 Pesticide residues are commonly found in our food
Pesticides are chemical substances used to kill or control pests. Some occur naturally but the majority used in agriculture are synthetic chemicals. Usage increased after the second world war in an attempt to increase food production. It is estimated that over 31,000 tonnes of pesticide are now used in the UK annually.
Pesticides have many harmful effects on people and the environment. They can affect the levels of wildlife in our environment. They are toxic to species deemed as pests but can also harm or kill beneficial species which can have a knock-on effect on entire ecosystems.
Pesticides can also adversely affect human health through short term occupational poisoning or chronic long term illnesses. Some substances which may be harmless in isolation may be lethal in combination with others.
Read more about pesticides in your food...
Did you know?
311 chemicals are available to non-organic farmers to kill weeds, insects and other pests that attack crops. The most dangerous chemicals used in farming such as organophosphates have been linked with a range of problems including cancer, decreasing male fertility, foetal abnormalities, chronic fatigue syndrome in children and Parkinson's disease.
Pesticide facts
» Fact! There is official acknowledgement of the potential long term health dangers of chronic, low level exposure to combinations of pesticides – the so called 'cocktail effect'
» Fact! There are 311 licensed pesticides that are used in the UK
» Fact! Around 31,000 tonnes of pesticide are applied to UK crops every year
» Fact! The average Cox's apple is sprayed 18 times with many different chemicals
» Fact! The Co-op and Marks & Spencer have decided to move ahead and ban the use of certain pesticides where there is uncertainty about their safety.
So how do organic farmers control pests and diseases?
Organic farming systems rely on prevention rather than cure, and the primary form of pest control is through following cultural methods and best practise. Soil Association standards are based on the principle that the 'design and management of the whole farming system to achieve health, vitality and diversity of soil, crops, and environment... are the primary means to ensure that pest and disease problems are minimised'.
The incidence of pest and disease damage in organic systems is reduced using a number of fundamental practices:
- The use of sustainable crop rotations
- The maintenance of biodiversity to encourage natural predators
- The maintenance of optimum crop health
- The use of resistant plant varieties
Find out more about these practices in our information sheet Pest and disease control in organic farming. Organic growers are also encouraged to explore the use of biological control agents (predators or parasites of pests which are released into the crop) in preference to chemical inputs for insect problems. Biological control agents have been used with considerable success, particularly in glasshouses.
Organic food reduces pesticides in your diet
Organic food is the best way of reducing, if not eliminating, pesticides in your diet. Over 311 pesticides can be used on non-organic farms in the UK, many of which can be highly toxic to the environment. The Government's Pesticide Residue Committee found pesticides in over 50% of non-organic fruit and vegetables they sampled in 2006. A study by Emory University in the USA demonstrated that eating organic food is effective in reducing children's exposures to pesticides that are widely used on a variety of crops. Within one day of switching to an organic diet no traces of pesticides could be found in the children's bodies. When the children switched back to a non-organic diet, pesticides were immediately found in the children's bodies (C Lu, K Toepel, R Irish, R A Fenske, D B Barr, R Bravo (2005) 'Organic diets significantly lower children's dietary exposure to organophosphorus pesticicides', Environmental Health Perspectives, 114, 2). The Food Standards Agency says that "Eating organic food is one way to reduce consumption of pesticide residues and additives."
Can organic farmers use pesticides?
By following good organic practice the vast majority of organic farmers have no need for pesticides. In some cases, organic farmers may use a limited number of pesticides. Sometimes this can happen where organic farms are surrounded by non-organic monoculture crops and pesticide sprays which leave little space for wildlife and natural predators. This can make it more difficult for organic farmers to create fully balanced systems that keep pests and diseases within ecological limits. Other factors include a lack of resistant plant varieties for organic growers, unusual weather conditions that favour a particular pest can also mean that organic and strict cosmetic standards from some retailers mean that perfectly good organic food can be rejected for being 'blemished' or the 'wrong' size.
When this happens a limited number of pesticides can be used as a last resort. In the UK, organic farmers can use up to seven pesticides (ACOS, 2005), four of which are allowed on Soil Association farms, mainly to control insect pests and fungi (over 311 pesticides can be used in non-organic farming). They are either of natural origin (rotenone and soft soap) or simple chemical products (copper compounds and sulphur) compared to the more complex substances typically used in non-organic farming. Copper and rotenone are restricted, which means that they can only be used with consent by the certification body where the farmer provides evidence of a threat to the crop and no alternatives are available. You can find out more in Pesticides and organic farming - a last resort.
Critics of organic food often overemphasise that organic farmers sometimes use pesticides. In fact, around 10 tonnes of pesticides are used on Soil Association organic farms a year, 0.03% of the total 31,000 tonnes sprayed on UK farms. If all farmland in the UK converted to organic methods, pesticide spraying would fall by 98%. They are mainly used on two organic crops; potatoes and orchards. No pesticides are used on other organic arable crops and no herbicides (weedkillers) can be used on organic farms. All other organic arable farming in the UK has no need, and no possibility, of using pesticides.
In 2006, five Soil Association growers used rotenone and 58 used copper on 709 hectares of organic land. This represents 3% of Soil Association farmers and 2% of fully organic cropped land. The active ingredients in rotenone and soft soap are of natural original and break down rapidly when exposed to sunlight and are therefore unlikely to pose risks to the environment or occur as residues in food. Copper and sulphur occur naturally in the soil, and pests do not tend to build up resistance to them. In addition, a number of blight-resistant organic potato varieties were introduced in 2005 and it is anticipated that this will further reduce the use of copper. The Soil Association is exploring ways to phase these out in the future.
Read more - Pest and disease control in organic farming
Documents in our library about pesticides:
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