Neurotoxicity of diallate and triallate when administered orally or topically to hens.

Two allylthiocarbamate herbicides, diallate and triallate, were evaluated for neurotoxicity by oral and topical dosing studies with mature white leghorn hens. Diallate was tolerated for 90 days at topical doses of 40 mg/kg/day and oral doses of 20 mg/kg/day. Reversible ataxia and narcosis occurred at diallate doses of 80 mg/kg/day and higher by either route of administration. Triallate did not elicit signs of neurotoxicity at 300 mg/kg/day topically or 400 mg/kg/day orally. The oral dose, however, resulted in gastrointestinal irritation and severe weight loss, such that dosing was terminated after 25 days. Triallate was tolerated at oral dosages of 90 mg/kg/day and topical doses up to 330 mg/kg/day.