forest health news No. 182, March 2008 ISSN 1175-9755

SPREAD OF PAROPSIS CHARYBDIS PARASITOIDS INTO THE SOUTH ISLAND Paropsis charybdis (Chrysomelidae), an introduced Australian species, is the most important defoliator of Eucalyptus spp. in New Zealand.The parasitoid wasp Enoggera nassaui (Pteromalidae) was introduced to New Zealand as a biological control agent of P. charybdis in 1987 and 2000. In 2001 two additional parasitoids, both new self-introduced species, were reared from P. charybdis eggs collected in the central North Island (FH News 117, April 2002). The first, Neopolycystus insectifurax (Pteromalidae) is a primary egg parasitoid of P. charybdis like E. nassaui. This wasp was expected to complement control provided by E. nassaui, and an unsuccessful attempt had even been made to introduce it in 1987. It was later discovered that the specimens released in 1987 were not N. insectifurax but an unidentified species. The appearance of N. insectifurax in 2001 stimulated renewed confidence in the biological control ofP. charybdis. Unfortunately, the second self-introduced species recovered in 2001 was identified as an obligate hyperparasitoid ofE. nassaui. Baeoanusia albifunicle (Encyrtidae) had the potential to disrupt the control of P. charybdis by parasitising eggs already parasitised by E. nassaui, effectively preventing E. nassaui from successfully reproducing. It was soon realised, however, that N. insectifurax was immune to the Upper: Known hyperparasitoid and might have some capacity to compensate for a distribution of B. albifunicle. hyperparasitoid-driven decline in E. nassaui. As it became evident that the dynamics of the biological control of P. charybdis were Right: Known changing in the central North Island where all three parasitoids distribution of were present (see FH News150, April 2005), plans were made to N. insectifurax assess the distribution of each species to determine what other areas might be similarly affected. Field surveys were conducted in the South Island between December 2007 and January 2008, and P. charybdis eggs were Enoggera nassaui is still a significant control agent ofP. charybdis sought and assessed for parasitism by E. nassaui, N. insectifurax, in New Zealand, but N. insectifurax and B. albifunicle appear to be and B. albifunicle. Several North Island regions where parasitoids altering the seasonal patterns of this control and the new situation had not been officially recorded were also surveyed, and the Scion has yet to reach equilibrium. If B. albifunicle is able to reduce the Forest Health Database was searched for distribution records of abundance of E. nassaui it may exacerbate the poor level of control all three species. Field survey and database results were combined of the first spring generation of P. charybdis which sometimes to produce distribution maps for each species. occurs in the central North Island. As the hyperparasitoid is also Enoggera nassaui was recovered from most sites surveyed in the present in the some parts of the South Island, similar patterns South Island. It has now been found in 20 of the 29 regions of may also occur there. Fortunately N. insectifurax seems to have New Zealand (as defined by Crosby et al. 1998) from Northland established well on both North and South Islands and there is to Southland. Regions where it has not been recorded represent evidence it might be beginning to dominate over E. nassaui later those which have not been surveyed specifically for its presence in summer, and so control of the second annual generation of (Taranaki, Rangitikei, Wanganui, Wairarapa, Fiordland, and P. charybdis may be maintained. Stewart Island) and three regions (Hawke’s Bay, South Canterbury, and Mackenzie) where P. charybdis eggs could not be located Crosby, T.K.; Dugdale, J.S.; Watt, J.C. 1998: Area codes for recording during the current survey. specimen localities in the New Zealand subregion. New Zealand Journal of Zoology 25: 175–183. Both N. insectifurax and B. albifunicle were recorded for the first Tara Murray time in Northland, on the east coast of the North Island, and in the South Island. This represents a wide latitudinal distribution and THE MONTEREY PINE APHID IN NEW ZEALAND it is unlikely that either species is particularly limited by climate. That said, however, unlike E. nassaui, neither N. insectifurax The Monterey pine aphid, Essigella californica, has been the nor B. albifunicle have been found in surveys of Southland subject of recent studies in New Zealand and Australia. It is native as recently as March 2008, so it is possible there is a climatic to western North America and Mexico where it feeds on Pinaceae, limitation here. primarily Pinus, and occasionally on Pseudotsuga species. It was

