Pest controllers in Hawkes Bay have rejected a suggestion by Green Party co-leader Jeanette Fitzsimons that the ashes of dead possums could control the menace.
The control method known as "possum peppering" was first proposed in the 1920s by philosopher Rudolf Steiner.
It involves burning possum testicles and other organs into ashes, diluting them in a homoeopathic manner and spraying forests with the solution. Supporters of the idea believe that will make possums infertile, and some organic farmers in the Bay of Plenty have used the method.
Ms Fitzsimons suggested its use in response to a recent request by the Animal Health Board and the Department of Conservation for the use of 1080 poison to be reassessed.
Hawkes Bay Regional Council biosecurity manager Andrew Wilke said yesterday that he would like to see tests that proved possum peppering worked, but he doubted it would.
New Zealand Skeptics spokesman Denis Dutton said Ms Fitzsimons was plummeting to new depths of "green idiocy".
"If ashes ward off animals of the same species, no one would be able to go near the mantelpiece in the lounge where grandma's ashes rest."
If possum peppering was the best idea the Green Party could come up with, it ought to do something it was better suited to, such as tarot or horoscopes.
New Zealand is the only country in the world where possum peppering has been tested scientifically. It was done by the Forest Research Institute in the early 1990s, but the results were inconclusive.
The editor of the now-defunct NZ Science Monthly, Vicki Hyde, challenged the institute's tests.
"Steiner's concepts certainly fall into the paranormal camp and, from my observations, have very little connection with the way the world actually works," she said.
"Here in New Zealand we tend to associate him with the relatively benign approach to alternative education through the schools that bear his name, but I don't think that that presents a valid reason to waste a significant amount of public time and money on his more questionable ideas."
The executive secretary of the Bio Dynamic Farming and Gardening Association, David Wright, has claimed peppering has worked for some farmers, although he could not pinpoint why.
Landcare scientist Dave Ramsey said the tests by the forest institute were sufficient to prove the method did not work.
Act environment spokesman Gerry Eckhoff suggested all farmers would be using the method if there was any suggestion it worked.
"Perhaps we should consider burying cow horns stuffed with animal manure and burned thistles to ensure the demise of unwanted pasture weeds."