Residue Problems In Australia

Press, Volume CII, Issue 30286, 12 November 1963, Page 23

Residue Problems In Australia

In Australia the problem posed by residues in primary produce was in many ways more serious than in New Zealand, Mr I. W. Montgomery, manager of technical service and development in the field of veterinary and agricultural chemicals for Imperial Chemical Industries of Australia and New Zealand, Ltd., said in Christchurch at the week-end. Mr Montgomery said that D.D.T. was the only chemical that would control both the cattle tick and buffalo fly at reasonable cost, but tire use of D.D.T. and other chlorinated hydrocarbons for this Curpose had now been anned.

Other chemicals controlled either one or other of these pests. In the face of this situation, he said, it had been necessary to use chemicals that were much more acutely toxic to cattle and to the men handling the materials. Nevertheless. Mr Montgomery said, there was no denying the essential soundness of the measures taken to protect the valuable meat export trade with the United States. In the United States there was talk of good agricultural practice, but what was good agricultural practice there might not be so in Australia and New Zealand, where requirements for pest control might well be different. In the United States there were neither cattle ticks nor buffalo flies.

At present, Mr Montgomery said, regulations governing the use of agricultural chemicals like D.D.T. varied from state to state in Australia, but an organo-phosphate material called imidan was working extremely well against two of the main pasture pests. First Use Mr Montgomery was the first man to use phenothiazine for control of internal parasites of livestock in 1938. For many years since then it has been one of the main materials used for this purpose in Australia and New Zealand.

For 10 years Mr Montgomery was a parasitoligist with the Commonwealth Scientific and Industrial Research Organisation, and when he first used phenothiazine in the field he was with the organisation's laboratory at Armidale in northern New South Wales. He said that at the time he was learning German and it was as a result of reading German literature that the chemical was used. "We were greatly excited about it because it was good stuff,” said Mr Montgomery. The original material used in Australia came from the England from the company with which Mr Montgomery is now employed in Australia. He said it was white in colour and was probably very pure but the chemical subsequently manufactured in Australia was not so pure. In 1949 Mr Montgomery visited New Zealand when the performance of phenothiazine was in question. There had been an allegation that the parasites had developed a resistance to it. This was hard tn believe, he said, and when he returned to

Australia his old laboratory, the McMaster Laboratory, had been persuaded to do some investigations on particle size which emphasised the importance of this, and in the company's own j laboratory work had also [stressed the significance of I purity. Still Has Place | Mr Montgomery said that iit would not be true to say , that phenothiazine had been largely superseded by newer chemicals. It still had a high level of efficiency for dealing with certain parasites in sheep and was much less costly than many L f the modern chemicals. It still had a place in a combination with some other chemical to give a broader spectrum of effectiveness. Mixtures of one, two or more chemicals could give greater efficiency but still at reasonable cost. The research work of his company was directed at both the cost aspect as well as the efficiency of the product, he said.

While phenothiazine had held its place for 20 years, Mr Montgomery said, in the last few years a series of new chemicals had been developed of which the three most important groups were the benzimadozoles, the pyridines and the organo-phos-phates. For sheep the main development had been in the benzimadozoles or the benzimadozoles with phenothiazine. In the first instance there was high efficiency but at relatively high cost. In the second there was equivalent efficiency but at a lower cost. His company was interested in the second proposition and it was about its development that he had come to New Zealand to talk. Its new preparation embraced efficiency against immature parasites which Mr Montgomery said was important in relation to reinfestation, development of secondary infestations and pasture contamination. Tests at Ruakura and Wallaceville animal research stations with the material had shown that it was giving a similar level of efficiency to that recorded in Australia. Mr Montgomery said that it still had the characteristic of staining wool but in Australia, with its high proportion of Merino sheep and widespread usage of phenothiazine, wool brokers and buyers no longer regarded staining from phenothiazine as a real problem because of care exercised in its use.