Journal of the Department of Agriculture, Western , Series 4

Volume 22 Number 2 1981 Article 13

1-1-1981

Native wasps hit introduced tree pest

S J. Curry

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Recommended Citation Curry, S J. (1981) "Native wasps hit introduced tree pest," Journal of the Department of Agriculture, , Series 4: Vol. 22 : No. 2 , Article 13. Available at: https://researchlibrary.agric.wa.gov.au/journal_agriculture4/vol22/iss2/13

This article is brought to you for free and open access by Research Library. It has been accepted for inclusion in Journal of the Department of Agriculture, Western Australia, Series 4 by an authorized administrator of Research Library. For more information, please contact [email protected]. Native wasps hit introd · ce tree est

However, the larvae of blister • The leaf blister and its larval stages in are leaf miners and feed the leaf. within the upper surface of eucalypt . The eggs are laid either singly or in rows near the leaf midrib and the resulting larvae produce rounded blotch mines, which may eventually cover the whole leaf surface, giving it a scorched appearance. When fully grown, each larva pupates in a silk cocoon within the mine, which then takes on an oval blister-like appearance. The adult wasp cuts a hole in the blister to emerge. Development from egg to adult takes about six weeks and the adult wasp lives about a week in the laboratory.

P. froggatti attacks more than 15 • Forestry entomologist S. J. Curry examines eucalypt species in Western sawfly damage. Australia, including eight introduced eastern species and seven native by S. J. Curry species. The most heavily attacked of these are grandis, E. robusta, E. camaldulensis and E. The first leaf blister sawfly damage in rudis. The heaviest damage is Western Australia was noticed in the inflicted on the lower leaves up to metropolitan area in the spring about six metres from the ground, of 1978. Young eucalypts planted in but some older E. rudis have suffered carparks, recreation areas and street serious damage up to 10 metres. verges were mainly affected. The pest spread through the metropolitan area during 1979, when it attacked larger Control trees up to JO m high. By 1980 young trees were under attack in several Systemic insecticidal (dimethoate) country towns including Albany, foliage sprays and trunk injections Bunbury, Busse/ton, Katanning and can control the pest. As some degree Geraldton. In some of these towns at of wasp activity appears to continue least, the trees were found to have throughout the year in the originated in Perth tree nurseries. metropolitan area, entomologists explored the possibility of The sawfly species was identified as introducing wasp parasites from the Phy/acteophaga froggatti which is Eastern States in 1979. At least two not native to Western Australia but is such parasites have been recorded in common in Victoria, New South New South Wales (Riek 1955 and Wales and Queensland. A native Moore 1966) and two in Victoria Western Australian species, P. (Farrell and New 1980). These occidens, is of infrequent occurrence included a Braconid: Bracon sp. and and has caused no widespread a Eulophid Cirrospilus sp. They are damage. Fortunately, Western ectoparasites (external) of late instar Australia has native parasites which (development stage) sawfly larvae, attack the pest. They are 'moving in' and of the pupae. However, at that already. time, suitable numbers of parasites were not available due to low levels of sawfly populations in the east. Life cycle and damage Nevertheless, during March 1980 a Leaf blister sawflies (Phylacteophaga number of parasitic wasps emerged spp.) are small wasps belonging to from sawfly infested leaves from a the family Pergidae. This family also northern metropolitan suburb and includes the gregarious sawflies, investigations showed that about 10 whose larvae, commonly called per cent parasitisation had occurred. 'spitfires' feed externally on eucalypt Small numbers continued to emerge leaves. throughout 1980.

61 From February 1981, a further in 1958, but still remains unidentified increase in parasite numbers occurred by the world authority. Table 1. in infested leaves from the same The one Eastern States' species• northern suburb, bringing the Cirrospilus-has been recorded as a Western Australianspp. parasitation level to about 20 per parasite of P. froggatti in eastern cent. Parasites also have emerged Australia. from infested foliage collected in *Eucalyptus rudis (Flooded gum) other suburbs, particularly in the If the parasite population continues * (River gum) to increase and spread in Western Eucalyptus gomphocephala (Tuart) areas south of the Swan River, and in Eucalyptus diversicolor (Karri) country towns including Albany and Australia there seems every possiblity Eucalyptusficifolia (Red flooded gum) Busselton. of a balance being achieved between Eucalyptus lehmannii (Bald Island parasite and sawfly populations, so mar lock) So far seven different species of that excessive damage to young (Jarrah) Hymenopterous parasites ha\.{e been eucalypts may be Jess likely in future. identified from Western Australia by With the continuing popularity of EasternStates spp. CSIRO's Division of Entomology, tree planting both in town and Canberra. Only one of these, found country, sawfly infestations are · " (Rose gum) so far only in small numbers, also bound to continue, so it may be *Eucalyptus robusta (Swamp mahogany) occurs in eastern Australia. The rest better policy in the long term to * Eucalyptus camaldulensis (River red gum) appear to be native to this State. eucalypt species which are least (Tasmanian blue They include the following genera:- susceptible to attack. Susceptible gum) species are listed in Table 1. Eucalyptus botryoides (Southern Cirrospilus-three species (Family: mahogany) Eucalyptus melliodora (Yellow box) Eulophidae)-includes the one References Eucalyptus citriodora (Lemon scented Eastern States species Rick E. F. (1955): Australian leaf-mining gum) sawflies of the genus Phylacteophaga Eucalyptus c/adoca/yx (Sugar gum) Elasmus sp. (Family: Elasmidae) (Hymenoptera: Tenthedinidae) Aust. J. Zool. Eupelmus sp. (Family: Eupelmidae) 3, 95-8. Apanteles sp. (Family: Braconidae) Moore K. M. (1966): Observations on some *Most susceptible. Unnamed genus (Family: Eulophidae) Australian forest insects, 22. Notes on some -one sp. Australian leaf-miners, Aust. Zool. 13,303-49. Farrell G. S. and New T. R. (1980). Some The last species listed is the most aspects of the biology of the Eucalypt-mining saw-fly, Phylacteophaga froggatii' Rick • Left: Blisters showing small emergence hole numerous from all areas. It was (Hymenoptera: Pergidae). Aust. J. Zool. of wasp parasite, and large emergence hole of recorded previously from Pemberton 28,83-90. adult sawfly. Right: The adult parasite.

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