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Datasheet

Phylacteophaga froggatti
(leafblister sawfly)

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Datasheet

Phylacteophaga froggatti (leafblister sawfly)

Summary

  • Last modified
  • 27 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Natural Enemy
  • Preferred Scientific Name
  • Phylacteophaga froggatti
  • Preferred Common Name
  • leafblister sawfly
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Arthropoda
  •       Subphylum: Uniramia
  •         Class: Insecta
  • Summary of Invasiveness
  • The rapid rate of spread of this species throughout New Zealand indicates that this species is indeed invasive. This rapid spread is no doubt due to the insect having multiple generations per year and an abundance of host material. There is also evid...
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Identity

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Preferred Scientific Name

  • Phylacteophaga froggatti Riek

Preferred Common Name

  • leafblister sawfly

Other Scientific Names

  • Phylacteophaga eucalypti froggatti Riek

International Common Names

  • English: eucalyptus leaf mining sawfly; leaf-blister sawfly

Summary of Invasiveness

Top of page The rapid rate of spread of this species throughout New Zealand indicates that this species is indeed invasive. This rapid spread is no doubt due to the insect having multiple generations per year and an abundance of host material. There is also evidence that their flights are wind assisted, and that vehicles and the movement of infested plants assist their spread (Faulds, 1990; Withers, 2001).

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Uniramia
  •                 Class: Insecta
  •                     Order: Hymenoptera
  •                         Family: Pergidae
  •                             Genus: Phylacteophaga
  •                                 Species: Phylacteophaga froggatti

Notes on Taxonomy and Nomenclature

Top of page The genus Phylacteophaga is endemic to Australia and five species are recognized, viz. Phylacteophaga eucalypti, P. froggatti, Phylacteophaga occidens, Phylacteophaga rubida and Phylacteophaga amygdalini. All five species are described and differentiated in a dichotomous key (Mayo et al., 1997).

Description

Top of page Egg

The eggs are flat and discoidal, and have little rigid structure. Egg deposition results in a swelling of the leaf surface, the 'egg gall', which is about 0.5 mm by 0.75 mm. The egg gall is initially the same colour as the leaf, but within 24 to 28 hours it turns light-brown with a red surrounding annulus, about 0.3 mm wide. The leaf tissue beneath the egg becomes pale-brown (Farrell and New, 1980).

Larva

There are four feeding instars in the male and normally five in the female. In both sexes these are followed by a lightly sclerotised non-feeding pre-pupal instar that does not yield a well-defined head capsule on moulting. Head capsule diameters (measured across the widest point) are, in millimetres: I, 0.474 ± 0.026: II, 0.600 ± 0.024; III, 0.743 ± 0.018; IV, 0.931 ± 0.034; and V, 1.082 ± 0.069 (Farrell and New, 1980).

The larvae are orthognathous and dorsoventrally flattened, and normally occupy the mine with their ventral surface uppermost. The legs are small and braced against the leaf cuticle for movement. All instars have conspicuous dark-brown or black plates on a yellowish-white body. The first-instar has only the prosternal plate differentiated. Instars two to five have the prosternal plate enlarged, a small posterior prosternal plate and a ventral plate on the remaining thoracic and abdominal segments. The dorsum of the prothorax is also darkened, the regions around the leg bases are heavily sclerotised, and the anal plate is darkened. The non-feeding pre-pupa lacks all dark sclerotisation, except for a trace of the main prosternal plate, and is further characterised by an unusual change in mandible morphology; the mandible is transformed to bear a single, elongate, median tooth. This structural modification suggests some function in cocoon formation (Farrell and New, 1980).

Pupa

Pupation takes place in the mine, and the ovoid white silk cocoon extends from the cuticle to the mine floor, where it is supported by a silken mat. The cocoons are 7 to 10 mm long and 4 to 8 mm wide (Farrell and New, 1980).

