ADVANTAGES OUTWEIGH DISADVANTAGES

Press, Volume CIX, Issue 32221, 13 February 1970, Page 8

ADVANTAGES OUTWEIGH DISADVANTAGES

“Notwithstanding the limitations of the organophosphorus insecticides registered by the Agricultural Chemicals Board and recommended by the New Zealand Department of Agriculture for the control of grass grub, it is considered that the advantages of controlling grass grub by these recommended materials outweigh the disadvantages and they should be made available to farmers,” Mr F. B. Thompson, superintendent of agricultural chemicals and registrar of the Agricultural Chemicals Board, said this week in a statement to “The Press.”

Mr Thompson was replying to the comments of Mr J. M. Kelsey, officer-in-charge of the Lincoln sub-

station of the Entomology Division of the Department of Scientific and Industrial Research that chemicals being proposed as alternatives to D.D.T. for control of pasture pests might be much more dangerous to people handling them than the material they were replacing and also that such chemicals in the organophosphate group could have a harmful effect on soil organisms. “The Agricultural Chemicals Board registers pesticides if. in its opinion, the products may be used effectively and safely when used in accordance with the label directions.” Mr Thompson said in discussing the toxicity of organophosphorus insecticides to man. “Many commodities are hazardous if not used properly. Motor-cars for instance, if not handled carefully kill people every week. "The board considers that the organophosphorus insecticides recommended for the control of grass grub may be used safely if label directions are followed. “Statistics show that most cases of poisonings, not only with pesticides but also with household commodities, result from small children obtaining access to the materials. It is illegal to store

the more toxic agricultural chemicals in places accessible to children and unauthorised persons. “There is no doubt that in many instances users of agricultural chemicals do not observe their legal obligations in this respect, and the board has published articles on this subject which have recently appeared in several publications. The board is actively seeking the co-op-eration of the press in publicising the necessity to store these materials under proper conditions.” On the subject of the toxicity of organophosphorus insecticides to other soil organisms, Mr Thompson says: “The board registered these chemicals for use against grass grub on the advice of senior officers of the entomology division of the D.5.1.R., and the research division of the Department of Agriculture. “This action was taken in the full knowledge that certain organophosphorus insecticides may kill some organisms in the soil other than grass grubs. In registering these materials the board asked the scientists to investigate this aspect more fully. “There is no doubt that if subsequent investigations reveal that the adverse side effects of the organophosphorus insecticides used in agriculture impair the productivity of the soil, the registration of these materials would be reconsidered. “There is no perfect insecticide. If D.D.T. was being introduced how for the first time it is very doubtful indeed, in the light of current knowledge of the side effects of it, whether it would be approved for widespread applications.

"However, notwithstanding its limitations, D.D.T. has proved a very valuable tool for the control of grass grub over the last 20 years “Agricultural chemical manufacturers throughout the world are keenly aware of the need to find an alternative to D.D.T.,” said Mr Thompson.