Newsletter of the Scion Forest Biosecurity and Protection Unit, and the Forest Health Reference Laboratory (incorporating the Forest Research Mycological Herbarium (NZFRI-M), the Forest Research Culture Collection (NZFS), and the National Forest Insect Collection (FRNZ). Edited by John Bain, New Zealand Forest Research Institute Ltd, Private Bag 3020, Rotorua. Web site < http://www.scionresearch.com/biosecurity > Forest Health News 182, March 2008 first recorded outside the USA in 1989 in France, where it caused In Australia, E. californica has been associated with upper crown localised damage and needle yellowing. The aphid has since yellowing and premature needle shed in P. radiata forests, but a become established in Spain, southern Brazil, Australia, and New causal relationship has been difficult to demonstrate. Defoliation Zealand. It was first detected in Australia and New Zealand in typically occurs between early autumn and late winter. Damage has 1998 and found to be widespread in these countries. been most severe in south-eastern Australia, particularly in stands older than 15 years. Defoliation associated with E. californica has In New Zealand, the been estimated to have reduced productivity of P. radiata plantings impact of E. californica in this area by A$21 million per year. is largely unknown. Large numbers of this aphid To investigate further the potential impact of this pest in New have been recorded on Zealand, Scion has been monitoring E. californica abundance on P. particular Pinus radiata radiata at two climatically contrasting forests — Kaingaroa Forest trees in some years but in the Bay of Plenty and McLeans Island in Canterbury — for the there are few records of past 2 years. The beat method was used to sample aphid numbers, damage on these trees. which peak in autumn from March to May. Significantly more A climate model of E. E. californica were recorded in autumn 2006 than 2007, and at the californica had predicted Canterbury site in both years. No leaf yellowing associated with E. excessive rainfall might californica was recorded at either site, suggesting that it may not be limit aphid numbers, and a problem for New Zealand forest growers. Monitoring has begun the comparatively high this autumn, with unexpectedly low numbers recorded so far. numbers of E. californica The higher numbers of aphids collected at the Canterbury site, recorded at favourable which is much drier and has higher average summer and autumn sites in Australia suggest temperatures than the Bay of Plenty forest, validate the climate Yellowing associated with aphid damage the New Zealand climate is model predictions. in Australia. generally less favourable Michelle Watson Photo courtesy of Ian W. Smith, University for the aphid. of Melbourne.

NEW RECORDS

New host record for New Zealand – Insect: Lindingaspis rossi Thorp, 06/03/2008; Ident: J Bain, 07/03/2008; Comments: This beetle, (Diaspididae); Region: Hawke’s Bay; Host: Heliohebe hulkeana; Coll: which is the vector of Dutch elm disease, was first recorded in New B Rogan, 22/02/2008; Ident: J Bain, 04/02/2008; Comments: This scale Zealand in 1990 and previously was known from Auckland, Waikato, insect is sub-cosmopolitan on the tropics and sub-tropics. It was first and Bay of Plenty. Note that Dutch elm disease is still confined to the found in New Zealand in 1895 and has been recorded from a wide range Auckland area. of native and exotic plants here. New distribution record for New Zealand – Insect: Scolytus multistriatus New host record for New Zealand – Insect: Didymus intutus (Curculionidae: Scolytinae); Region: Hawke’s Bay; Host: Ulmus procera; (Curculionidae); Region: Auckland; Host: Olearia albida; Coll: C Inglis, Coll: