百菌清、腈菌唑在香蕉上的残留动态

Analysis of the residual dynamics of chlorothalonil and myclobutanil in bananas

为了科学、安全地使用百菌清、腈菌唑防治香蕉病害,采用气相色谱法及田间试验方法研究百菌清、腈菌唑在香蕉上的残留消解动态。结果表明,百菌清在香蕉上的原始沉积量大于腈菌唑,同一农药的原始沉积量与施用量密切相关。百菌清施药后14 d内的消解率大于腈菌唑,而14～21 d的消解率与腈菌唑接近。百菌清、腈菌唑在香蕉上的残留消解规律符合一级动力学关系,相关系数|r|=0.942 8～0.998 0(P<0.1)。百菌清的消解速度较快,消解系数|κ|=0.220 45±0.009 15,半衰期(T_(1/2))为3.1～3.3 d,消解99%所需要的时间(T_(0.99))为20.1～21.7 d;腈菌唑的消解速度缓慢,|κ|=0.170 3±0.000 1,T_(1/2)为4.1 d,T_(0.99)为27.1 d。距第2次(末次)施药后55～68d,在香蕉产品上均未检出百菌清、腈菌唑残留。

The thesis is entitled to make clear the residual dynamic of chlorothalonil and myclobutanil in bananas in hoping to control the likely disease in the fruit trees. As a kind of main tropic and sub-tropic fruit growing in Zhangzhou, Fujian, bananas should be protected from being harmed by the drug-residuals like chlorothalonil and myclobutanil. For this purpose, we have studied the residual dynamics of chlorothalonil and myclobutanil in bananas by using a method of GC and field experiment. Results of our studies indicated that the methods here used were simple and convenient. The analysis of samples can satisfy the actual needs when we determine the residue of chlorothalonil with GB/T 5009.105—2003 and myclobutanil with GB/T 5009.146—2003. The original sediment of chlorothalonil in bananas had been found more than that of myclobutanil, which was closely related to their application dosage for the same pesticide. On the other hand, chlorothalonil proved to be faster dissipated than myclobutanil during the first 14d after application, with their dissipation rate going up to the almost same level 14 d to 21 d later. In addition, the dissipation of chlorothalonil and myclobutanil in bananas proved to be well fitted by the first-order kinetics, with the correlation coefficient standing between 0.942 8 to 0.998 0 （p〈0.01）. The experimental results also showed that the degradation coefficient （︱k︱） of chlorothalonil was 0.220 45±0.009 15, with T1/2 being in a range from 3.1 d to 3.3 d, while T0.99 in a range from 20.1 d to 21.7 d. On the contrary, myclobutanil had the︱k︱, T1/2 and T0.99 parameters of myclobutanil of 0.170 3±0.000 1, 4.1 d and 27.1 d , respectively. Therefore, the chlorothalonil and myclobutanil residues in the banana could hardly be detected 55-68 d after the second application.