29 JUNE 1956, Page 27

THE RESEARCHERS' WORRIES

Modern insecticides may soon have solved all the problems that farmers and gardeners would like them to, for they become more selective and positive all the time. A great deal has been done since one sort of chlorinated hydrocarbon resulted in a DDT-resistant fly, and among the armoury of the bug-killer are several hydrocarbons and organic phosphates which constitute a formidable collection of in- secticides. The insect is now attacked with these two main groups and, as with the latest weed- killers, the countryman can only applaud the immediate result and ponder the ultimate effect of the use of these methods. Biologists and chemists tend to be maligned for doing what they have been asked to do. 'Kill my leather- jackets, greenflies, sawflies, this bug and that.' demands the grower. If the only thing the spray killed happened to be the pest it is designed to kill no one would complain, but the man who invents the spray must keep his wits about him, particularly in places like North America, where great areas of timber and wild country are being sprayed from the

air. Wild life may be seriously affected.