Farm Forestry New Zealand
PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
Phylacteophaga froggatti - still moving southwards
Scion is the leading provider of forest-related knowledge in New Zealand
Formerly known as the Forest Research Institute, Scion has been a leader in research relating to forest health for over 50 years. The Rotorua-based Crown Research Institute continues to provide science that will protect all forests from damage caused by insect pests, pathogens and weeds. The information presented below arises from these research activities.
From Forest Health News 203, March 2010.
The Australian eucalyptus leaf mining sawfly was first found in New Zealand near Auckland Airport in March 1985. By the end of 1986 it was present over an area extending from Pukekohe to Waiwera with isolated occurrences in Glen Massey and Waingaro, Whangamata and Waiheke Island. By 1989 it was recorded from the Bay of Plenty, Hawke’s Bay and Wanganui and by 1990 from Gisborne and Taranaki.
Although it was first recorded from the South Island in 1991 (Marlborough Sounds) it was not found in Wellington until 1996 and was not detected in the Wairarapa until 2007. By 1998 it was found as far south as South Canterbury and in 2002 it turned up in Buller. This relatively 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. Transport in vehicles and on infested plants may very well account for it being found in the Marlborough Sounds five years before it was found in Wellington. When present in an area the damage caused by the sawfly is quite obvious, particularly to experienced forest health surveillance officers who were responsible for nearly all of the new records.
In December 2009 the sawfly was found for the first time in Dunedin so it evidently took about 7 years to spread there from South Canterbury. What are the odds of it arriving in Invercargill in the next couple of months?
As the common name would imply the usual hosts of P. froggatti are species of Eucalyptus but there are a few records of it from non-eucalypt hosts particularly when they have been growing in close proximity to eucalypts. These unusual hosts include, Quercus, Betula and Agonis. Favoured hosts are Eucalyptus botryoides, E. cinerea, E. nitens and E. saligna. It has also been recorded from Lophostemon confertus in both Australia and New Zealand.
Phylacteophaga froggatti is native to Queensland, New South Wales, Victoria and South Australia but has become established in Tasmania, Western Australia and New Caledonia as well as New Zealand.
As early as 1988 an Australian parasitoid of P. froggatti, Bracon phylacteophagus, was imported from Australia and released in New Zealand. This established and spread very quickly and was soon exerting very good control of the leaf miner. This is still the case today.
Stephanie Sopow
This information is intended for general interest only. It is not intended to be a substitute for specific specialist advice on any matter and should not be relied on for that purpose. Scion will not be liable for any direct, indirect, incidental, special, consequential or exemplary damages, loss of profits, or any other intangible losses that result from using the information provided on this site.
(Scion is the trading name of the New Zealand Forest Research Institute Limited.)
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