XIE Xuewen, CHUAI Hongyun, LI Lei, CHAI Ali, SHI Yanxia, LI Baoju. Deposition distribution and dissipation dynamics of 10% diethofencarb + procymidone micropowder in facility cucumber[J]. Chinese Journal of Pesticide Science, 2020, 22(2): 378-387. DOI: 10.16801/j.issn.1008-7303.2020.0068
    Citation: XIE Xuewen, CHUAI Hongyun, LI Lei, CHAI Ali, SHI Yanxia, LI Baoju. Deposition distribution and dissipation dynamics of 10% diethofencarb + procymidone micropowder in facility cucumber[J]. Chinese Journal of Pesticide Science, 2020, 22(2): 378-387. DOI: 10.16801/j.issn.1008-7303.2020.0068

    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.
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