Australian Stonefruit Grower Magazine Issue 2 August 2016 | Page 23

Feature

(SWD). This tiny, but extremely damaging, pest was
first found in California in 2008. Although peaches and
nectarines are not a preferred host, it can infest them if
populations are high and/or other hosts are not available.
Although the Import Risk Assessment for USA stonefruit
was finalised in 2010, Australia had already introduced
emergency quarantine measures in response to the risks
associated with any import of SWD hosts, including
stonefruit. Access was put on hold until a quarantine
treatment was developed and proven effective against SWD
– this proved to be fumigation with methyl bromide (MB).
Plums gained access in early 2015, with apricots finally
gaining access in July this year. However, don’t expect
to see Californian apricots on shelves any time soon –
apricots are generally considered too fragile to tolerate
Initial field examination
of peaches
Initial field
examination
harvested into white
lugs.
of peaches
harvested
Photo: Mountain View
into Fruit
white lugs. Photo:
Mountain View Fruit
months, so minimising the time between harvest
and cooling is essential to maintaining fruit quality.

quarantine treatment and shipping. However, there is
interest in plumcots; these plum + apricot hybrids can
now be imported, as both parents have been shown to be
disinfested by the same treatment.

The complexity of quarantine

Peaches and nectarines can be imported into Australia

Hydrocooling is the dominant cooling method used. Fruit

from California, Oregon, Washington and Idaho. Plums

are then graded and packed similarly to large Australian

can only be imported from certain Californian counties.

operations.

Access is based on area freedom from fruit flies (except

Exports to Australia

cherry fruit fly) as well as a two-hour fumigation with 48g/
m3 MB at pulp temperatures >13.9°C and chamber loading

Californian stonefruit first gained entry to the Australian

not more than 38%. This treatment is more severe than that

market on 19 July, 2013. As with Australian nectarines

conducted for other export markets, reflecting Australia’s

finally getting access to China, this was the culmination

intense concern about this pest.

of many years of negotiations, pest risk assessments
and quarantine protocol negotiation.
Importers who had already been
waiting for years pounced on
the opportunity, and the first
USA peaches and nectarines
arrived in the markets within
a fortnight.
Access would have

Fumigation can severely damage some varieties, causing
a characteristic skin browning known as “fumo-burn”. In
addition, fruit has to be warmed for fumigation and
then re-cooled afterwards, a process that can
increases ripening and can result in less even
quality on arrival.
Initial exports into the Australian market
were somewhat hit-and-miss, as some fruit
– white peaches, for example – were in poor

occurred sooner had it not
been for Drosophila suzukii,
or spotted wing drosophila
summerfruit.com.au

Fumigation damage (fume-burn)
on a white peach.
Photo: J. Ekman

august 2016 | Australian Stonefruit Grower

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