kresoxim-methyl and fludioxonil

The residue distribution and dissipation of pyrimethanil, fludioxonil, cyprodinil, and kresoxim-methyl, which were introduced during postharvest waxing treatments of apples, were investigated. In addition, different residue removal methods were tested for the four fungicides in apples, and the removal efficiencies were compared. A multiresidue analytical method was developed based on quick, easy, cheap, effective, rugged, and safe method (QuEChERS) for the determination of the fungicide residues in apples. The dissipation study demonstrated that there was no significant change of fungicide residue magnitude during a 40-day storage process under ambient temperature. The fungicide residues in apples by wax treatment were shown to be very much stable. The results of residue distribution study demonstrated that waxing treatment may help to reduce the risk of pesticide when only the pulp was consumed. In the residue removal study, results suggested that higher temperature and the addition of acetic acid can improve the residue removal efficiency.

Topics: Dioxoles; Food Contamination; Food Handling; Fruit; Fungicides, Industrial; Malus; Pesticide Residues; Pyrimidines; Pyrroles; Strobilurins

Although there is some evidence regarding the effect of solarization and biosolarization on pesticide degradation, information is still scarce. The aim of this study was to determine the effect of these disinfection techniques on the degradation of eight fungicides (azoxystrobin, kresoxin methyl, tebuconazole, hexaconazole, triadimenol, cyprodinil, pyrimethanil and fludioxonil) commonly used in pepper crops under greenhouse cultivation. Seventy-five 17-L pots filled with clay-loam soil were placed in a greenhouse during the summer season and then contaminated with the studied fungicides. Treatments consisted of different disinfection treatments, including a control without disinfection, solarization and biosolarization. For the solarization and biosolarization treatments, low-density polyethylene film was used as cover. Five pots per treatment were sampled periodically up to 90d after the beginning of each treatment and fungicide residues were analyzed by GC/MS. The results showed that both solarization and biosolarization enhanced fungicide dissipation rates with regard to the control treatment, an effect which was attributed to the increased soil temperature. Most of the fungicides studied showed similar behavior under solarization and biosolarization conditions. However, triadimenol was degraded to a greater extent in the biosolarization than in the solarization treatment, while fludioxonil behaved in the opposite way. The results confirm that both solarization and biosolarization contribute to pesticide dissipation and can therefore be considered alongside other soil disinfection techniques, as a bioremediation tool for pesticide-polluted soils.

Topics: Dioxoles; Environmental Restoration and Remediation; Fungicides, Industrial; Hot Temperature; Methacrylates; Phenylacetates; Photochemical Processes; Pyrimidines; Pyrroles; Soil; Soil Pollutants; Strobilurins; Triazoles

To overcome fludioxonil resistance of Penicillium expansum, a mycotoxigenic fungal pathogen causing postharvest decay in apple, by using natural phenolic chemosensitizing agents.. Fludioxonil-resistant mutants of P. expansum were co-treated with different oxidising and natural phenolic agents. Resistance was overcome by natural phenolic chemosensitizing agents targeting the oxidative stress-response pathway. These agents also augmented effectiveness of the fungicide, kresoxim-methyl. Results indicated that alkyl gallates target mitochondrial respiration and/or its antioxidation system. Fungal mitochondrial superoxide dismutase (Mn-SOD) plays a protective role against alkyl gallates.. Natural chemosensitizing agents targeting the oxidative stress-response system, such as Mn-SOD, can synergize commercial fungicides.. Redox-active compounds can serve as potent chemosensitizing agents to overcome resistance and lower effective dosages of fungicides. This can reduce costs with coincidental lowering of environmental and health risks.

Topics: Antifungal Agents; Dioxoles; Drug Interactions; Drug Resistance, Fungal; Fungal Proteins; Malus; Metabolic Networks and Pathways; Methacrylates; Mitochondria; Mitochondrial Proteins; Oxidants; Oxidative Stress; Penicillium; Phenols; Phenylacetates; Pyrroles; Strobilurins; Superoxide Dismutase