Cymoxanil is a fungicide that is highly soluble in water and considered quite volatile. It has a low potential for leaching to groundwater, is non persistent in soil and water systems.Cymoxanil is moderately toxic to mammals, may cause adverse effects on reproduction/development and has a high potential to bio-concentrate. It is moderately toxic to most aquatic organisms, earthworms and honeybees but less so to birds.

Use

Cymoxanil is applied as a seed treatment to cut potato seed pieces or as a foliar application to the plants to control late blight (Phytophthora infestans). The end-use product, Curate 60 DF is formulated as a 60% dry flowable formulation. Curate 60 DF is to be used only in combination (tank mixed) with other protectant fungicides such as mancozeb, chlorothalonil, triphenyltin hydroxide, or metiram. As a seed treatment,cymoxanil is applied by dipping the seed pieces in a concentrated slurry or by mist seed treating equipment.

Toxicity

Acute Toxicity

The acute toxicity data show that cymoxanil is not acutely toxic by the oral, inhalation, and dermal routes of exposure.

Chronic Toxicity

In a combined chronic/carcinogenicity study, the NOEL was 4.08 mg/kg/day for males and 5.36 mg/kg/day of females. In a chronic toxicity study in dogs, the NOEL was 5.7 mg/kg/day for males and 3.1 mg/kg/day for females. Carcinogenicity: Cymoxanil showed no evidence of carcinogenic potential and was classified as a “Not Likely” carcinogen.

Metabolism

In the rat metabolism study, radioactive cymoxanil administered by gavage as a single dose was readily absorbed through the intestines. The majority of the dose was excreted in the urine and to a lesser extent in the feces. The principal pathway for elimination of cymoxanil is via renal elimination. The proposed metabolic pathway involves hydrolysis of cymoxanil and then degradation to glycine, which is incorporated into natural constituents or further metabolized. Hydrolysis and subsequent glucuronide conjugation is proposed as the major metabolic pathway.