Promise of new insecticide usage

Press, 24 April 1980, Page 11

Promise of new insecticide usage

A complete shft in research emphasis promises radical changes in traditional approaches to insecticide usage. The Ministry of Agriculture scientist, Mr Gideon Du Toit, attended the Neurotox ’79 seminar at the University of York, where insect neuro-biologists and pesticide scientists from a number of countries had a fresh look at pesticides. “The aim of the seminar

was to study long-term planning of insecticidal compounds that would better serve our needs,” Mr Du Toit said.

"In the past, the standard procedure has been to take a compound and conduct extensive screening tests to find out if it affected any o’r all of a variety of insects.

“This is an expensive, time consuming, and rather ‘hit or miss’ process. “From the result of the screening the original compound may be modified to make it more specific in its action as a pesticide.” Mr Du Toit said the new approach concentrated on a detailed understanding of the biochemistry- of a specific pest, before a control was sought. “These studies concern trate particularly on insect neuro-biology and the compounds that naturally occur in the insect. “When this full understanding of the insect’s m a k e-up has been achieved, then a pesticide compound can be tailormade to fit the characteristics.

"There are great advantages; in such a system.

Not only are very expensive screening procedures eliminated, but. the end result is a pesticide made for specific uses that will not affect other life forms.”

Such studies also provided a comprehensive understanding of insect ability to adapt to pesticide attack, said Mr Du Toit. "This means that a cons trol programme may be planned using a particular compound for, say, two or three generations of the pest. “This can be followed by another tailor-made compound to hit subsequent sensitive generations and overcome resistance to the initial compound.” Workers at Rothamsted Experimental Station had been using compounds based on synthetic pyrethroids in this type of work, he said.

“Their efforts provide one of the few practical examples, so far, of the new systems at work. “The future possibilities of such methods for effective pest control, coupled with excellent environmental protection, are of great importance.**