Biotic and abiotic degradation of pesticide Dufulin in soils

Abstract

Dufulin is a newly developed antiviral agent (or pesticide) that activates systemic acquired resistance of plants. This pesticide is widely used in China to prevent abroad viral diseases in rice, tobacco and vegetables. In this study, the potential impacts such as soil type, moisture, temperature, and other factors on Dufulin degradation in soil were investigated. Degradation of Dufulin followed the first-order kinetics. The half-life values varied from 2.27 to 150.68 days. The dissipation of Dufulin was greatly affected by soil types, with DT50 (Degradation half time) varying between 17.59, 31.36, and 43.32 days for Eutric Gleysols, Cumulic Anthrosols, and Dystric Regosols, respectively. The elevated moisture accelerated the decay of Dufulin in soil. Degradation of Dufulin increased with temperature and its half-life values ranged from 16.66 to 42.79 days. Sterilization of soils and treatment with H2O2 resulted in a 6- and 8-fold decrease in degradation rates compared to the control, suggesting that Dufulin degradation was largely governed by microbial processes. Under different light spectra, the most effective degradation occurred with 100-W UV light (DT50=2.27 days), followed by 15-W UV light (DT50=8.32 days) and xenon light (DT50=14.26 days). Analysis by liquid chromatography-mass spectroscopy (LC-MS) revealed that 2-amino-4-methylbenzothiazole was one of the major decayed products of Dufulin in soils, suggesting that elimination of diethyl phosphate and 2-fluorobenzaldehyde was most like the degradation pathway of Dufulin in Eutric Gleysols.

Hydrolysis and Photolysis Kinetics, and Identification of Degradation Products of the Novel Bactericide 2-(4-Fluorobenzyl)-5-(Methylsulfonyl)-1,3,4-Oxadiazole in Water

“…The experimental results also demonstrate that the initial concentration of FBEZF only had a slight effect on the degradation rate. Similar results have been reported on the degradation of acephate, dufulin, and monocrotophos [28,29,30].…”

The millimetre-scale distribution of 2,4-D and its degraders drives the fate of 2,4-D at the soil core scale

“…Alletto et al, 2006;Sorensen et al, 2006;Cycon et al, 2011;Wang et al, 2014) but most of these studies were conducted on sieved soil amended homogeneously with chemicals, where conditions were optimal for degraders to be in contact with pesticides. The homogeneous distribution considered in this study can be compared to these works.…”

Changes in the persistence of two phenylurea herbicides in two Mediterranean soils under irrigation with low- and high-quality water: A laboratory approach

“…This pesticide dose is equivalent or even lower than field-recommended doses. After evaporation of the solvent sufficient volume of MQ or WW was added to reach 70% soil water holding capacity (Delgado-Moreno and Ruoss et al, 2011;Wang et al, 2014). The soil was then homogenised by thorough mixing and passed several times through a 2 mm sieve.…”