배추中 cyanofenphos의 잔류소장(殘留消長)을 재배시기(栽培時期)를 달리하여 조사(調査)하였다. 배추 이식후(移植後) 22일(日)과 36일(日)에 cyanofenphos 25EC를 0.5와 0.75㎏ AI/㏊의 비율(比率)로 각각 살포(各各 撒布)하고 최종살포후(最終撒布後) 35일(日)까지 잔류량(殘留量)을 조사(調査)한 결과(結果), cyanofenphos의 분해양상(分解樣相)은 재배시기(栽培時期)와는 무관(無關)하게 양약량수준(兩藥量水準)에서 비슷한 경향(傾向)을 보였다. 즉 최종살포후(最終撒布後) 14일(日)까지는 배추중(中) cyanofenphos가 급격(急激)히 감소(減少)하였으나 그 후로는 비교적 서서(比較的 徐徐)히 감소(減少)하였다. 배추중(中) cyanofenphos의 반감기(半減期)는 $6{sim}7$일(日)이었으며, 살포시기(撤布時期)와 살포율(撒布率)에 따른 차리(差異)는 별로 없었다. 양(洋)배추중(中) cyanofenphos의 잔류허용량(殘留許容量)인 2ppm을 기준(基準)하여 볼때, 수확전 살포일(收穫前 撒布日)은 0.5와 0.75㎏ AI/㏊에서 각각(各各) 16, 17일(日)로 추정된다.
Persistence of cyanofenphos on Chinese cabbage under the different climate conditions was studied by spraying the insecticide at the rate of 0.5 and 0.75 ㎏ AI/ha at 22 and 36 days after transplanting and monitoring its residues upto 35 days after the final spray. At both spraying rates the degradation patterns of the insecticide, regardless of climate condition, showed similar trends; cyanofenphos residues on Chinese cabbage declined rapidly upto 14 days after the final spray but more slowly thereafter. Half-life for cyanofenphos on Chinese cabbage was $6{sim}7$ days. The half-life was little affected by the spraying rate and time. Based on the FAO/WHO maximum residue limit of cyanofenphos on common cabbage (2 ppm), it is recommended that the pre-harvest intervels of the insecticide on Chinese cabbage could be 16 and 19 days for 0.5 and 0.75 ㎏ AI/ha, respectively.
