Avoiding the adverse effects of pesticides.

Abstract

'It may be advantageous to encourage minimal populations of pests and weeds to persist in and around crops, especially in winter, to sustain populations of beneficial insects at a level high enough to retard rapid multiplication of pests in spring.' (Graham-Bryce et al., 1980).

There has been a steady increase over the past fifty years in the number of pesticides necessary to protect cereal crops. Taking, for example, the Sussex study area cereal crops as a whole, approximately five different treatments are now used between sowing and harvesting, involving twenty-five different chemicals plus a couple of seed dressings and herbicides to clear stubbles. Elsewhere in Britain MAFF survey data show that the situation in cereal crops is similar (e.g. Stanley and Hardy 1984).

It is therefore appropriate that the first questions one should ask should relate to the reasons for the increase. Will it continue? Is the increase evidence of a gigantic pesticides treadmill? Will even more pesticides be used in future? The answers could profoundly influence the overall approach to the problem of adverse effects of pesticides.