Insecticide

An insecticide is a pesticide made to kill insects and spiders.

Insects are very tough animals that have adapted to live and various climates and places.  Therefore, the poison used to kill them is also poisonous to humans.  It can be dangerous when you have vegetables.  This is why often people will rub an apple on cloth before eating it.  This polishes the natural wax on apple and rubs away some of the pesticides.  If you do not clean the clothing there is a risk pesticide might build up.