There's no escaping pesticides

Simon Jones's tirade ("Scientists gang up on organic food", 11 December) made us think he was writing under a nom de plume for the Soil Association; a group which asserts that better crops are produced by minerals from manure breakdown, and that organic pesticides are somehow better than synthetic pesticides. Neither assertion stands any brief critical examination. That is why scientists like ourselves prefer farming to be based on the best available knowledge.

The fairy tale about Sir John Krebs and the single carrot is a fabrication made up by the Soil Association, angered that he described their expensive products as no better in health and safety terms than conventional products costing half the price.

There are many thousands of measurements of synthetic pesticide residues in conventional and organic food, and Sir John's objective summary was accurate. To correct one of the major misconceptions propagated by Jones and others of this persuasion, organic food is not pesticide free; it contains, on average, about half the synthetic pesticide residues as conventional food. However, these residues are irrelevant for safety concerns, given that all fruits and vegetables, both organic and conventional, contain a very much higher content of natural pesticides, all of which are carcinogenic in rodent tests. We had always thought that conspiracy theories were the products of right-wing propaganda in the manner of "reds under the bed". In a rather novel reversal of this slander, Jones sees scientists and commerce under the bed in an unholy alliance to keep food prices low!

Anthony Trewavas (Edinburgh)
Willie Russell (St Andrews)
Members of Scientists for Labour
Harrow, Middlesex

Simon Jones is anxious to protect the reputation of organic foods and, to do so, he accuses many scientists of conflicts of interest; but he is himself selective of facts. He quotes Jules Pretty: "There are 95,000 cases of food poisoning a year in Britain and almost all are from conventional food." That is hardly surprising since almost all food eaten in the UK is conventional, while organic accounts for a very small minority. Thus, his claim that this proves organic food is safe is ridiculous.

Is he not aware that organic farmers are encouraged to use human and animal sewage on their crops, and that they are allowed by the Soil Association to spray their crops with copper-based fungicides, with sulphur, with Bacillus thuringiensis (the very same stuff that environmentalists decry being used in insect-resistant crops) and some plant-derived compounds, such as rotenone, for which chronic toxicity studies have not been carried out although they are known to be extremely toxic to fish?

Alan Williams