Green Party leader Jeanette Fitzsimons wants the Government to try controlling possums with the ashes of dead possums instead of using genetic modification or 1080 poison.
The technique, known as "peppering", was proposed by the philosopher Rudolf Steiner in the 1920s and is used by some organic kiwifruit farmers in the
Bay of Plenty.
Ms Fitzsimons told a conference of Engineers for Social Responsibility in Wellington on Saturday that the country had to look for other ways of controlling possums.
"Aerial spraying of 1080 clearly raises worrying questions about the effect on water, nutrients in the soil and non-target species," she said.
"I don't think the genetically modified carrot bait is likely to work [either].
"I can't see how a bait which stops possums breeding, but allows them to chomp through several years of foliage and allows all those which haven't eaten the bait to breed to fill up the gaps, will ever be a solution."
The Animal Health Board asked the Environmental Risk Management Authority last week to review the use of 1080 poison, which is spread on about two million hectares of land every year.
New Zealand uses about 80 per cent of the world's 1080 production.
The co-founder of the bio-dynamic Garuda Institute in Te Puke, Peter Bacchus, said he prepared sprays of the ashes of the sensory organs such as skin and hair of possums, birds and other animals to help organic farmers protect their crops.
He believed burning "inverted" the organs' fertility, causing animals of the same species in the locality to become infertile.
Mr Bacchus carried out a large-scale trial using aerial spraying of possum ash for a Buddhist trust just north of Thames in 1999.
But Mr Bacchus said monitoring stopped after only three months, and needed to take place over a five-year breeding cycle.
The science manager for biosecurity and pest management for Landcare Research, Dr Phil Cowan, said the crown research institute would be happy to carry out a study if funding could be found.
nzherald.co.nz/environment
