New velvetleaf discoveries a wake up call for ag sector

The discovery of velvetleaf on two new properties in the Waikato region has sparked a renewed call from Waikato Regional Council for robust biosecurity measures on farm.

The first new detections of the highly invasive pest plant in the region since 2019 have been found in a commercial maize block, as well as in a maize paddock.

“There is a significant amount of work that has gone into controlling velvetleaf in this region since it was first discovered in 2011, so it is extremely disappointing to have these two new outbreaks,” said Waikato Regional Council’s biosecurity pest plants team leader Darion Embling.

“We can’t be certain how velvetleaf has spread to these two properties. However, tracing has historically identified machinery and infested maize silage as the most common vectors, which demonstrates the need for continued vigilance by farmers and growers, as well as rigorous machinery hygiene protocols by the cropping sector.

“Our focus is on tracing machinery and crop movement, which is critical to ensuring the risk of spread beyond these properties is effectively managed,” Mr Embling said.

As a declared pest in the Waikato there are strict rules. Velvetleaf can't be spread, landowners are responsible for destroying the pest, and all machinery leaving an infested property must be cleaned.

“We’re working closely with the owners/managers on the affected properties to develop biosecurity farm management plans. We are also liaising with the cropping industry, in particular, with a reminder around the ongoing risk of velvetleaf in the Waikato region and the importance of good hygiene practices.

“The discovery of velvetleaf on a property can significantly impact farming businesses, as paddocks are unable to be cropped for some time. So we are doing what we can to support these landowners,” Mr Embling said.

Velvetleaf was first discovered in the region in 2011, but the scale of finds escalated in 2016 with the arrival of infested fodder beet seeds imported from overseas.

The majority of the infested properties are in the north Waikato, Matamata-Piako and south Waikato districts. Pest plant officers have been working with landowners/managers to develop biosecurity farm management plans to manage the risk of spread on 60 properties.

Velvetleaf is one of the world’s most invasive pest plants, damaging crops by competing with them for nutrients, space 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. A mature plant can have as many 15,000 viable seeds.

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.

See waikatoregion.govt.nz/velvetleaf for more information on this pest.