10％乙霉威·腐霉利微粉剂在设施黄瓜上的沉积分布及残留消解动态

为探究10%乙霉威·腐霉利微粉剂(有效成分质量分数:5%乙霉威,5%腐霉利)在设施黄瓜上施用后的沉积分布特性及残留消解动态,采用PC-3A(S)型激光粉尘仪及粉尘取样片,分别研究了不同设施类型、不同温湿度及不同施药角度下,10%乙霉威·腐霉利微粉剂在设施黄瓜上的沉积分布情况;并于2017年和2018年,分别在北京市进行了该药剂在设施黄瓜叶片和果实中的残留及消解动态试验。结果表明:不同设施类型、不同温度条件下,10%乙霉威·腐霉利微粉剂的沉积分布特性无明显差异,且其有效成分分解率不受温度影响;不同湿度条件下,该微粉剂在黄瓜叶片上的沉积量不同,湿度越大沉积量越多。乙霉威和腐霉利在黄瓜叶片和果实中的消解动态均符合准一级动力学或一级动力学方程,2种药剂在叶片中的半衰期分别为3.2 d和3.0~3.2 d,在果实中的半衰期分别为4.0~4.3 d和3.1~3.8 d。采用10%乙霉威·腐霉利微粉剂,分别按100 g/hm2和150 g/hm2(1.5倍)剂量于黄瓜幼果期施药,最多施药3次,施药间隔期为7 d,距最后一次施药间隔7、10和14 d分别采样,乙霉威在黄瓜果实中的最大残留量为0.88 mg/kg,低于中国国家标准规定的其最大残留限量(MRL)值(5 mg/kg),腐霉利在黄瓜果实中的最大残留量为0.49 mg/kg,也低于其MRL值(2 mg/kg)。该研究结果可为10%乙霉威·腐霉利微粉剂在设施黄瓜上的安全使用提供数据支持。

Deposition distribution and dissipation dynamics of 10% diethofencarb + procymidone micropowder in facility cucumber

The deposition distribution characteristics and the dynamics of residual dissipation of 10% diethofencarb + procymidone micropowder (5% diethofencarb, 5% procymidone) was investigated on facility cucumbers. The PC-3A(S) laser dust meter and dust sample piece were used to study the distribution of deposition when the different types of facilities, different temperature and humidity, and different application angles of 10% diethofencarb + procymidone micropowder were applied on the facilities cucumber. The residue dissipation dynamic tests were conducted on facilities cucumber leaves and fruits from 2017 to 2018 in Beijing. The results showed that there was no significant difference in the deposition distribution characteristics of 10% diethofencarb + procymidone micropowder when different facilities or different temperature conditions were applied. The deposition rate of active ingredients was not influenced by temperature. However, under different humidity conditions, the deposition amount of the micronizer on cucumber leaves was different. Their half-lives in leaves and fruits were 3.2 d and 3.0-3.2 d, respectively. And half-lives in fruits were 4.0-4.3 d and 3.1-3.8 d, respectively. 10% diethofencarb + procymidone micropowder was applied to cucumber at the fruit stage at the dosage of 100 g/hm2 and 150 g/hm2 (1.5 times), and the maximum application time was 3 times. The sampling time was 7, 10 and 14 days from the last application. The maximum residue of diethofencarb in cucumber fruit was 0.88 mg/kg, which was lower than the MRL (5 mg/kg) stipulated by Chinese national standard. The maximum residue of procymidone in cucumber fruit is 0.49 mg/kg, which is lower than the MRL (2 mg/kg) in China. This study will contribute to the safe use of 10% diethofencarb + procymidone micropowder in cucumber.