Residues of Fungicides and Insecticides in Rice Field

Abstract

The use of pesticides assists in integrated programs that aim high yield and quality grains in irrigated rice (Oryza sativa L.). However, the use of pesticides can pose risk to rice quality as well as the environment and general population. Therefore, the objective of this study was to investigate the dissipation and persistence of fungicides (azoxystrobin and difenoconazole) and the insecticides (lambda‐cyhalothrin and thiamethoxam) in irrigation water, soil, rice plant, panicle, and rice grain. The study was conducted in the field during the 2011/2012 crop season, with fungicides and insecticides applied to the aerial parts of the rice plants, the samples were collected in different moments during a 40‐d monitoring period after the application of the pesticides. Laboratory analyses to detect pesticide residues were determined by ultra‐high performance liquid chromatography and by gas chromatography. Pesticide residues were detected in irrigation water and rice plants during the 40 d of monitoring. Azoxystrobin, difenoconazole, and thiamethoxan were transported into the environment due to overflowed water from the rice field, however pesticide residues were not detected in soil. Azoxystrobin, difenoconazole, thiamethoxan, and lambda‐cyhalothrin residues were detected in rice hull, however, no residues were detected in neither brown nor polished rice grain.