Otago Regional Council director of environmental monitoring and operations Scott MacLean said the affected Otago properties are spread through North, South and Central Otago.
ORC staff phoned 55 property owners at the weekend, whose properties were identified as having planted either Bangor or Kyros varieties of fodder beet, varieties confirmed as having been affected with velvetleaf seed.
‘‘From those interviewed we now have a further 600 hectares of fodder beet crops to inspect as quickly as possible.''
The council was aware cattle farms that had grown possibly affected beet crops were keen to start feeding their stock, but were also aware velvetleaf plants were reaching maturity and likely to be dropping seed.
‘‘Therefore, there is great urgency to work with the farming community to minimise the impact of velvetleaf now and in the long term.''
Environment Southland biosecurity manager Richard Bowman said in the past week, seven plants had been found on four Southland properties. ES teams had been out every day, but with an estimated 1200ha to search, help was needed, he said.
Yesterday, 27 staff from AsureQuality, which contracts to the Ministry for Primary Industries (MPI), arrived in Invercargill. They would stay until Sunday, he said. As many as 50 people would be out in the field.
Velvetleaf is a serious problem overseas, damaging crops by competing with them for nutrients and water. It is an Unwanted Organism under New Zealand's Biosecurity Act.
In Southland, the plants were probably two or three weeks away from seeding, he said.
Properties on a list of farmers known to have bought potentially contaminated seed would be inspected first, Mr Bowman said. But he urged all farmers to walk their fields.
People finding suspect plants should photograph them, mark the location, and phone MPI on 0800-809-966. An MPI representative or ES staff member would remove the plant to make sure seed was not spread.
