Triazole fungicides may potentially harm human health. The 'quick, easy, cheap, effective, rugged, and safe' approach has become popular for extraction and cleanup during pesticide residue analysis. We aimed to (a) validate a method for the simultaneous determination of myclobutanil, penconazole, tebuconazole, and triadimenol in squash using LC-MS/MS and (b) determine the pre-harvest intervals (PHIs) and assess the related risk of consuming squash cultivated under open-field conditions in Saudi Arabia. Using acetonitrile as the extraction solvent and fourfold dilution in deionized water led to weak signal suppression (<À6.1%). The limits of quantitation ranged from 10 to 40 μg/kg. Mean recovery and relative standard deviation ranged from 81.7 to 96.3% and from 3.6 to 11.4%. The half-lives ranged from 2.22 to 3.83 days, and the dissipation followed first-order kinetics. The terminal residues of myclobutanil, penconazole, tebuconazole, and triadimenol were <0.771, <0.307, <0.459, and <0.954 mg/kg, respectively, 7 days after two or three applications of recommended dosages. The PHIs of 7. 1-11.4, 8.7-13.1, 3.8-5.3, and 11.3-14.3 days are suggested after the application of the recommended dose and double the recommended dose. A consumer risk assessment based on estimated dietary intake indicated that the consumption of squash treated with the recommended doses does not pose a significant health risk. K E Y W O R D S dissipation kinetics, LC-MS/MS, risk assessment, squash, triazole fungicides 1 | INTRODUCTION Squash (Cucurbita sp.)-a rich source of nutrients such as carbohydrates, vitamins, and minerals (Roura et al., 2004)-is a major crop in Saudi Arabia, where the plants are cultivated under open-field and greenhouse conditions (FAOSTAT, 2018). Squash and other cucurbit plants are susceptible to powdery mildew disease, which is mainly caused by the fungus Podosphaera xanthii. In severe cases, powdery mildew can cause premature death of the leaves and reduce squash production over the long term (Velkov & Masheva, 2002).At present, powdery mildew infections of squash leaves are routinely treated with the triazole fungicides myclobutanil, penconazole, tebuconazole, and triadimenol (Figure 1). Triazoles are inhibitors of demethylation that disrupt the biosynthesis of fungal cell
