Infestations of highly invasive pest plant velvetleaf have been discovered on five more farms in the Waikato recently.

Waikato Regional Council is already working to contain and eradicate velvetleaf on farms located in Matamata, Piopio, Atiamuri and Ngakuru as part of its response to infected fodder beet crops.

Infestations of velvetleaf have been discovered on five more Waikato farms recently. Photo: File

The additional five infestations appear to be related to the movement of infested maize or maize silage throughout the region, particular in the Matamata-Piako, North Waikato and South Waikato districts.

WRC biosecurity spokesman Patrick Whaley they're also inspecting a further 14 sites where it is suspected velvetleaf might be growing.

'These latest developments mark a significant escalation in the scale of the velvetleaf problem in our region,” explains Patrick.

'We will be working hard to help landowners manage the situation, in co-operation with the Ministry for Primary Industries which is leading the national response to velvetleaf infestations linked to potentially contaminated fodder beet seed.”

In response to the magnitude of the discoveries and the potential for more sites to be uncovered, council's set up an incident management team which is developing a long term plan to build on work already underway.

Patrick says it's unclear at this stage how the new infestations occurred and the source of the outbreaks would form part of ongoing investigations.

'For now we strongly encourage landowners to keep an eye out for this pest and ensure they don't do anything to help spread it,” he says.

Chairperson Paula Southgate says the welfare needs of affected landowners was of the highest priority for the regional council.

Farm management of velvetleaf is complex and can have a significant impact on individual landowners, she says.

'Staff are really conscious of ensuring farmers have the support they need and so the council is working closely with the Rural Support Trust and Waikato Civil Defence Emergency Management welfare staff.”

WHAT IS VELVETLEAF?

Highly invasive pest plant velvetleaf flowering. Photo: File

Velvetleaf is one of the world's most invasive pest plants, damaging crops by competing with them for nutrients and water. In New Zealand, it is an unwanted organism under the Biosecurity Act.

It is an annual broad-leaved herb that grows between one and 2.5 metres tall. It has buttery-yellow flowers about three centimetres across. It flowers from spring through autumn. Leaves are large, heart-shaped and are velvety to the touch.

Seedlings are vigorous and the plant grows rapidly in the first few months after germination. Seeds remain viable for up to 60 years. The seeds are spread by water, farm machinery when harvesting grain, through livestock and as a contaminant of grain.

Farmers are being advised to photograph any plants and mark their location so they can be found again easily. Do not pull up plants or graze stock in infested crops.

A ministry or regional council staff member will provide strict protocols to follow which includes carefully removing plants to make sure seed is not spread.

To report any signs of velvetleaf call the Ministry for Primary Industries on 0800-80-99-66.