Nothing could be further from the truth. Plant-derived poisons are only sometimes less toxic to man than synthetic pesticides. Rotenone, from the roots of derris plants, is toxic if swallowed or inhaled. Both pyrethrum and rotenone are low in toxicity to mammals yet highly toxic to fish. The yardstick for comparing acute, short-term toxicity is the LD50 or lethal dosage needed to kill fifty percent of a group of test animals (rats, rabbits, etc.). When you compare LD50 figures, the chemical insecticides Malathion and Sevin rank safer than nicotine sulfate, a botanical poison derived from tobacco.
No matter whether the chemical comes from a laboratory or a plant, it pays to be careful and read the label thoroughly.
