Pests and diseases of forestry in New Zealand
UNWANTED PESTS ARRIVE IN COMFORT
From Biosecurity Magazine - Issue 79, November 2007
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| Figure 1: Typical couch
upholstered, upholstery removed, and timber frame exposed |
Recent reports by MAF's Investigation
and Diagnostic Centre (IDC) have shown that wooden furniture imported
from Asia (particularly China) poses a significant biosecurity risk to
New Zealand. The Biosecurity Monitoring Group has taken apart a sample
of imported lounge suites from China and Malaysia to find out how many
pests are getting an armchair ride across the border. They found that,
while there was plenty of evidence of poor-quality construction
materials and hitchhiking pests, voluntary fumigation of the furniture
by importers is keeping the pest risk low.
Since 1988 there have been 83 detections of exotic organisms associated
with imported furniture entering New Zealand of which 41 percent came
from China, Indonesia and Thailand. Over half of these detections
occurred post-border after biosecurity clearance had been issued, with
many being detected by members of the public.
Signs of infestation on internal sections
On several occasions, IDC investigators discovered wood-borer tracks
and holes covered up with putty. Further investigations noted that some
Chinese furniture manufacturers put good quality (unblemished) wood on
visible surfaces, and poor quality (insect damaged and occasionally
bark covered) timber in internal sections of the furniture. This
practice led the IDC to believe that unseen internal timber used in the
manufacture of upholstered furniture is likely to be of poor quality
and therefore of higher risk of being contaminated.
The high numbers of imported couches (about 40,000 couches from China
and Malaysia in 2005), coupled with the potential for poor-quality,
infested materials led to a concern that upholstered furniture could be
an important pathway for pests and pathogens that posed a risk to New
Zealand's forestry sector. As a result, a joint project was initiated
between the Biosecurity Monitoring Group (BMG) and IDC Incursion
Investigation, Plants and Environment team to determine the level of
contaminated wood used in imported Chinese and Malaysian upholstered
furniture.
Survey initiated – poor quality materials in furniture
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Figure
4: Frequency of timber types (identified to Family) found in couches
(n=50) from China and Malaysia
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A total of 37 lounge suites, comprising 51 individual items, were
purchased from retailers who routinely import couches from China and
Malaysia. The BMG survey team systematically inspected each item,
beginning with the complete piece of furniture and progressively
removing the outer covering and padding (Figure 1). All contaminants
found were collected for identification. Small samples of each type of
timber were also collected from each item of furniture for wood
identification.
The first thing the surveyors found was that the construction materials
used were of poor quality. A number of couches were constructed from
undressed and dirty timber (even the occasional tree branch – see
Figure 2), and some were heavily contaminated with borer holes and bark
(Figure 3).
Of the 51 couches inspected, 39 (77 percent) were contaminated with
insects, pathogens, bark, plant material or had evidence of previous
insect damage (Table 1). Thirty-two couches had borer holes, and 24 couches had more
than one type of contaminant.
Multiple timber types
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| Figure 2: Part of a tree branch
used in the construction of a couch |
At least 65 different types of wood (from 25 families) were used in the
construction of the couches sampled (Figure 4). Most couches had more
than one timber type used in their construction (Donaldson 2006). The
presence of multiple timber types is of concern because by increasing
the number of potential host woods imported, it increases the chance
that a couch will introduce a pest or pathogen to New Zealand.
Furthermore, several of the wood types identified were closely related
to New Zealand natives and wood of economic importance. These may carry
pests/pathogens with the potential to be of biosecurity concern.
Currently, importers commonly choose to fumigate all couch imports to
accelerate the clearance process. As a result, all but one of the
insects found in the couches was dead (38 in total). The only living
specimen found was a species of Cardiastethus that may have entered the
couch at the retailer's premises.
Overall, 11 couches were infested with fungi, and 10 of these were
infested with more than one species. Fourteen specimens of viable fungi
were identified from the wood samples. However, of the six fungal
specimens identified to species, all were saprophytes already present
in New Zealand.
Biosecurity risk low if furniture fumigated
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| Figure 3: Insect tunnelling and
larvae under bark from a sample of timber taken from a couch |
A high proportion of upholstered furniture imported into New Zealand
from China and Malaysia appears to be infested with potential pests and
pathogens. This may be a result of the low-grade materials used in the
manufacture of the couches. However, the overall risk of upholstered
furniture to biosecurity is low due to effective intervention by
importers: importers voluntarily fumigate couches either overseas or in
New Zealand.
In the absence of these voluntary interventions, the importation of
upholstered furniture poses a potential biosecurity risk to New
Zealand. Ongoing management of this pathway should focus on maintaining
communication with industry to ensure that current interventions are
maintained.
References
L Donaldson, 2006, Report on timber species from Chinese couches, Scion
report prepared for the Ministry of Agriculture and Forestry.
Thompson G, Froud K, Pearson H, Tohovaka S, Whyte C and McCarthy B,
2007, Contaminants of upholstered furniture from China and Malaysia,
June 2006, Biosecurity New Zealand, BMG 06-07/04.
Authors
Glen Thompson, Analysis and Profiling Group, MAF Biosecurity New
Zealand, phone 09 909 3514, glen.thompson@maf.govt.nz
Karyn Froud, Investigation and Diagnostic Centres, MAF Biosecurity New
Zealand, phone 09 909 5729, karyn.froud@maf.govt.nz
Sharon Tohovaka, Cargo Clearance Group, MAF Biosecurity New Zealand,
phone 09 909 3516, sharon.tohovaka@maf.govt.nz
Victoria Allison, Analysis and Profiling Group, MAF Biosecurity New
Zealand, phone 09 909 3510, victoria.allison@maf.govt.nz
