Beetle could threaten NZ avocados

The granulate ambrosia beetle.

An unwanted pest first found in New Zealand in four Auckland areas on February 20 could pose a serious threat to our country’s avocado industry.

And that’s why Biosecurity New Zealand is asking the public to report any sign of the wood-boring granulate ambrosia beetle.

According to Biosecurity NZ, while it’s unclear how the beetle arrived in NZ, the evidence to date suggests it may have been in the country for at least two years.

“The beetle is regarded as a serious pest overseas. It is known to feed on a wide range of broadleaf trees, including horticultural species such as avocado, and can spread fungal diseases,” says Biosecurity NZ biosecurity surveillance and incursion manager Brendan Gould.

Biosecurity NZ is currently assessing the potential risk from the beetle to NZ, says Brendan.

“We need to know if NZ has a wider population, which is why we are asking the public to report any possible sightings.”

The beetle resides under bark, making it difficult to detect. Brendan says a tell-tale sign is distinctive protrusions of frass – compacted sawdust – from bark that look like toothpicks. They are caused by the beetles pushing frass out of tunnels bored into the trees. Other symptoms include sap oozing from the tunnel entrances and branch dieback.

Brendan says officials are working with local authorities to identify the extent of the spread, including inspecting known host trees and placing lured traps around the detection sites.

Biosecurity NZ has also directed the removal of infested oak trees at one of the sites. The beetle is native to tropical and subtropical East Asia. It’s been found in many areas in the world, including Africa, the USA, Central America, Europe, some Pacific Islands, and most recently in Queensland in Australia.

Anyone who believes they’ve seen the granulate ambrosia beetle – or any sign of frass on trees – should take a photo and call Biosecurity NZ’s exotic pests and diseases hotline on 0800 80 99 66.


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