Dissipation of Ethion Applied on Greenhouse Cucumbers by Duration of a Pre-harvest Interval (PHI)

In this study, Residues of ethion were estimated in cucumber by gas chromatography following three applications of the insecticide at 375 and 750 g a.i. ha−1. Analysis was carried out by the QuEChERS method, using gas chromatographynitrogen phosphor detection (GC-NPD), with obtained recoveries greater than 80%. The average initial deposits of ethion on cucumber fruits were found to be 2.40 and 4.97 mg kg−1 at single and double dosages, respectively. Residue levels in samples, which were collected post application of the pesticide throughout a period of 15 days showed a gradual and significant (p<0.05) decrease in contents for ethion. Residues of ethion dissipated below the maximum residue limit (MRL) of 0.5 mg kg−1 in 7 days. Half-life (T½) for degradation of ethion on cucumber was observed to be 2.1 and 1.8 at single and double dosages, respectively. A waiting period of 7 days is suggested for safe consumption of cucumber.