacent young trees
not only kills trees but also renders the and seedlings. Damage by Ips is also
timber subsequently useless for construc- caused to freshly felled logs stored on log-
tion orpulping purposes. In the mid-1970s ging landings where feeding attacks allow
a severe outbreak of Sirex caused exten- the introduction of blue stain fungus
sive tree mortality in the Delatite area ot Diplodia pinea (Desm.) into timber, ren-
north-east Victoria (Neumann etal. 1987), dering it subsequently useless for pulp
while lesser outbreaks have been recorded paper production. Widespread Ips attacks
in south-west Victoria near Rennick in the on seedlings and young four-year-old
mid-1980s and around Shelley in north- Radiata pine trees have been documented
eastVictoriainthe late 1990s. in south west Victoria in the early 1980s
A recently introduced aphid species the with lesser attacks occurring around
Monterey Pine aphid (Essigellacalifornica Myrtleford and Bright (Department of
(Essig)) first observed in north-east Conservation,Forestsand Lands 1988).
Victoria in the late 1990s has established While these examples are by no means
throughout the pine estate where it has comprehensive, they serveto showthevari-
caused significant defoliation damage over ety ofage classes attacked, the range of
a wide area. Symptoms ofdamage include damage (i.e. defoliation and borer damage)
mottled chlorosis ofthe older needles fol- caused and the spread ofseasons and loca-
lowedbyprematureneedle shedwith defo- tionsinwhichdamageiscaused. Somepests
liation most predominate in the upper have an already long historywithin Victoria
crown between March and July (Collett et (i.e. Sirex), with comprehensive information
al. 2000). However, defoliation of the availableontheir‘attackprofiles’. However,
lower crown can also be associated with some ofthe more recent introductions such
very severe levels ofaphid attack (Collett as the Monterey Pine aphid require longer
et al. 2000). Defoliation is predominantly term research coupledwith ongoing surveil-
observed in pine stands greaterthan 15 yrs lance to develop pest profiles so as to assist
ofage. However, ithas also been observed in making more informed longerterm man-
occurring in stands of all age classes agementdecisions.
(Collett et al. 2000). Such defoliation has
been shown to result in substantial reduc- Invasivenativepestinvertebrates
tions in incremental growth and associated In terms of invasive native invertebrates
declines in timber yields (May 2004). within a forestry setting in Victoria, this
Vol. 124 (2) 2007 95
Biodiversitysymposium
concept requires a more detailed definition their range of native biocontrol agents.
of what situations we consider a native Examples of this scenario include
insect to be termed a "pest’ species. In E. grandis (Hill) plantings at Mildura,
native forests it is difficult to define ade- which have drawn in populations of
quately outbreaks of native invertebrate Autumn gum moth Mnesampela privata
species such as the Red Gum psyllid (Guenee) intothe region(Bashford 1998).
Cardiaspina retator (Taylor), Gumleaf
Skeletoniser Uraba lugens Walker and Future threats posed by exotic pest
Spurlegged Phasmatid Didymuria vio- incursions
lescens (Leach) as ‘pest outbreaks’. Such The list ofexotic insect pest species likely
'outbreaks’ are well documented in the lit- to cause considerable damage to the plan-
erature throughout Victoria in the past 50- tation industry in Victoria is potentially
60 years (Neumann and Marks 1976; enormous. Until an exotic pest species has
1990; Neumann 1978; Collett 2001; Harris entered and established, there is no certain
1972; Elliott et al.1998) and it could be way to determine the exact threat it poses
suggested that such outbreaks are cyclical to both native and exotic plantation tree
and form part ofthe normal ‘ebband flow’ species. However, in order to plan for the
of invertebrate activity within native eventuality ofsuch exotic insect pest incur-
forests. Only when these ‘outbreaks’ sions occurring, rigorous interrogation of
impact on economic activities such as har- available information is conducted todeter-
vesting and logging or on the aesthetics of mine the country oforigin of potentially
forest areas with parks and reserves could dangerous insect pests, including such
we possiblyconsiderthem ‘pestoutbreaks’ information astheirhosttree species range,
in the traditional sense. When examining life-cycle and optimal environmental con-
the ‘invasive’ aspects of such outbreaks, ditions for development both in their coun-
there is no substantial documented evi- try oforigin and Australia. This informa-
dence that any ofthese ‘pest species’ gen- tion is incorporated into pest profiles
erally move beyond their expected geo- known as Pest Risk Assessments (PRAs)
graphic range when in outbreak mode to which can be specific to individual pest
native forest areas outside this range. Only species or generically written to cover a
when these insect species are found within range of insects posing a similar risk. A
native plantations may it be reasonable PRA includes all known available informa-
therefore to treat them as ‘invasive pest’ tion on a pest species as well as contin-
species. An example ofthis scenario is U. gency plans for dealing with an incursion
lugens in north central Victoria, which has and potential outbreak of the pest in
caused occasional defoliation to E. camal- Australia. The lists ofpotential pest species
dulensis (Dehnh.) plantations (Collett pers. and associated PRAs varies constantly as
comm. 2006), with the original populations new information is gathered, examined and
having originated within native red gum updatesprovidedaccordingly.
forests in the region. In these situations, While many insect pest species pose a
the possibilityofparallelsbeingmadewith considerable threat to plantations, a small
exotic insect incursions in exotic softwood subset has been selected as species with
plantations could be made, although the the greatest potential toestablish and cause
potential to control such outbreaks, espe- significant economic and environmental
cially using methods such as biological damage. This list is shown in Table 2 and
control, wouldbesubstantiallydiminished. wascompiled bythe Australian Quarantine
Ofconcent, however, is the potential for and Inspection Service(AQIS) in consulta-
eucalypt plantations using tree species tion with state forestry authorities
planted well out of their native range to (Commonwealth ofAustralia2001). Ofthe
‘draw in’ native insect pest species, which species listed, the majority are borer
in turn may divert either on to local native specieswith the potential toenterAustralia
plant species or alternative native planta- cryptically within timber products, and
tion species. The situation may also arise consequently are sometimes difficult to
whereby the spread of these ‘invasive’ assess fully and subsequently treat. Other
native pests may not be accompanied by pests such as the potentially highly
96 The Victorian Naturalist