Agriculture Reference
In-Depth Information
sations rarely persist more than 24 hours. Little or no inflammatory reaction
is apparent where the paresthesia are reported; the effect is presumed to result
from pyrethroid contact with sensory nerve endings in the skin. Not all pyre-
throids cause a marked paresthetic reaction; it is prominent following exposure
to pyrethroids whose structures include cyano-groups: fenvalerate, flucythri-
nate, cypermethrin, and fluvalinate. The paresthetic reaction is not allergic in
nature: sensitization does not occur. Neither race, skin type, nor disposition
to allergic disease affect the likelihood or severity of the reaction.
Persons treated with permethrin for lice or flea infestations sometimes ex-
perience itching and burning at the site of application, but this is chiefly an
exacerbation of sensations caused by the parasites themselves, and is not typi-
cal of the paresthetic reaction described above.
The manifestations of neurologic disorder seen in laboratory animals
given the more toxic pyrethroids in large doses are salivation, irritability,
tremors, ataxia, choreoathetosis (writhing convulsions), fall in blood pressure,
and death. Severe metabolic acidosis is characteristic.
Due to the inclusion of unique solvent ingredients, certain formulations
of fluvalinate are corrosive to the eyes.
Pyrethroids are not cholinesterase inhibitors.
2.
Antibiotics
Antibiotics are natural products derived from fungi or bacteria with anti-
bacterial activity. A new group of products derived from the fermentation of
Streptomyces
avermitilis
. The products (a mixture of the fermentation) is
abamectin, the common name for products such as Avermectin
, Affirm
, or
and Avid
.
Toxicology and Mode of Action
These products containing abamectin are effective against nematodes, and
insects, ticks and mites.
The mode of action has been shown to be the blocking of the neuro-
transmitter gamma aminobutyric acid (GABA) at the neuromuscular junctions
of insects and mites.
3.
Insecticidal Soaps
These soaps are the alkali salts of fatty acids. These soaps can be made
from potassium, sodium, or ammonia.
Toxicology and Mode of Action
The mode of action of these fatty acid salts is the reduction of surface ten-
sion of water which allows water to penetrate the insect spiracles and reduce
the oxygen availability leading to suffocation and death. These products are
