Pest plant rears its head again in Waikato
The discovery of velvet leaf on two new properties in the Waikato region has sparked a renewed call from the Waikato Regional Council for robust on-farm biosecurity measures.
The council’s biosecurity pest plants team leader Darion Embling said the first new detections of the highly invasive pest plant in the region since 2019 were 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 velvet leaf in this region since it was first discovered in 2011, so it is extremely disappointing to have these two new outbreaks,” Embling said.
“We can’t be certain how velvet leaf 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.”
He said the council’s focus was now on tracing machinery and crop movement, which was critical to ensuring the risk of its spread was effectively managed.
As a declared pest in the Waikato region, velvet leaf 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,” Embling said.
“We are also liaising with the cropping industry, in particular, with a reminder around the ongoing risk of velvet leaf in the Waikato region and the importance of good hygiene practices.”
Velvet leaf 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.
It is 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.
“The discovery of velvet leaf on a property can significantly impact farming businesses, as paddocks are unable to be cropped for some time,” Embling said.
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.
The plant is an annual broad-leaved herb that grows between one and 2.5 metres tall.
It has buttery-yellow flowers about three centimetres across and flowers from spring through to autumn.