Agriculture Reference
In-Depth Information
So a semisynthetic pyrethrin spray combined with piperonyl
butoxide would require less poison to be used and be more
effective, and the type of pyrethrin being used would be less
toxic to humans.
23
According to a metabolic study, neither natural nor synthetic
pyrethrins accumulate in the body or show up in breast milk
because they are quickly detoxified in the human body.
24
Any allethrin consumed by a human is rapidly transformed
into something less toxic and eliminated.
25
In addition,
allethrin is broken down into nontoxic compounds through
the action of air and sunlight within a few days,
26
though not
as quickly as natural pyrethrin.
The piperonyl butoxide used to increase the effectiveness of
pyrethrins is a semisynthetic derivative of safrole—an oil
found in the bark of sassafras trees. It works by inhibiting
enzymes that detoxify the pyrethrins in the insect's body.
Safrole is a known carcinogen, but the status of piperonyl
butoxide as a carcinogen is disputed. Unlike allethrin,
piperonyl butoxide is stable in the environment and doesn't
break down easily.
27
Given current information, the allethrin doesn't worry me
much, but I am sufficiently uneasy about the persistence of
piperonyl butoxide in the environment that I wouldn't
personally use it. Either way, synthetic pyrethrins and those
containing piperonyl butoxide should be used according to
label directions and never be used on crops within a week of
harvest; even then harvested crops should be well washed.
Carbaryl (also known as “Sevin”) is another common
synthetic insecticide used in home gardens. There is no clear
