Risk analysis of Halyomorpha halys - Biosecurity New Zealand

and the consequent import health standard for specific country and commodity
combinations. Post-harvest export production systems typically include steps such as
washing, brushing and visual inspection, although this can vary depending on the
commodity. Furthermore the architecture of different commodities can determine the
procedures used, for example oranges are much easier to wash and inspect than
grapes; therefore, grapes may require additional treatments to comply with the
relevant import health standard.
Egg masses have occasionally been observed on fruit (grapes and peaches, (Leskey,
2011)); however, this is considered a rare occurrence and it is expected that the export
production system for fresh fruit will remove most of these egg masses from the
commodity.
Fresh produce and nursery stock that is host material for H. halys is imported into
New Zealand from countries with recorded populations of H. halys. These
consignments are comprised of asparagus, apple, citrus fruit, nashi pear and stonefruit
imported from the USA, South Korea, China and Taiwan (QuanCargo 2011).
The only time that H. halys is likely to be associated with imported fresh produce and
cut flowers is during the northern hemisphere spring to autumn period when
reproductive adults, egg masses, nymphal instars and young adults are present on host
plants. Therefore, neither the fresh produce nor cut flowers pathway is likely to
provide opportunity for entry during the overwintering period when individuals are
not present on host plants.
In addition to commercial practices to reduce the abundance of pests on commodities
all fresh produce and cut flowers imported into New Zealand are covered by an
import health standard specific to that commodity and country combination. This
import health standard sets out measures to ensure that the commodity is free of
biosecurity contaminants; these management measures will go some way to mitigate
the likelihood of entry. Samples are taken from each lot and examined for the
presence of contamination in order to verify that the required management has been
undertaken (MAFBNZ 2011b). The records of live Pentatomids of all life stages
being detected during verification at the New Zealand border indicate that the specific
measures are not always managing the risks of similar species.
Given that:
Halyomorpha halys may be associated with fresh produce and cut flowers of
host plants imported from relevant countries;
host material is imported from relevant countries;
adults and nymphs are easily disturbed and it is assumed they would leave the
commodity during routine handling for harvest and packing;
Halyomorpha halys will only be associated with host plant commodities
during the northern hemisphere spring to autumn period;
fresh produce and cut flowers are covered by import health standards which
contain requirements which will reduce the likelihood of entry;
given the different production systems, management measures, countries of
origin, and architecture of different commodities the likelihood of entry will
differ within this general pathway and is likely to range from negligible to
moderate;
Ministry for Primary Industries Risk Analysis: Halyomorpha halys 21