Dissipation rates of insecticides and fungicides in peppers grown in greenhouse and under cold storage conditions

The dissipation of three insecticides (pirimicarb, pyriproxyfen and buprofezin) and three fungicides (cyprodinil, fludioxonil and tebuconazole) in peppers was evaluated in a study carried out on an experimental greenhouse. Pepper samples were collected during 6 week period in which two successive applications of these pesticides were performed. Gas chromatography (GC) with nitrogen–phosphorus detection (NPD) was used to study the disappearance of these compounds in peppers. Confirmation analysis of pesticides was carried out by capillary gas chromatography coupled with mass spectrometry in the selected ion monitoring (SIM) mode. At the preharvest interval the residue levels were below the legal limit established in Spain. The disappearance rates of these compounds on peppers were described as pseudo-first-order kinetics (r between 0.953 and 0.997) and half-life in the range of 4.41 and 21.47 days. After thirty days under cold and darkness storage conditions, dissipation of buprofezin and pyriproxyfen were not observed. However, dissipation rate in pepper of pirimicarb cyprodinil, fludioxonil and tebuconazole in refrigerated were observed. This, the half-lives for these pesticides were 5–9 times greater under refrigeration.