Adult

Female: body length excluding head 5.63 mm (range 4.93-6.40 mm); colour pale red-brown with infuscation mainly over posterior two-thirds of body and as follows: lower posterio-ventral corner of mesepisternum, occasionally mesepimeron and/or metepisternum, metepimeron, metanotum, all metapostnotum or occasionally only band on posterior edge, abdomen except occasionally T8-T10 and part of ovipositor sheaths, occasionally fore tibia and fore tarsus, occasionally mid-tibia and tarsus, hind tibia above, occasionally hind tarsomeres 1 to 4 all or above, and hind apical tarsomere; head width 1.42 mm (range 1.33-1.53 mm); depth 0.59 mm (range 0.54-0.63 mm); eye depth 0.43 mm (range 0.40-0.48 mm); flagellomere 1 length 0.54 mm (range 0.50-0.60 mm); flagellomere 2 length 0.41 mm (range 0.38-0.50 mm); flagellomere 6 length 0.40 mm (range 0.35-0.46 mm); antenna club-like, wider at apex than base, each flagellomere broadening slightly towards apex; tibial spur formula (pre-apical and apical spurs) 1,3,3 1,2,3 or 1,2,2; length of dorsal ovipositor valve 1.087 mm (range 1.000-1.159 mm); crest of dorsal valve sinuous; 37-46 serrulae on crest; dorsal spines with tips tapering to a rounded point with no serrulae; dorsal edge between spines approximately level; length of ventral valve 0.764 mm (range 0.650-0.825 mm); 12 or 13 saw teeth; saw teeth shallow, slightly shorter on proximal than distal edge; cypsellae small and shallow; saw teeth 1 to 8 each with one wide campaniform sensillum slightly distal to its point; saw tooth 8 depth 16.9 µm, (range 14.3-19.0 µm); saw tooth 8 proximal edge length 37.7 µm (range 31.0-42.9 µm); saw tooth 8 distal edge length 44.6 µm (range 35.7-57.1 µm) (Mayo et al., 1997).

Male: as for female except as follows: vertex with infuscate cross- or heart-shaped patch between or partially surrounding ocelli; most or all mesepisternum dark; mesoscutum, mesoscutellum and metapostnotum dark; abdomen dark except occasionally S9; infuscation on all legs darker than in female; fore tibia and tarsomeres 1 to 4 pale; apex of fore tarsomere dark; mid-tibia and tarsomeres 1 to 4 pale; mid-apical tarsomere dark; hind tarsomeres 1 to 4 pale, dark or dark above; flagellomeres 2 to 5 moderately apically produced; aedeagal length 0.325 mm (range 0.313-0.344 mm); aedeagal groove length 0.110 mm (range 0.094-0.131 mm); 'Y'-shaped apodeme reduced to 'V'-shape with short base, length of apodeme 0.207 mm (range 0.200-0.219 mm); gonocondyl length 0.114 mm (range 0.094-0.138 mm) (Mayo et al., 1997).

A cline exists in depth of infuscation on the legs of this species, in that specimens are paler in the northern part of the distribution and darker in the south. Also the tibial spur formula and tibial spur length vary substantially in that the mid and hind pre-apical spurs may be reduced or absent. If they are absent on the hind leg, the pre-apical spur is also absent on the mid leg. In the fore wing, 1-Rs and crossveins may be incomplete or absent, so that cells 1RS, 1R1, 2R1 or 3R1 may be variably open (Mayo et al., 1997).

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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Oceania

AustraliaPresentPresent based on regional distribution.
-New South WalesPresentNative Not invasive Mayo et al., 1997
-QueenslandPresentNative Not invasive Mayo et al., 1997
-South AustraliaPresentNative Not invasive Thumlert and Austin, 1994
-TasmaniaPresentIntroduced Invasive Mayo et al., 1997
-VictoriaPresentNative Not invasive Farrell and New, 1980
-Western AustraliaPresentIntroduced Invasive Curry, 1981
New CaledoniaPresentIntroduced Invasive Naumann, 1991
New ZealandPresentIntroduced Invasive Nuttall, 1985

History of Introduction and Spread

Top of page P. froggatti was first found in New Zealand in 1985, in Auckland. At the time of its discovery it established over a wide area and the damage to trees was quite evident at some localities. By the end of 1986 it had spread throughout Auckland and was present on Waiheke Island, 10 km off-shore. By 1988 it had spread 200 km to the north and 100 km to the south. In 1991 it was found in Picton in the northern South Island; approximately 550 km south of Auckland. By 1996 it had spread a further 350 km to the south (Withers, 2001).

