Aggressive pest plant discovered in Hawke's Bay

Hawke’s Bay Regional Council has identified Senegal tea in Te Awa Mokotūāraro (Clive River) and the Karamū Stream – marking the first time the pest has been found in the region.

Listed as an Exclusion Pest under the Hawke’s Bay Regional Pest Management Plan 2018-2023, Senegal tea is an aquatic and aggressive pest native to South America.

Regional Council Catchment Management Lead Biosecurity Matt Short says the next few weeks will be crucial to determine the spread.

“Senegal tea becomes dormant over winter and dies back to its roots, then re-sprouts in spring. With the plant already dying back in places, it’s important we use this small window to identify the scale of the spread.”

“The plant was initially detected using Environmental DNA (eDNA) in water samples taken from Te Awa Mokotūāraro. A powerful tool for biosecurity, eDNA identifies DNA excreted or shed from organisms into the environment – helping to detect invasive species earlier.”

“We will now be surveying all streams and inlets that lead to the two waterways to find the locations and encouraging the community to play their part in protecting our awa.”

“We’re asking everyone using these waterways - whether you’re on a boat, a jet ski or walking on the berms – please check your gear and equipment for any weed fragments and leave them at the site, clean your gear thoroughly, then leave it out to dry before using again.”

“Following the check, clean, dry method provides us with the best chance to help stop the spread.”

Senegal tea forms rounded bushes up to 1.5m tall. Usually rooted on the edge of waterways, the pest plant spreads quickly and forms infestations over deep water, blocking drains and causing flooding. Senegal tea also outcompetes all other species in shallow freshwater habitats and prevents native species establishing, while blocking light and food sources for other species.

Once surveying has been completed and the full extent of the infestation is known, Regional Council will finalise a control and management plan with a goal of slowing the spread and eradicating the weed.

To learn more about Senegal tea, visit Senegal tea - Pest Hub | Hawke's Bay Regional Council (hbrc.govt.nz).

12 June 2024

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