Correspondents' Correspondence
LAND, THOMAS
Correspondents' Correspondence BRIEF TAKEOUTS OF MORE THAN PERSONAL INTEREST FROM LETTERS AND OTHER COMMUNICATIONS RECEIVED BY THE EDITORS. Pesticide Breakthrough London-British research...
...The products resulting from their efforts, however, while possessing higher insecticidal activity and lower toxicity to mammals, were still unsuitable for widespread agricultural use because they retained the instability of natural pyrethrins in field conditions...
...Pesticide Breakthrough London-British research scientists have developed an inexpensive new insecticide 100 times more active than DDT that does not produce any of the long-term ill effects associated with chemical pest control...
...Thomas Land...
...The discovery of light-stable acids during recent investigations involving advanced methods of synthesis and structural analysis overcame the final scientific hurdle...
...Its effects on global food production-straggling to keep up with the rapidly increasing demands dictated by population growth-are still beyond comprehension...
...For food grains stored in Kenya and Tanzania, as well as in most other countries with hot climates, are regularly mixed with quantities of DDT-although intended for human consumption, and despite the known accumulative harmful effects of the chemical-in a desperate effort to reduce post-harvest crop losses to insects...
...Unlike DDT, dieldrin and other commonly used organo-chlorine compounds, they are harmless to mammals in normal use and leave no toxic residues to contaminate the environment, but their use is severely limited because they are unstable in air and light...
...A synthetic compound, NRDC-143 is the result of a quarter century of research into the molecular structure of pyrethrins, natural pesticides derived from an East Africa flower that act rapidly against a wide range of insect species...
...The new insecticide," explains a specialist, "retains the advantage of low mammalian toxicity and absence of toxic residues which are features of earlier pyrethroids, but does not suffer from their limitation of extreme instability in air and light...
...But the advantages of the new product may soon outweigh the loss even in that region...
...Their competitors overseas are shortly to follow suit...
...They are also far more expensive than any of the widely deployed agricultural chemicals...
...Imperial Chemical Industries and Shell Chemicals, the two largest companies of their kind in this country, are expected soon to invest in new plants for the manufacture of the pesticide, code-named NRDC-143 by the Agricultural Research Council's scientists at Harpenden...
...Indeed, a significant if accidental aspect of the NRDC-143 discovery is that it comes at a time when unprecedented famine is holding vast populations in its grip and threatening to reduce long-term environmental considerations in agriculture to a matter of secondary importance...
...The new product could also reduce the health hazard faced by agricultural workers handling potent poisons...
...One short-term victim of this development is likely to be the thriving pyrethrum industry of East Africa, which until recently enjoyed a virtual monopoly in the marketing of a natural pesticide having a high safety standard...
...Scientists at the Rothemsted Experimental Station in Harpenden began making progress in the present direction 10 years ago...
...Something like one-third of the world's grain crops are annually lost to insects while in storage...
...Used in the same manner, the new compound could both eliminate the health hazard and further reduce the annual damage done by pests...
...Extensive field tests have so far backed up the research workers' most optimistic predictions...
...a large proportion of that immense wealth may now be regularly saved...
...and the chemical industry, facing a serious world shortage of pesticides, is reliably believed to be going ahead with mass production...
...An annual international production of 20,000 tons of the new insecticide, attainable within a few years, could well satisfy global needs...
...It may, in addition, replace a range of less powerful chemicals affecting the environment that are widely used in food production and in public health projects concerned with insect-transmitted diseases, such as malaria...
Vol. 58 • March 1975 • No. 6