Habitat List

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CategoryHabitatPresenceStatus
Littoral
Coastal areas Present, no further details Harmful (pest or invasive)
Terrestrial-managed
Cultivated / agricultural land Present, no further details Harmful (pest or invasive)
Disturbed areas Present, no further details Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Managed grasslands (grazing systems) Present, no further details Harmful (pest or invasive)
Protected agriculture (e.g. glasshouse production) Present, no further details Harmful (pest or invasive)
Rail / roadsides Present, no further details Harmful (pest or invasive)
Urban / peri-urban areas Present, no further details Harmful (pest or invasive)
Terrestrial-natural
semi-natural/Cold lands / tundra Present, no further details Harmful (pest or invasive)
semi-natural/Deserts Present, no further details Harmful (pest or invasive)
semi-natural/Natural forests Present, no further details Harmful (pest or invasive)
semi-natural/Natural grasslands Present, no further details Harmful (pest or invasive)
semi-natural/Riverbanks Present, no further details Harmful (pest or invasive)
semi-natural/Wetlands Present, no further details Harmful (pest or invasive)

Hosts/Species Affected

Top of page The host range of P. froggatti is primarily confined to Eucalyptus spp., with a limited number of mines being recorded in other genera. These isolated records occur mainly on plants growing in close association with affected eucalypts (Kay, 1986; LM Smith, University of Auckland, New Zealand, personal communication, 1988).

In their revision of the genus Phylacteophaga, Mayo et al. (1997) recorded 14 hosts for P. froggatti, viz. Eucalyptus botryoides, Eucalyptus calophylla [Corymbia calophylla], Eucalyptus camaldulensis, Eucalyptus dunnii, Eucalyptus globulus, Eucalyptus grandis, Eucalyptus lehmannii, Eucalyptus maculata [Corymbia maculata], Eucalyptus mannifera, Eucalyptus nicholii, Eucalyptus robusta, Eucalyptus saligna, Eucalyptus sideroxylon and Eucalyptus tereticornis. They point out that many more hosts are recorded in the literature and note that these require substantiation in the light of changes made to the taxonomy of Phylacteophaga. The hosts listed in this datasheet originate from Curry (1981), Thumlert and Austin (1994), Kay (1986), the New Zealand Forest Research Institute Ltd Forest Health Database and a personal communication with LM Smith (University of Auckland, New Zealand, 1988).

