Biosecurity officials are promising to take tough action against cargo vessels believed to be infested with brown marmorated stink bug during the upcoming risk season.

Stink bugs can cause physical damage to winegrapes, including bunch rots and yield loss, and are also known to cause wine taint if they end up in ferments.

Steve Gilbert, director of Border Clearance Services, Biosecurity New Zealand, said arriving vessels arriving to New Zealand will be dealt with on a case-by-case basis.

“However, if our officers ultimately determine a ship is infested with stink bug, it will be prevented from discharging its cargo and directed to leave New Zealand.

“We have also introduced a very low threshold for determining contamination. If we find a single bug, we will thoroughly investigate whether the entire vessel is contaminated.”

Gilbert said Biosecurity New Zealand will also be increasing surveillance and inspection of arriving vessels and cargo from countries with known stink bug populations.

“This is about ensuring the dangerous pest does not get a chance to establish in New Zealand,” he added.

Biosecurity rules have changed for this season, making it compulsory for certain types of cargo to be treated before arrival to remove the risk of hitchhiking stink bugs.

“As a result, Biosecurity New Zealand requires cargo such as uncontainerised vehicles and machinery to be assessed as compliant before we allow discharge from the vessel. We will also no longer direct contaminated vessels to undergo fogging with insecticide in New Zealand.”

Biosecurity New Zealand introduced fogging as an emergency treatment option in February following a spike in stink bug detections in vehicle carriers from Japan.

The risk season runs from September to April, when stink bugs from the northern hemisphere are most likely to crawl into cargo heading to New Zealand.

Last season, biosecurity officers intercepted more than 2500 individual stink bugs at the border, mainly on vessels and cargo.

Biosecurity New Zealand is part of the Ministry for Primary Industries.