No. 121, August 2002 ISSN 1175-9755
• QUARANTINE TREATMENT OF EXPORT LOGS Frontline believes that the solution for New Zealand lies in It is common knowledge that the need to move logs around a more integrated approach involving the identification and the world increases the chances of spreading unwanted reduction of risks, and the restriction of methyl bromide pests and diseases. Despite this, biosecurity threats application to specific biological requirements instead of as associated with the log trade are generally poorly a blanket fumigation specification. Research into new quantified and still not well understood. Some countries, fumigants and fumigation techniques will be undertaken in such as the United States, through the Animal and Plant parallel with the above programme. Resolving this issue is Health Inspection Service (APHIS), have undertaken risk likely to take time, and will involve dialogue with trading assessments to estimate the apparent levels of threat posed partners, Government agencies such as the Ministry of by specific organisms that might be imported with Agriculture and Forestry (MAF), as well as the forestry softwood logs from New Zealand, Chile and Russia sector. However, failure to recognize and address the (FHNews 118:2). However, most countries simply deal problem may have serious implications for the meeting of with this issue by applying an arbitrary broad-spectrum environmental standards. The future use of methyl treatment against a generalised undefined hazard. This bromide, even for quarantine purposes, is far from assured. approach is often not well related to the risks it is designed 1anti-sapstain chemicals applied to export logs may also have biosecurity significance to address, and besides posing specific problems for log (Gordon Hosking, Forest Research) exporters, also has wider environmental implications. Logs sent abroad from New Zealand are generally debarked, • WESTERN GALL RUST MEETS TOD RAMSFIELD fumigated, or subjected to both types of treatment, in order Western gall rust, caused by the rust fungus to reduce the biosecurity risk for recipient countries1. The Endocronartium harknessii, is another disease of Pinus most common fumigant applied is methyl bromide, which radiata we prefer to keep out of New Zealand. One of is cheap and effective against a wide range of organisms. several pine stem rusts, this native of western North Unfortunately, methyl bromide is also an ozone depleting America induces rounded galls that deform the branches gas that has been banned for non-quarantine use in many and stems of trees of a number of 2- and 3-needle pine countries. New Zealand is one of the biggest users of species. Infected trees become malformed and, when methyl bromide, particularly in the forest industry, young, suffer breakage and death, all of which could have a primarily for the treatment of log and timber exports. serious economic impact on forestry in this country, should the fungus ever become established. Western gall rust is a particular threat because, unlike many of the other pine stem rusts, it can spread directly from pine to pine, without the need for an alternate host plant. Early identification of this pathogen is vital for successful eradication, but unhappily E. harknessii cannot be isolated into culture from the host tissues. While it is readily identified from the form and germination pattern of its powdery spores, these are only produced on the galls seasonally, and not until at least two years after infection. This hampers the quick diagnosis of unknown galls, as was demonstrated several years ago when rounded stem swellings in young P. radiata stands caused concern in Tasmania (FHNews 89:1).
The requirements for treating logs vary considerably between importing countries. For instance, while Japan requires an application of just 32g/m3 of methyl bromide, logs sent to China must be subjected to a rate of 120g/m3. Some reduction in methyl bromide treatment has been achieved by employing phosphine for hold-stowed logs, which can be fumigated in this way while in transit. However, top-stowed logs must still be fumigated before loading, and the use of methyl bromide has grown alarmingly with the increasing log trade with China. Frontline Biosecurity, a joint venture company involving Forest Research, Windsor Engineering, Biosecurity Services, and Genera, is exploring strategies to reduce methyl bromide use in the forestry sector. While the search for alternative fumigants to methyl bromide has a long history, no cheap effective candidates have emerged. Ravaged radiata 1: western gall rust in young trees in California Newsletter of the Forest Health and Biosecurity Project, 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 Ian Hood, New Zealand Forest Research Institute Ltd, Private Bag 3020, Rotorua.
One solution to the diagnosis of the pathogen in non- large, fresh samples more likely to remain in good sporulating galls is to use a molecular method that will condition in water. Despite the difficulties, please continue identify the rust mycelium within the woody gall tissue. A to send in samples for diagnosis. Only in this way can we protocol to do this using a species-specific molecular gradually increase our knowledge of this important pest marker is being developed by Tod Ramsfield, who recently group. joined the Forest Health team at Forest Research as (from material supplied by Roger Crabtree, Forest Research) molecular plant pathologist. The early stages of this project involved the extraction of DNA from rust aeciospores • ICPP 2003 collected in British Columbia. Tod also met Dr Det Vogler of the Institute of Forest Genetics, USDA Forest Service, New Zealand is to host a major international plant who has worked on the detection of fungi in woody tissues, pathology event early next year. Between 2-7 February th including that of E. harknessii in P. radiata in California. 2003, the 8 International Congress of Plant Pathology will be held at the Christchurch Convention Centre, incorporating the 14th Biennial Australasian Plant Pathology Conference. Well over a thousand delegates from all round the world will hold discussions and workshops, and present papers and posters on topics as diverse as “improving plant disease management for Asian farmers” and the “integration of genetics and genomics for understanding control of plant defense responses”. Forestry will feature in sessions on 3 February (forest diseases in the Asia-Pacific region), 5 February morning (management of forest diseases), 5 February afternoon (management of risks posed by exotic forest pathogens). These will include presentations from New Zealand, Australia, Asia, North America, and Europe. Forest pathology field tours will be held to view and discuss examples of forest diseases, comprising a one day trip in Canterbury on 8 February, and a two day central North Island tour centred on Rotorua on 10-11 February. We will be approaching forest companies to seek participation and assistance in these tours. For further information on the congress, visit: