Pesticides are a series of chemicals that are used to prevent or destroy pests They include insecticide  herbicides  fungicides Although for the purpose of this post  we will be focusing on pesticides used in agriculture  it is important to mention that pesticides are often used at home (cockroach  rat  flea  tick sprays or poisons  pet collars  products that kill mold or mildew) and even on our children (insect repellents) and on the areas where they most often play (some lawn and gardening products such as weed killers)