B Rogan, 19/03/2008; Ident: J Bain, 25/03/2008; Comments: This 27/02/2008; Ident: J Bain, 04/03/2008; Comments: This native weevil beetle, which is the vector of Dutch elm disease, was first recorded in New has been reared from the dead wood of various species including Olearia Zealand in 1990 and previously was known from Auckland, Waikato, furfuracea. It is particularly common on coastal vegetation. Bay of Plenty, and Taupo. Note that Dutch elm disease is still confined New host record for New Zealand – Insect: Strepsicrates ejectana to the Auckland area (Tortricidae); Region: Wellington; Host: Agonis linearifolia; Coll: New distribution record for New Zealand – Insect: Acrocercops B Rogan, 12/02/2008; Ident: J Bain, 05/03/2008; Comments: This native laciniella (Gracillariidae); Region: North Canterbury; Host: Eucalyptus moth, which is also found in Australia, Philippines, Marianus, Fiji, and nitens; Coll: P Bradbury, 12/03/2008; Ident: J Bain, 18/03/2008; French Polynesia, has been recorded from a variety of myrtaceous and Comments: This Australian species was first found in New Zealand in ericaceous hosts. 1999 and has been recorded from about 50 species of Eucalyptus and New host record for New Zealand – Insect: Pseudococcus longispinus Lophostemon and Angophora spp. It is widespread in the North Island (Pseudococcidae); Region: Auckland; Host: Euonymus japonicus; Coll: and has previously been recorded from Nelson, Marlborough Sounds, C Inglis, 27/02/2008; Ident: R Henderson, 14/03/2008; Comments: This Marlborough, and Mid Canterbury in the South Island. cosmopolitan mealy bug was first recorded in New Zealand in 1890. It New distribution record for New Zealand – Insect: Dicranosterna has been recorded from a wide range of hosts. semipunctata; Region: Taupo; Host: Acacia sp.; Coll: J Bartram, New host record for New Zealand – Insect: Strepsicrates macropetana 18/03/2008; Ident: J Bain, 19/03/2008; Comments: This Australian beetle (Tortricidae); Region: Hawke’s Bay; Host: Eucalyptus cosmophylla; was first found in New Zealand in 1996 in Auckland. It has previously Coll: B Rogan, 17/03/2008; Ident: J Bain, 26/03/2008; Comments: This been recorded from Northland, Auckland, Coromandel, Bay of Plenty, Australian species was first found in New Zealand in 1921 and is common and Waikato. on Eucalyptus spp. It has also been recorded from Melaleuca fulgens. New distribution record for New Zealand – Fungus: Pucciniastrum New host record for New Zealand – Insect: Strepsicrates macropetana pustulatum; Region: Hawke’s Bay; Host: Fuchsia magellanica; Coll: (Tortricidae); Region: Hawke’s Bay; Host: Eucalyptus paniculata; B Rogan, 17/03/2008; Ident: A Hopkins, 20/03/2008; Comments: This Coll: B Rogan, 18/03/2008; Ident: J Bain, 28/03/2008; Comments: rust fungus has previously been recorded from Auckland, Waikato, See above. Taranaki, Wellington, Mid Canterbury, Stewart Island, and the Chatham New distribution record for New Zealand – Insect: Nambouria Islands. It has been recorded from Fuchsia spp., Clarkia amoena, xanthops (Pteromalidae); Region: Marlborough Sounds; Host: Eucalyptus Epilobium alsinoides, E. linnaeoides, and Zauschneria californica (all viminalis; Coll: B Doherty, 28/02/2008; Ident: J Bain, 05/03/2008; these are in the family Onagraceae). Comments: This Australian species was first found in New Zealand in New host record and new life stage for New Zealand – Fungus: 1999 and has been recorded from nearly 20 species of Eucalyptus here. It Pseudovalsa longipes; Region: Mid Canterbury; Host: Quercus cerris is common on E. nicholii and E. cinerea and has previously been recorded f. laciniata; Coll: B Doherty, 25/02/2008; Ident: M Dick, 13/03/2008; from Northland, Auckland, Waikato, Coromandel, Bay of Plenty, Gisborne, Comments: The anamorph (asexual stage) was reported in December Hawke’s Bay, and Mid Canterbury. 2005 on Quercus robur and Castanea sativa but the teleomorph (sexual New distribution record for New Zealand – Insect: Scolytus multistriatus stage) was not found on those specimens. It is found on the bark of small (Curculionidae: Scolytinae); Region: Taupo; Host: not applicable; Coll: G branches. John Bain 2 Printed by Scion Digital Print Centre, Rotorua (07-343-5711)