Abstract
Much of the success of modern agriculture is due to pesticide technology. Because weeds pose the greatest threat to crop yields, the largest class of pesticides used today is herbicides. Herbicides include products whose active ingredients represent a wide range of chemical families; yet most constitute a minimal potential hazard to man and the environment. Criteria typically used to determine potential hazard are mammalian and piscine toxicity, persistence, and bioaccumulation. By evaluating these criteria and assigning numerical values it is possible to devise a ranking of pesticides such as that developed by Weber (51). This list identifies those pesticides most likely to have some undesirable activity, either before or after they are applied. All herbicides ranked well below organochlorine insecticides in hazard rating and most were less hazardous than the organophosphate and carbamate insecticides. However, any substance, when used improperly, has the potential to cause problems, and for this reason all chemicals should be handled with caution.