Host Plants and Other Plants Affected

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Plant nameFamilyContext
Agonis flexuosa (willow myrtle)MyrtaceaeOther
Betula (birches)BetulaceaeOther
Corymbia citriodora (lemon-scented gum)MyrtaceaeMain
Corymbia ficifolia (red flowering gum)MyrtaceaeMain
Corymbia maculata (spotted gum)MyrtaceaeMain
Eucalyptus botryoides (southern mahogany)MyrtaceaeMain
Eucalyptus brookeranaMyrtaceaeMain
Eucalyptus calophyllaMyrtaceaeMain
Eucalyptus camaldulensis (red gum)MyrtaceaeMain
Eucalyptus cinereaMyrtaceaeMain
Eucalyptus cladocalyx (sugar gum)MyrtaceaeMain
Eucalyptus crenulataMyrtaceaeMain
Eucalyptus deaneiMyrtaceaeMain
Eucalyptus delegatensis (alpine ash)MyrtaceaeMain
Eucalyptus diversicolorMyrtaceaeMain
Eucalyptus dunnii (Dunn's white gum)MyrtaceaeMain
Eucalyptus fastigata (brown-barrel (USA))MyrtaceaeMain
Eucalyptus globulus (Tasmanian blue gum)MyrtaceaeMain
Eucalyptus gomphocephala (tuart)MyrtaceaeMain
Eucalyptus grandis (saligna gum)MyrtaceaeMain
Eucalyptus kitsonianaMyrtaceaeMain
Eucalyptus lehmannii (bushy yate)MyrtaceaeMain
Eucalyptus leucoxylonMyrtaceaeMain
Eucalyptus macarthurii (Camden woollybutt)MyrtaceaeMain
Eucalyptus macrocarpaMyrtaceaeMain
Eucalyptus maidenii (Maiden's gum)MyrtaceaeMain
Eucalyptus manniferaMyrtaceaeMain
Eucalyptus marginata (jarrah)MyrtaceaeMain
Eucalyptus melliodoraMyrtaceaeMain
Eucalyptus microcorys (Tallowwood)MyrtaceaeMain
Eucalyptus muelleranaMyrtaceaeMain
Eucalyptus nicholii (willow-leaved peppermint)MyrtaceaeMain
Eucalyptus nitens (shining gum)MyrtaceaeMain
Eucalyptus ovata (swamp gum (Australia))MyrtaceaeMain
Eucalyptus paniculata (grey ironbark)MyrtaceaeMain
Eucalyptus perrinianaMyrtaceaeMain
Eucalyptus pilularis (blackbutt)MyrtaceaeMain
Eucalyptus polyanthemos (silver-dollar gum)MyrtaceaeMain
Eucalyptus radiataMyrtaceaeMain
Eucalyptus regnans (mountain ash)MyrtaceaeMain
Eucalyptus resinifera (red mahogany)MyrtaceaeMain
Eucalyptus robusta (swamp mahogany)MyrtaceaeMain
Eucalyptus rudisMyrtaceaeMain
Eucalyptus saligna (Sydney blue gum)MyrtaceaeMain
Eucalyptus sideroxylon (black ironbark)MyrtaceaeMain
Eucalyptus tereticornis (forest red gum)MyrtaceaeMain
Eucalyptus viminalis (ribbon eucalyptus)MyrtaceaeMain
Lophostemon confertus (brush box)MyrtaceaeOther
Quercus palustris (pin oak)FagaceaeOther
Quercus robur (common oak)FagaceaeOther

Growth Stages

Top of page Vegetative growing stage

Symptoms

Top of page The larvae of this sawfly mine inside the leaves of the host plant. The structure of the lower leaf surface remains intact but the upper leaf cells are eaten, leaving just a thin, papery cuticle covering the mine. Individual mines may be 500 mm² in area and several mines may coalesce, destroying much of the leaf. Affected leaves have a brown 'blistered' appearance and may be shed prematurely. Damage is most common on foliage up to 3 m above the ground and small trees can be totally defoliated. In sheltered areas, the damage to large trees can extend high into the canopy (Kay, 1986). At a distance, heavily infested trees look like they have herbicide-spray damage.

List of Symptoms/Signs

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SignLife StagesType
Leaves / abnormal leaf fall
Leaves / abnormal leaf fall
Leaves / internal feeding
Leaves / internal feeding
Leaves / necrotic areas
Leaves / necrotic areas
Whole plant / discoloration
Whole plant / discoloration
Whole plant / plant dead; dieback
Whole plant / plant dead; dieback

Biology and Ecology

Top of page The adults of P. froggatti emerge from their pupal exuviae while still inside their cocoons and escape by chewing a circular emergence hole (LM Smith, University of Auckland, New Zealand, personal communication, 1988). Whilst still within the mine, the wings are frequently fanned to help them dry out (Thumlert and Austin, 1994). The adult cuts an oval emergence hole in the top of the mine and voids a green-grey meconium just before exiting or immediately afterwards. The emergence of the adults from the mines occurs in the early morning and the males tend to emerge before the females. Mating may occur soon afterwards but can also be observed in the field throughout the day (LM Smith, University of Auckland, New Zealand, personal communication, 1988).

