Antifungal activity of five different essential oils in vapour phase for the control of Colletotrichum gloeosporioides and Lasiodiplodia theobromae in vitro and on mango

Mango fruit has high commercial value; however, major postharvest losses are encountered throughout the supply chain due to postharvest diseases. These results lead to the search for natural fungicide for postharvest diseases control. The antifungal effects of five essential oils (thyme, clove, cinnamon, anise and vitex) were assessed by disc volatilisation method. Thyme oil vapours at 5 μL per Petriplate, and clove and cinnamon oil at 8 μL per Petriplate showed 100% growth inhibition of mango pathogens in vitro. GC/MS analysis of essential oil showed thymol (23.88), o‐cymol (23.88) and terpinolene (23.88) as the major constituents of thyme oil. Clove and cinnamon oils contain 3‐allyl‐2‐methoxyphenol (37.42%) and benzofuran 3‐methyl (17.97%), respectively. Thyme oil as a fumigant at 66.7 μL L^?1 showed a significant (P < 0.05) inhibition on postharvest pathogens of mango fruits stored at 25 °C for 6 days. Results of our study suggest the possibility of using thyme oil as an alternate natural fungicide to manage postharvest diseases in mango.     

Method validation for strobilurin fungicides in cereals and fruit

Strobilurins are a new class of fungicides that are active against a broad spectrum of fungi. In the present work a GC method for analysis of strobilurin fungicides was validated. The method was based on extraction with ethyl acetate/cyclohexane, clean-up by gel permeation chromatography (GPC) and determination of the content by gas chromatography (GC) with electron capture (EC-), nitrogen/phosphorous (NP-), and mass spectrometric (MS-) detection. Three strobilurins, azoxystrobin, kresoxim-methyl and trifloxystrobin were validated on three matrices, wheat, apple and grapes. The validation was based on recovery tests at three or four spiking levels, determined as double determinations and repeated three times (n = 6). The mean recoveries for the three detectors were in the range of 70-114%, and the LODs were between 0.004mg/kg and 0.014mg/kg, for all three strobilurins. The values for repeatability and reproducibility were within the limits for repeatability and reproducibility given by the Horwitz equation. Validation was not accepted for azoxystrobin in grapes on all three detectors and for azoxystrobin in apple for the MS-detector. A comparison of matrix-matched standards versus standards in solvent showed varying differences     

Occurrence of fungicide and insecticide residues in trade samples of leafy vegetables

The aim of this work was to report on a total of 23 fungicides and insecticides residues in 75 green and leafy vegetables (Swiss chards, Spinaches and Lettuces) collected from Ourense (NW Spain) by Spring 2007. The pesticides in the study samples were extracted with acetonitrile; the extracts were then cleaned-up by solid-phase extraction and concentrated before determination by PTV (Programmable Temperature Vaporization Injector) – GC-ITMS. Use of analyte protectants mixtures provided the best results in terms of effective compensation for matrix-induced enhancement effect. Pesticide residues were determined above the maxima residue limits (MRL) in 15 of the 75 analyzed samples, with a total of 18 violations of the MRL (three of the samples did not fulfil with two different pesticide MRL). The highest concentrations of fungicides were found in lettuce (procymidone, 12 mg/kg) and the highest concentrations of insecticides were found in Swiss chard (cypermethrin, 6 mg/kg). More positives for fungicides were detected and at larger concentrations than insecticides, especially for lettuces. Accumulation of pesticides in lettuces is higher than for the other leafy vegetables. The findings of this study pointed to the following recommendation: the need for a monitoring program for residues of iprodione and procymidone, together with cypermethrin, in food crops at the national level.     

