D.D.T. ALTERNATIVE “Satisfactory"’ If Procedure Right

Press, Volume CIX, Issue 32302, 21 May 1970, Page 10

D.D.T. ALTERNATIVE “Satisfactory"’ If Procedure Right

Grass grub was the stumbling block preventing a chemical other than D.D.T. being used on farms, the registrar of the Agricultural Chemicals Board (Mr F. B. Thompson) told the provincial executive of North Canterbury Federated Farmers yesterday.

Mr Thompson said that grass grub control had been the main use of D.D.T. but it was not the board’s policy to allow its use if a satisfactory alternative could be found. Fensulfothion was the most effective known alternative for controlling grass grub but its main limitation was its toxicity. Also, it was costly.

The board believed that notwithstanding the toxicity fensulfothion could be used satisfactorily by farmers provided the instructions for distribution and storage were adhered to closely. If a farmer did not have the proper facilities and storage it would be better to have a qualified contractor do the work, said Mr Thompson. Farmers were well advised not to store fensulfothion on their property.

How toxic fensulfothion was to humans was impossible to say without any record of an actual case of poisoning, said Mr Thompson As with all new chemicals, experiments were made on animals and it was difficult to compare the likely effect on humans.

However, it had been calculated that there was a 50 per cent chance of its being fatal to man if he swallowed the amount prescribed for a square yard of ground. But he could not see that if all the precautions were followed a man could be affected, said Mr Thompson.

“He would have to do something very silly indeed to be poisoned.” Fensulfothion was tested in New Zealand for five years before it was decided that it could be used satisfactorily, and its effective control of grass grub was considered to justify its registration. It was regarded as a stopgap until a satisfactory alternative was available. If an equally effective chemical with a lesser toxicity was found, fensulfothion would disappear from the market, said Mr Thompson. He emphasised that the main risk from fensulfothion was its storage and that it was important to observe the legal storage requirements.

He had heard reports of contractors becoming sick after applying fensulfothion but he would be most interested to hear of this happening if it had been applied in the prescribed manner.

Answering a question by the executive chairman (Mr

W. N. Dunlop), Mr Thompson said fensulfothion in liquid form would probably be more effective biologically, but more dangerous to handle than in granules.Asked how long it lasted once distributed, Mr Thompson said it broke down fairly readily, and there was no residue problem or any long-term contamination of the environment. A motion from the Hororata branch was carried—that the executive ask the Minister of Agriculture to have the search fbr a satisfactory and economic replacement for D.D.T. intensified immediately.