In the field the males are often observed perched on the dorsal surface of the leaves with their body held at 45° above the surface, in the vicinity of ovipositing or resting females. Alternatively they can be seen flying in small swarms of five to ten individuals, close to the leaves where mating pairs are perched. Copulation is strophandrous, i.e. the male and female are joined end-to-end with the male genitalia twisted through 180°. In the laboratory mating takes 2 to 3 minutes. During copulation the female stands with her wings folded at rest, whereas the males have their wings spread at about 45° and periodically fan them. After uncoupling, the female immediately moves away and the male remains in place, tapping his abdomen several times on the leaf surface before flying off (Thumlert and Austin, 1994).

In New Zealand, the number of eggs carried by newly emerged females ranges from 21 to 115 (LM Smith, University of Auckland, New Zealand, personal communication, 1988). In Australia, Thumlert and Austin (1994) recorded a range of 57 to 87. In both studies there was a positive correlation with both age and size of the females. P. froggatti reproduces by arrhenotokous parthenogenesis, i.e. fertilised eggs produce females and unfertilised ones produce males.

On landing, female P. froggatti move sideways over the surface of the leaf perpendicular to the mid-vein, with this movement continuing until an oviposition site is chosen. The female saws into the leaf tissue for 5 to 10 seconds, then remains stationary for 3 to 4 minutes while ovipositing. At this time the body and antennae are held at an angle of about 45° to the leaf and to the mid-vein, possibly to position the egg so that the larva hatches in the direction towards the apex of the leaf. Most mines expand in this direction. Once completed the female rubs her abdomen over the position of the egg spot three or four times, possibly to seal the hole, and then moves away. Farrell and New (1980) stated that the egg is deposited between the cuticle and epidermis of the leaf but in New Zealand it has been clearly shown that it is positioned in the upper leaf palisade (LM Smith, University of Auckland, New Zealand, personal communication, 1988). Most eggs are laid within 24 hours of female emergence but a few females can continue to lay a small number of eggs for several days (LM Smith, University of Auckland, New Zealand, personal communication, 1988). The eggs are usually laid on mature foliage (Farrell and New, 1980).

The adults commonly live 2 to 10 days in shade-house enclosures or in the laboratory and a maximum of 15 days has been recorded (LM Smith, University of Auckland, New Zealand, personal communication, 1988). These figures are in agreement with those quoted by Curry (1981) and Farrell and New (1980) which were 7 and 10 days, respectively. Thumlert and Austin (1994) demonstrated that adults provided with water and food lived for nearly twice as long as those that were not. However, when it is remembered that the vast majority of eggs are laid within 24 hours of emergence then longevity of the adults would only be of importance if the species overwintered as adults. Given the length of adult longevity this would not seem to be important. Kay (1986) reported all life stages throughout the year.

At 25°C the eggs hatch in 6 to 8 days, whereas at 15°C they take 12 to 14 days (Farrell and New, 1980). These figures agree with results reported for New Zealand (LM Smith, University of Auckland, New Zealand, personal communication, 1988). The pupal stage lasts approximately 10 to 12 days (Kay, 1986; Thumlert and Austin, 1994). Total development time from oviposition to adult emergence varies from approximately 30 to 100 days depending on the date of oviposition (i.e. temperature during development) (LM Smith, University of Auckland, New Zealand, personal communication, 1988). At approximately 23°C, total development time is 30 to 35 days (Thumlert and Austin, 1994). The slowest development recorded in Auckland, New Zealand was from eggs laid in late April (LM Smith, University of Auckland, New Zealand, personal communication, 1988). There are several generations a year, depending on conditions.

The larvae can successfully complete their development and subsequent pupation in infested leaves that have fallen or been removed from the tree (Kay, 1986).

