Waikato Regional Council biosecurity staff are keeping a very close watch on the potential spread of the pest plant velvet leaf after investigations showed an initial infestation near Waihou appeared to have had some limited local spreading.
Velvet leaf is considered one of the worst crop pests in America.
In February, it was found in a maize block near Waihou after the landowner asked a seed representative what it was. It was the first time the plant had been found in the Waikato and only the fourth time ever in New Zealand.
A subsequent local survey carried out in co-operation with MAF Biosecurity New Zealand and AgResearch found velvet leaf in maize on an adjoining property.
Also, velvet leaf was found on two nearby properties that had received maize silage from the property where velvet leaf was initially found.
At this stage no other velvet leaf infestations are known in the Waikato region, although there was some on a Helensville property which has been destroyed with the site being kept under watch by Auckland Council staff.
One possibility being investigated is that the velvet leaf coming into the Waikato may have been the result of contamination of imported chicken feed or palm kernel. It was also possible that seeds had been spread in machinery used by agricultural contractors.
Waikato Regional Council biosecurity officer Wendy Mead said investigations were continuing to determine the way velvet leaf had spread to the Waikato. “It is possible velvet leaf has been in the country for a number of years but has only just started to spread and become weedy.”
In the meantime, all affected landowners in the Waihou area had responded positively to council requests to eliminate the plant and council biosecurity contractors have cleaned harvesting machinery to help prevent seeds being spread. Properties receiving maize silage from the affected areas in previous years will also be inspected.
Mrs Mead asked land ownersgenerally to be vigilantfor any signs of velvet leaf. People can report possible sightings or get advice by ringing 0800 BIOSEC