These reports show that between a third and half of all fruit and vegetables sampled contain detectable traces of pesticide residues and somewhere between 3% and 4% have residues over the legal limit. Residues get into the produce when overused on crops or when crops after harvested too soon after pesticide usage but can even be detected if used according to the pesticide manufactures instructions.
A few thousand tests are a very tiny percentage of the fruit and vegetables consumed and can only provide an indication of which produce are more likely to contain residues. A high dose of chemical residues may cause a short term problem such as a stomach ache but I am more worried about the long term damage caused by small amounts of a chemical cocktail. Although the manufactures tell us that individually these chemicals are safe in minute doses, it is the damage caused by a lifetime of exposure to a cocktail of chemicals which has never been tested.
The amount of pesticides applied to crops is high and one crop may be treated with several different chemicals all leaving residues. For example, a lettuce may be treated up to five times and strawberries about twelve times.
So it is wise to grow as much of your own food as you can. Or alternatively buy organic fruit and vegetables. If using conventionally grown crops - thoroughly wash all fruit and vegetables and scrub root vegetables, discard the outer leaves of leafy crops, don't use the peel or zest for cooking and for small children peel all fruit.
If you can only afford limited organic produce or limited space to grow then concentrate on the following which have consistently been found to contain the highest pesticide residues.
Apples, strawberries, grapes, peaches, celery, peppers, spinach, nectarine, cucumbers, cherry tomatoes and potatoes.