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Apleurotropis Parasite Larvae
Bracon confusus Parasite New Zealand
Bracon phylacteophagus Parasite Larvae/Pupae
Cirrospilus margiscutellum Parasite Larvae/Pupae
Diaulomorpha Parasite Larvae/Pupae

Notes on Natural Enemies

Top of page Bracon confusus has been recorded as a solitary primary ectoparasitoid of P. froggatti in South Australia and West Australia (Thumlert and Austin, 1994; Loch et al., 2004). Parasitism rates in Western Australia are low (>10%) (Loch et al., 2004). Small numbers of this species were imported into New Zealand along with Bracon phylacteophagus in 1986-1987 and 1987-1988, but none was released. At the time of importation it was not realised that the 'Bracon sp.' imported was actually two species (Austin and Faulds, 1989).

B. phylacteophagus has been recorded as a primary ectoparasitoid of P. froggatti in South Australia (Thumlert and Austin, 1994). After its introduction into New Zealand, the first releases were made in 1988 (Faulds, 1990). By June 1991 it had spread throughout much of the sawfly infested area in New Zealand and in most areas where the parasitoid had been established for more than 1 year, the sawfly populations had collapsed (Faulds, 1991). Today control of the sawfly by this parasitoid is still considered to be very good.

A single specimen of Paraphylax sp. was reared in South Australia by Thumlert and Austin (1994). They say that it was probably the species recorded by Gauld (1984) from P. froggatti in south-eastern Australia.

A species of Brachymeria was reared from several pupae of P. froggatti during 1 week in December 1990 (Thumlert and Austin, 1994).

Elasmus australiensis was reared either as a solitary primary ectoparasitoid or hyperparasitoid of P. froggatti (Thumlert and Austin, 1994).

Apleurotropis spp. have been recorded emerging from P. froggatti mines (Riek, 1955; Farrell and New, 1980). Thumlert and Austin (1994) confirmed that it is a gregarious endoparasitoid of P. froggatti in South Australia.

Chrysonotymia sp. 1 was recorded by Thumlert and Austin (1994) as a gregarious ectoparasitoid of P. froggatti in South Australia. Chrysonotymia sp. 2 was reared by Thumlert and Austin (1994) from mined leaves in South Australia and the association with P. froggatti is only assumed.

Cirrospilus margiscutellum has been recorded as a primary parasitoid of P. froggatti in Western Australia (Loch et al., 2004); as a primary parasitoid of the same host; and as a hyperparasitoid of Bracon spp. in South Australia (Thumlert and Austin, 1994). Undetermined species of Cirrospilus have been recorded from P. froggatti in Victoria (Riek, 1955; Farrell and New, 1980). C. margiscutellum was by far the most commonly reared parasitoid associated with P. froggatti in South Australia and Western Australia (Thumlert and Austin, 1994; Loch et al., 2004). Cirrospilus is a large and taxonomically very difficult genus.

Diaulomorpha sp. is a gregarious ectoparasitoid of P. froggatti larvae and pupae in South Australia (Thumlert and Austin, 1994). An undescribed species belonging to this genus has been recorded from Phylacteophaga mines in Western Australia and elsewhere in Australia (Boucek, 1988).

Thumlert and Austin (1994) reared Eupelmus sp. as a solitary parasitoid of P. froggatti in South Australia. They reared it as a hyperparasitoid from P. froggatti mines.

Curry (1981) lists seven different species of parasitoids, none identified to species, from Western Australia but gives no indication of whether they are primary or hyperparasitoids. They are: Cirrospilus (three species), Elasmus sp., Eupelmus sp., Apanteles sp. and an unnamed genus in the Eulophidae.

