Deposition and dissipation of difenoconazole in pepper and soil and its reduced application to control pepper anthracnose

The initial deposition amount, dissipation dynamics, retention rate, and field control efficacy of difenoconazole in pepper-soil system were studied with different application dosages, planting regions and patterns. The initial deposition amount of difenoconazole under the same application dosage showed the following order: fruits < cultivated soils < lower stems < upper stems < lower leaves < upper leaves, open field < greenhouse, and Changjiang < Cixi < Hefei < Langfang, respectively, which increased with increasing application dosage. The dissipation rates in leaves, stems, fruits and cultivated soils exhibited an initially fast and then slow trend, while the retention rates displayed a tendency of first increasing and then stabilizing with increasing application dosages. After 7 d of difenoconazole application, the retention rates at five concentrations were 10.3%-39.1%, and the field efficacy mostly reached the minimum effective dose. These results suggested that difenoconazole could be reduced by 25% based on the minimum recommended dose meeting the requirements of field control efficacy for controlling pepper anthracnose.

Automated summary

The study investigated the initial deposition amount, dissipation dynamics, retention rate, and field control efficacy of difenoconazole in pepper-soil system with different application dosages, planting regions, and patterns. The results showed that the initial deposition amount of difenoconazole increased with increasing application dosage and varied among different plant parts, planting regions, and patterns. The dissipation rates exhibited a trend of initially fast and then slow, while the retention rates increased initially and then stabilized with increasing application dosages. The field efficacy mostly reached the minimum effective dose after 7 days of difenoconazole application.