| Myclobutanil is a kind of triazole fungicide, with the function of protection, curative and systemic trait. As a broad spectrum fungicide, myclobutanil is extremely active against the powdery mildew, rust of grain and blank rot of apple and pear. The residue level of myclobutanil in both wheat and soil need to be evaluated. In this paper two-year-residue-assignment of myclobutanil was carried out in different places. The analytical method was developed for detecting myclobutanil residues in wheat. Residues were extracted with mixture solvents of methanol and water (4:1, V/V), cleaned by neutral alumina column, then detected by gas-chromatography, and quantified by external standard. The minimum detectable amount was 1.5×10-12g. The average recoveries in soil, wheat and kernel were 81.4-106.1%, 74.0-114.7% and 96.6-105.2% respectively; the corresponding RSD was 1.9-9.4%, 3.1-5.0% and 1.7-6.3% respectively. The experiment carried out in Guiyang indicated that the decomposition half-life of myclobutanil (25%, EC) was 32.9 -35.2 d in soil and 3.9 -4.4 d in wheat. The residue level of myclobutanil (25%, EC) in kernel is lower than 0.02 mg/kg (Maximum Residue Limit by EU). Therefore, the 30-60 g.a.i/ha as recommended dosage is safe in Guiyang area.
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