Zosterops lateralis (silvereyes) have been implicated (but not proven) as predators of P. froggatti in New Zealand (LM Smith, University of Auckland, New Zealand, personal communication, 1988). Mines are commonly found split open in periods of dry weather and an examination of the split mines reveals no larval remains. This would seem to indicate that the larvae had been removed. Groups of small birds (e.g. Z. lateralis) are often common around P. froggatti infested trees and it would seem that these are likely predators. It is concluded that bird predation was the major mortality factor operating on field populations of P. froggatti (LM Smith, University of Auckland, New Zealand, personal communication, 1988). This study was conducted before B. phylacteophagus (see above) was introduced into New Zealand. Kay (1986) noted that larval mortality of over 80% had been recorded in New Zealand and suggested that rain was probably the main cause. Kay (1986) also stated that general predators, such as birds, undoubtedly help to reduce sawfly numbers. However, other studies using a water sprinkling system in a shade house environment indicated that rain was not the cause of mines splitting (LM Smith, University of Auckland, New Zealand, personal communication, 1988).

Means of Movement and Dispersal

Top of page There is evidence that their flights are wind-assisted, and that vehicles and the movement of infested plants assist their spread (Faulds, 1990; Withers, 2001).

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Land vehicles Yes Yes

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Leaves adults; eggs; larvae; pupae Yes Pest or symptoms usually visible to the naked eye

Impact Summary

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CategoryImpact
Animal/plant collections None
Animal/plant collections None
Animal/plant products None
Animal/plant products None
Biodiversity (generally) None
Biodiversity (generally) None
Crop production None
Crop production None
Environment (generally) None
Environment (generally) None
Fisheries / aquaculture None
Fisheries / aquaculture None
Forestry production Negative
Forestry production Negative
Human health None
Human health None
Livestock production None
Livestock production None
Native fauna None
Native fauna None
Native flora None
Native flora None
Rare/protected species None
Rare/protected species None
Tourism None
Tourism None
Trade/international relations None
Trade/international relations None
Transport/travel None
Transport/travel None

Impact

Top of page In south-eastern Australia heavy infestations of P. froggatti can cause substantial loss of photosynthetic area of the host and this can result in stunted growth or even the death of small trees. This damage is of most concern where large numbers of saplings exist in a confined area such as eucalypt plantations, ornamental eucalypts in parks and gardens and potted trees in outside nurseries (Thumlert and Austin, 1994). Thumlert and Austin (1994) also stated that P. froggatti is rated as one of the most important pests in eucalypt woodlots in south-eastern Australia.

In Western Australia, P. froggatti is considered to be one of the more serious insect pests in the Eucalyptus globulus plantation industry (Abbott, 1993; Loch and Floyd, 2001). Outbreaks are quite common in some areas in Western Australia.

Prior to the introduction of Bracon phylacteophagus into New Zealand, it was predicted that P. froggatti could severely damage commercially important species of Eucalyptus. Consequently this could have serious consequences for the establishment of eucalypt plantations, particularly for those in warm, dry areas that favour insect survival and where newly planted trees may already be under stress (Nuttall, 1985; Kay, 1986).

Economic Impact

Top of page In south-eastern Australia heavy infestations of P. froggatti can cause substantial loss of photosynthetic area of the host and this can result in stunted growth or even the death of small trees. This damage is of most concern where large numbers of saplings exist in a confined area such as eucalypt plantations, ornamental eucalypts in parks and gardens and potted trees in outside nurseries (Thumlert and Austin, 1994). Thumlert and Austin (1994) also stated that P. froggatti is rated as one of the most important pests in eucalypt woodlots in south-eastern Australia.

In Western Australia, P. froggatti is considered to be one of the more serious insect pests in the Eucalyptus globulus plantation industry (Abbott, 1993; Loch and Floyd, 2001). Outbreaks are quite common in some areas in Western Australia.

Prior to the introduction of Bracon phylacteophagus into New Zealand, it was predicted that P. froggatti could severely damage commercially important species of Eucalyptus. Consequently this could have serious consequences for the establishment of eucalypt plantations, particularly for those in warm, dry areas that favour insect survival and where newly planted trees may already be under stress (Nuttall, 1985; Kay, 1986).

Detection and Inspection

Top of page Inspection of the foliage will reveal the presence of the typical 'blister' leaf mines.

