Fears On Effects Of D.D.T. Alternatives

Press, Volume CIX, Issue 32217, 9 February 1970, Page 1

Fears On Effects Of D.D.T. Alternatives

Chemicals being proposed as alternatives to D.D.T. on control of pasture pests might be much more dangerous than the material they were replacing, said Mr J. M. Kelsey, officer-in-charge of the Lincoln sub-station of the Entomology Division of the Department of Scientific and Industrial Research, at the week-end.

Mr Kelsey is a foremost New Zealand authority on the control of grass grub and porina, the major pasture pests of Canterbury.

Mr Kelsey said there was: no scientific foundation fori the D.D.T. ban announced on: Friday by the Minister of: Agriculture (Mr Carter). Mr Carter had said that: world-wide resistance to the; use of D.D.T. reached a peak recently when laboratory tests revealed that it could cause cancer in mice—but a differing view came in a statement by a World Health Organisation expert, Mr James Wright, published in New Zealand last month. Mr Wright had said that allegations that D.D.T. could produce cancer in mice had not been substantiated. No toxic effects had been reported in the last 20 years among 200,000 spraymen employed in campaigns against malaria, nor among the 600 m to 1000 m people living in repeatedlysprayed houses. “Still Safest” No present alternative method of pasture pest control was as reliable, safe or as cheap as D.D.T., Mr Kelsey said.

The Agricultural Chemicals Board should say openly that it did not think that D.D.T.

was dangerous but that it was being influenced by pressure for reduced residue tolerances in importing countries, he said. It was unfortunate that farmers would have to use much more expensive materials. And one of the socalled short life alternatives that Mr Carter had talked about was fensulfothion, which Mr Kelsey had found to be still killing soil organisms after a year. It was one of the materials in the organophosphate group and Mr Kelsey warned at the annual conference of. the Weed and Pest Control Society last year that these should not be released for general use in agriculture until subjected to much closer study for possible side effects. His investigations, he said, had involved only one application of the chemicals and the effects of many of the insecticides in the organophosphate group were likely to be serious if annual applications to pasture or crop became necessary, as they almost certainly would be for grass 'grub and porina.

Fensulfothion' was highly toxic to human beings at the level of only twb to four parts per million of body-weight. Contractors handling it could be endangered. Last year on 12 farms in Canterbury, Mr Kelsey said, the application of fensulfothian and parathion had killed 360 seagulls, magpies and starlings. And where 401 b of 5 per cent fensulfothian granules had been applied on 25facres at Fairlie on December 30 for grass grub control, 20 magpies and a Paradise duck had died by January 15. View Contested At the conference last year Mr Kelsey said that a factor in the world-wide trend to replace long-residue chemicals was that commercial organisations preferred to sell short-life materials requiring annual use rather than the long-lasting chemicals. This view was strongly contested by other speakers. Commenting on Friday about Federated Farmers’ acceptance of the Minister’s request for a D.D.T. ban, Mr A. F. Wright, chairman of the pasture pests committee of the three provinces of Federated Farmers in Canterbury, said that because of the continued reduction in residue tolerances in importing countries, farmers their long-term export future at stake—really had no alternative but to agree to the Government’s proposals.

The fact that alternative pesticides were on the market meant that the Government must think they were satisfactory and safe.