Uptake and distribution characteristics of the novel fungicide pyraoxystrobin in cucumber plants

The uptake and distribution characteristics of a novel fungicide, pyraoxystrobin, labeled with (14)C on its pyrazol ring, were investigated in cucumber (Cucumis sativus) seedlings. Foliar applied pyraoxystrobin rapidly penetrated the treated leaf and reached a maximum uptake of 68% after 5 d. The translocation of absorbed (14)C in cucumber seedlings was both acropetal and basipetal. However, over 74% of the absorbed (14)C-pyraoxystrobin remained in the treated leaves. The order of its distribution in the plant was as follows: treated leaf > stalk above the treated leaf > leaves above the treated leaf > stalk below the treated leaf > leaves below the treated leaf > cotyledon > root. Seedlings grown in soils containing bound residues (BR) of pyraoxystrobin revealed that the BRs were not easily absorbed or translocated by the plant. Soil type had a large effect on root uptake, with the highest uptake among the three tested soils from red clay.