Agriculture Reference
In-Depth Information
Table 5.7
continued
Active Ingredients
Product Trade Names
deltamethrin
Decamethrin, Decis
dimethrin,
esfenvalerate
Asana
fenpropathrin
Danitol, Herald, Meothrin, Ortho Danitol, Rody
fenvalerate
Belmark, Fenkill, Pydrin, Sumicidin, Tribute
flucythrinate
AASTAR, Pay-off
fluvalinate
Mavrik, Mavrik Aquaflow, Spur
furethrin,
indothrin,
permethrin
Ambush, BW-21-Z, Ectiban, Eksmin, Kafil, Permasect,
Perthrine, Pounce, Pramex, Outflank, Talcord, Tor
phthalthrin
Neopynamin
resmethrin
Benzofuroline, Chrysron, Pynosect, Synthrin
tetramethrin
Neopynamin, Phthalthrin
tralomethrin
Scout
Pyrethroids are formulated as emulsifiable concentrates, wettable powders,
granules, and concentrates for ultralow volume application. They may be
combined with additional pesticides (sometimes highly toxic) in the technical
product or tank mixed with other pesticides at the time of application. AAS-
TAR is a combination of flucythrinate and phorate. Phorate is a highly toxic
organophosphate.
Nix is a 1% permethrin creme applied to control human ectoparasites.
Toxicology and Mode of Action
Although certain pyrethroids exhibit striking neurotoxicity in laboratory
animals when administered by intravenous injection, and some are toxic by the
oral route, systemic toxicity by inhalation and dermal absorption is low.
There have been very few systemic poisonings of humans by pyrethroids.
Although limited absorption may account for the low toxicity of some pyre-
throids, rapid biodegradation by mammalian liver enzymes (ester hydrolysis
and oxidation) is probably the major factor responsible. Most pyrethroid me-
tabolites are promptly excreted, at least in part, by the kidney.
Extraordinarily high-absorbed doses may rarely cause incoordination,
tremor, salivation, vomiting, diarrhea, and irritability to sound and touch.
Extreme doses have caused convulsions in laboratory animals.
Apart from systemic neurotoxicity, some pyrethroids do cause distressing
paresthesia (abnormal sensations) when liquid or volatilized materials contact
human skin. Sensations are described as stinging, burning, itching, and tin-
gling, progressing to numbness. The skin of the face seems to be most
commonly affected, but the hands, forearms, and neck are sometimes involved.
Sweating, exposure to sun or heat, and application of water enhance the disa-
greeable sensations. Sometimes the effect is noted within minutes of expo-
sure, but a 1-2 hour delay in appearance of symptoms is more common. Sen-
