The control effect of pyridaben against cotton mite and its dissipation and residue behavior under field conditions

The present study was undertaken to value the deposition and persistence of pyridaben and its control effect on mites in cotton field. A simple and reliable analysis method was involved by coupling HPLC with QuChERS pretreatment for the detection of pyridaben in cotton plant and soil samples taken from Xinjiang and Shandong, the two representative cotton-planting areas in China. At the fortified levels of 0.1-10.0 mg L-1, the recoveries ranged from 86.33 to 106.50% and RSD 0.48-2.34%. During 14 days intervals, the fast dissipation rate of pyridaben was embodied in cotton leaves from Xinjiang with the half-lives 2.12-2.31 days and Shandong with the half-lives 1.66-1.78 days, respectively. The half-lives of pyridaben in soils were slower than those in cotton leaves ranging from 3.43 to 3.82 days in Xinjiang and 3.00-3.27 days in Shandong, respectively. The initial deposition was not affected by the spraying times for the complete degradation of pyridaben. Two formulations demonstrated a slight distinction between the dissipation behavior with half-lives 1.66-1.78 days of EC (emulsifiable concentrate) and 1.93-1.97 days of WP (wettable powder), respectively. The control effects of cotton mites was determined up to 80% at 14 days after application (recommended label use), which suggested that the recommended application of pyridaben on cotton was rational from the view of crop protection and environmental safety.

Automated summary

This study evaluated the deposition and persistence of pyridaben in cotton fields, as well as its control effect on mites. Pyridaben dissipated faster in cotton leaves from Xinjiang and Shandong compared to soil, with slight variations between formulations. The initial deposition did not affect the complete degradation of pyridaben. The control effect on cotton mites was up to 80% at 14 days after application, indicating the rational use of pyridaben for crop protection and environmental safety.