Thanks to an observant kiwifruit grower, a recent detection of Bamboo Borer (Chlorophorus annularis) in imported stakes from China did not go undetected.

After noticing an unusual pest in his bamboo stakes during the planting of new vines the grower immediately reported the find to the Biosecurity New Zealand hotline on 0800 80 99 66, and sent a sample to the Plant Health and Environment Laboratory (PHEL) for ID.

The sample was quickly confirmed as Bamboo Borer - a regulated, unwanted pest originally inhabiting subtropical and tropical regions of South-East Asia but which has now been introduced to many more countries through the movement of bamboo (although it can infest a range of species).

While it is a tropical species and New Zealand winter temperatures are likely a limiting factor in the borer’s ability to establish at this time of year, Biosecurity New Zealand began a formal investigation to ensure any residual risk was mitigated. This included tracing, which sourced the bamboo stakes back to rural supply chain merchant PGG Wrightson (PGW). Once notified, PGW rapidly undertook further tracing of all those who had received stakes from the same consignment, many of which were kiwifruit growers, and initiated a product recall – highlighting the real value in keeping records of the movements of goods and having them readily accessible.

Notably, KVH, Biosecurity New Zealand, and PGW all worked together to assist an affected and concerned grower with a large quantity of bamboo stored across several orchards. We inspected the bamboo for insects and if frass was seen we delved deeper by cutting open the bamboo stakes. Two sites were clean but live borer were found at one, so a management plan was put in place which included burning the bamboo on site, mitigating any further risk.

The bamboo stakes had been treated offshore with Methyl Bromide (as per import requirements) and then inspected at our border; however, it appears the stakes were too tightly packed which didn’t allow for the treatment to penetrate all parts of the container they were in, resulting in “cold spots” or areas that didn’t get fumigated. This aligns with the low infestation rate that was found during the investigation.

KVH is in further discussion with Biosecurity New Zealand regarding requirements around stacking containers and ensuring this is done appropriately to allow treatment penetration. PGW is having similar discussions with their suppliers.

Thanks to the vigilant grower who did everything right – he saw something unusual and swiftly reported it, which likely made all the difference to a successful investigation where risk was well managed. The case is also a good example of how easily different groups within the kiwifruit industry can share information and work together to mitigate risk to our industry and ensure less impact.