Similarities to Other Species/Conditions

Top of page A key to the species of Phylacteophaga is given in Mayo et al. (1997). At a distance, heavily infested trees look like they have herbicide-spray damage.

Prevention and Control

Top of page In nurseries, or for the protection of ornamentals, a foliar spray of insecticide can be used to control the larvae but because some of the sprays used are not very effective against eggs and pupae repeat applications are necessary (Kay, 1986).

Classic biological control using an introduced parasitoid has been very successful in New Zealand (Withers, 2001).

References

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Abbott I, 1993. Insect pest problems of eucalypt plantations in Australia. 6. Western Australia. Australian Forestry, 56:381-384.

Austin AD; Faulds W, 1989. Two new Australian species of Bracon F. (Hymenoptera: Braconidae) parasitic on Phylacteophaga spp. (Hymenoptera: Pergidae). Journal of the Australian Entomological Society, 28(3):207-213

Boucek Z, 1988. Australasian Chalcidoidea (Hymenoptera). A biosystematic revision of genera of fourteen families, with a reclassification of species. Wallingford, Oxon, UK; CAB International, 832 pp.

Curry SJ, 1981. Native wasps hit introduced tree pest. Journal of Agriculture, Western Australia, 22(2):61-62

Farrell GS; New TR, 1980. Some aspects of the biology of the eucalypt-mining sawfly Phylacteophaga froggatti Riek (Hymenoptera: Pergidae). Australian Journal of Zoology, 28(1):83-90

Faulds W, 1990. Introduction into New Zealand of Bracon phylacteophagus, a biocontrol agent of Phylacteophaga froggatti, eucalyptus leaf-mining sawfly. New Zealand Journal of Forestry Science, 20(1):54-64; 8 ref.

Faulds W, 1991. Spread of Bracon phylacteophagus, a biocontrol agent of Phylacteophaga froggatti, and impact on host. New Zealand Journal of Forestry Science, 21(2-3):185-193

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

Kay MK, 1986. Phylacteophaga froggatti Riek (Hymenoptera: Pergidae). Eucalyptus leaf mining sawfly. Forest and Timber Insects in New Zealand, No. 64:8pp.

Loch AD; Floyd RB, 2001. Insect pests of Tasmanian blue gum, Eucalyptus globulus globulus, in south-western Australia: history, current perspective and future prospects. Austral Ecology, 26(5):458-466; many ref.

Loch AD; Matthiessen JN; Floyd RB, 2004. Parasitism and seasonal phenology of leafblister sawfly, Phylacteophaga froggatti (Hymenoptera: Pergidae), in Eucalyptus globulus plantations in south-western Australia. Australian Journal of Entomology, 43:88-93.

Mayo GM; Austin AD; Adams M, 1997. Morphological and electrophoretic taxonomy of the Australian eucalypt leaf-blister sawfly genus Phylacteophaga (Hymenoptera: Pergidae): a potential major pest group of eucalypts worldwide. Bulletin of Entomological Research, 87(6):595-608; 23 ref.

Naumann ID, 1991. Hymenoptera. In: Naumann ID, ed. The insects of Australia, a textbook for students and research workers. Volume 2. Melbourne, Australia: Melbourne University Press, 916-1000.

Nuttall MJ, 1985. New insect pest attacks eucalypts. New Zealand Farmer, 106(19):124-125

Riek EF, 1955. Australian leaf-mining sawflies of the genus Phylacteophaga (Hymenoptera: Tenthredinidae). Aust. J. Zool. 3 (1), (95-8 + 6 photos). 1 ref. [Division of Entomology, Commonwealth Scientific and Industrial Research Organization.].

Thumlert TA; Austin AD, 1994. Biology of Phylacteophaga froggatti Riek (Hymenoptera: Pergidae) and its parasitoids in South Australia. Transactions of the Royal Society of South Australia Incorporated, 118(1/2):99-113

Withers TM, 2001. Colonization of eucalypts in New Zealand by Australian insects. Austral Ecology, 26(5):467-476; many ref.

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