Letter: Going organic

Sir: It is not true to say that organic crops are completely free from pesticides ("Foods for thought", 21 September). The organic farmer has access to an array of "natural" products, including the notorious Bt insecticide. Some natural compounds are highly toxic.

Most organic crops are grown using conventionally grown seed. Plans to allow only organically grown seed have been put back, and, indeed, one significant organic grower admits that he would not be able to continue growing many crops organically if he were obliged to use organically grown seed. The disease burden carried by the seed would be too great to risk.

Inorganic fertilisers, used on vegetables and fruit which are consumed raw, offer significantly lower acute health risks than organic animal manure. Organic fertilisers by their very nature carry a higher risk of food poisoning from E-coli.

An organic production system is much less productive than the equivalent conventional farm - by as much as 50 per cent in some situations. Current levels of consumption could not be supported by organic agriculture without a dramatic increase in cropped land, thereby putting even greater pressure on unfarmed land around the world.

It is not surprising that around 1 per cent of foods show traces in excess of maximum residue levels. MRLs are not a safety level. The safe levels are often many hundred or thousand times greater than the MRL.

The advent of GM technology ought to bring huge benefits in reducing the environmental impact of food production. In setting its face so rigidly against genetic modification in Britain, the organic movement may well have done more environmental harm than good.

W R N TAPP

Birchington, Kent