Relative Toxicity Organisms can't differentiate between "natural"and “synthetic”chemicals “Synthetic"”does not mean toxic or poisonous "Natural"does not mean safe or even low risk Chemicals must be evaluated in their biological context of behavior in organisms 。 Mode of action,not source,is the concern Pesticides should be treated with care and proper respect but so should household cleaners,gasoline and kerosene,bleaches, paints and all other chemicals Mistretta USFS R-8 Relative Toxicity • Organisms can’t differentiate between “natural” and “synthetic” chemicals • “Synthetic” does not mean toxic or poisonous • “Natural” does not mean safe or even low risk • Chemicals must be evaluated in their biological context of behavior in organisms • Mode of action, not source, is the concern • Pesticides should be treated with care and proper respect – but so should household cleaners, gasoline and kerosene, bleaches, paints and all other chemicals Mistretta USFS R-8