Exposure to pesticides sprayed on fruits, vegetables and other plants could increase the risk of devastating motor neurone disease by up to 70 per cent, a study has found. Those who work with the chemicals, such as farmers, are dramatically more likely to develop amyotrophic lateral sclerosis (ALS) - the most common form of motor neurone disease. ALS, which affects around 5,000 Britons, causes nerve cells that control movement to deteriorate.This leads to a host of life-ruining symptoms like muscle weakness, loss of mobility, speech difficulties and changes to thinking and behaviour – robbing victims of their independence.Just 20 per cent of ALS patients live for longer than five years. And in many cases, the prognosis is as little as two years.The cause of the disorder is not yet fully known, but scientists - from the Robert Suave Institute For Research in Quebec, have identified an interesting theory. The team reviewed almost 800 studies but used 11 for their analysis, and involved data from more than 2,000 people with ALS or another type of MND.They found that those who had been exposed to pesticides at work were around 60 per cent more likely to develop ALS than those who had never been exposed. Farmers and workers exposed to pesticides could be at a 70 per cent higher risk of developing deadly motor neurone diseaseBut those exposed mostly to herbicides - or weedkiller -had a 70 per cent increased risk.Pesticides are chemicals used to protect crops by killing or controlling weeds, insects and fungi.The main types are herbicides, well as insecticides and fungicides.Even lower levels of exposure to pesticides of any kind were associated with around double the risk. Interestingly, when researchers analysed men and women separately, they discovered the worrying link only applied to men. Commenting on the findings in the journal Occupational and Environmental Medicine, the experts urged officials to introduce 'interventions aimed at reducing exposure during occupational pesticide use.'The World Health Organisation has branded pesticides 'intrinsically toxic' and deemed them 'among the leading causes of death by self-poisoning'.Several pesticides are not permitted for use in the UK.