Mites released to tame old man’s beard
Marlborough District Council biosecurity staff have introduced the leaf-galling mite (Clematis vitalba) in two locations as part of a New Zealand-first bid to control the highly invasive pest plant, old man's beard.
Early this month a small number of plants were infected' with the gall mite before being planted at sites just out of Havelock and in Northbank
Senior Biosecurity Officer Brent Holms says old man's beard is a serious problem throughout the Marlborough region.
Old man's beard is one of New Zealand's worst and most widespread invasive alien plant. It's a deciduous, climbing, layering vine that can grow up to 20 metres high and in suitable habitats it rapidly dominates, smothers and eventually kills all types of vegetation, Mr Holms said.
This project could help dramatically slow the spread and reduce the impact of this highly invasive and difficult to control species - an exciting prospect, he said.
The Aceria vitalbae mite is only 1mm long and disperses passively with the help of the wind to find new old man's beard plants. The gall mite works by forming galls in the host plant, forcing the host to redirect resources to the galls, which in turn reduces the host's growth rate and can cause shoots to die back.
The mite was approved for release in New Zealand by the Environmental Protection Authority in 2018 after a very thorough process. They have been reared by Manaaki Whenua - Landcare Research to numbers that can now be released into wild old man's beard infestations.
Mr Holms said old man's beard requires intensive, manual effort to control and requires follow-up maintenance control. The use of a biological control like the gall mite is a game changer and allows nature to regain some sort of equilibrium.
While it is early days, and we need to wait for the mites to mature to see the real results, we are hopeful that it will perform in a similar way to the closely related broom gall mite that was introduced in 2008 and is now having a significant impact on broom.
It would be great to see similar results with the old man's beard mite in coming years. If successful the mites will form part of the arsenal in the fight against old man's beard in Marlborough, he said.
Seven other Councils are involved in the programme to release the Aceria vitalbae mite in regions including Bay of Plenty, Manawatū-Whanganui, Taranaki, Wellington, Tasman, Canterbury, and Otago. Research and testing of biological agents like the old man's beard mite is collectively funded by regional councils/unitary authorities throughout New Zealand.
Disclaimer
The information in this media statement was correct at time of publication. Changes in circumstances after the time of publication may impact on the accuracy of the information.