MANAGEMENT OF LOOSE SMUT DISEASE (USTILAGO TRITICI) AND DETERMINATION OF FUNGICIDES RESIDUES IN WHEAT MATRICES USING QuEChERS METHODOLOGY

Abstract

Loose smut of wheat caused by Ustilago tritici is a disease of economic important in Egypt. It is an exclusively seedborne disease and can be controlled by applying pre-sowing dry seed treatment with any of the nature products as black seed oil and cumin oil or gamma rays@ 150, 200, 250 Gy or four systemic fungicides as Premis® 25% FS, Sumi-8® 2%WP, Dividend Extreme® 11.5% FS and Raxil® 2% DS. The present study was carried out during 2016/2017 and 2017/2018 growing seasons and aimed to evolve an efficient method of application of fungicides, nature products and radiation for an economic control of loose smut of wheat and also evaluated for the determination of four azole fungicides residues in wheat and soil samples. The tested fungicides were highly effective in controlling the disease and gave more than 98% disease control with high grain yield while nature products as black seed oil and cumin oil gave 61.2% and 56.6% control, respectively. For determining the fungicides residues, the fungicides were extracted and cleaned using the ‘Quick Easy Cheap Effective Rugged and Safe’ (QuEChERS) method and followed by gas chromatographs coupled to electron capture (µECD) detector analysis. The analytical method was evaluated in terms of recoveries, repeatability, limit of quantitation (LOQ) and matrix effects. The recoveries were between 80.12 to 97.85% with relative standard deviation (RSDs) ranged between 6.12-10.65%. Limit of detections ranged from 0.002 to 0.01mg/kg. LOQ for tested fungicides less than or met the maximum residue limits (MRL).