Emerging pesticide metabolites in groundwater and surface water as determined by the application of a multimethod for 150 pesticide metabolites

A recently developed multimethod for the determination of 150 pesticide metabolites was exemplarily applied to 58 samples of groundwater and surface water. 37 of these metabolites were detected in at least two samples with a concentration ≥0.025 μg/L. The detected metabolites were ranked according to their concentration and frequency of detection. Findings are clearly dominated by metabolites of chloroacetanilide herbicides, but metabolites of sulfonylurea and thiocarbamate herbicides and other herbicides (dichlobenil) together with metabolites of some fungicides (tolylfluanid, chlorothalonil, trifloxystrobin) were also prominent. A number of 17 of the ranked metabolites are denoted as emerging metabolites because no reports on their previous detection in groundwater or surface water were found. Most of them, however, were correctly predicted to occur in the summary reports of the European pesticide approval process. Median total concentrations of the analysed pesticide metabolites summed up to 0.62 μg/L in groundwater and 0.33 μg/L in surface waters. While the concentration of the individual metabolites is usually low (<0.1 μg/L) the diversity of metabolites found in one sample can be large; between two and six metabolites were detected most frequently (maximum of 12 metabolites). Runoff from urban surfaces was investigated in this study and also here previously undetected pesticide (biocide) metabolites were detected. The emerging pesticide metabolites detected in environmental water samples in this study require more extended monitoring.     

Fungicide effects on ammonium and amino acids of Monastrell grapes

The influence of six fungicides (famoxadone, fenhexamid, fluquinconazole, kresoxim-methyl, quinoxyfen and trifloxystrobin) on the amino acids and ammonium composition of grapes (var. Monastrell) are studied. The treatments were performed under critical agricultural practices (CAP), 6 h before grape collection. The analytical determination of amino acids and ammonium were made using HPLC with a photodiode array detector (DAD), after derivatisation of the sample with diethyl (ethoxymethylene)malonate (DEEMM). The application of fungicides to the vine decreased concentrations of nitrogenous compounds in grapes. Furthermore, the qualitative and quantitative effects on the amino acids in the grapes depended on the type of fungicide used. The fungicides which affected the highest number of amino acids were famoxadone and fenhexamid, while quinoxyfen affected the lowest number of amino acids. Grapes treated with famoxadone contained the lowest concentration of total amino acids.     

Evolution of tebuconazole residues through the winemaking process of Mencía grapes

The removal of tebuconazole residues during the winemaking process, applied initially to red must elaborated from Mencía variety grapes from A.O.C. Valdeorrras (Ourense, N.W. Spain), was studied. Analytical determination of tebuconazole residues in grapes, musts and wines were perfomed by gas chromatography equipped with an ion trap mass spectrometry detector (GC–ITMS). Tebuconazole is retained on the solid matter (cakes and lees) and clarification agent. The eliminated percentage of tebuconazole in the final wine is 86%. The influence of this fungicide on the fermentative activity of Saccharomyces cerevisiae yeast and the Oenococcus oeni was also studied through in vitro assays. Liquid chromatography equipped with triple quadrupole mass spectrometer (LC–MS/MS) was used to determine tebuconazole residues in synthetic must and wine used for in vitro assays. No effect on the alcoholic or malolactic fermentation was observed; and no degradation of tebuconazole originated by these microorganisms was registered.     

Role of lees in wine production: A review

The sometimes contradictory role attributed by scientists to lees in wine production is discussed in this review. Studies dealing with the importance of lees in the natural removal of undesirable compounds from wine, the effect of lees–wine contact on the volatile fraction of wines, the key influence of lees on biogenic amine contents in wines, the interactions between lees and phenolic compounds, and the importance of mannoproteins and lipids released by lees have been critically reviewed. Finally, the present exploitation of lees is also outlined.     

Copper contamination of soil and vegetation in coffee orchards after long-term use of Cu fungicides

The repeated use of Cu fungicides to control coffee berry disease can result in increased Cu content in soils and vegetation and thus raising the pollution levels and a concern for potential effects on human health. Therefore a field survey of coffee orchards of the Kilimanjaro and Arusha regions of Tanzania, where Cu fungicides are frequently used, was conducted to determine the possible Cu contamination of soils and vegetation. Soil samples were collected from 0–5, 5–15 and 15–30 cm depth at a distance of 0.5 m from the trunk of coffee trees. Plant leaf samples of beans and maize crops intercropped with coffee trees as well as leaves of coffee trees, were also collected at the same time and places. Soil and plant samples were collected both from small farms and commercial estates. Copper in the soil samples was extracted with CaCl₂ (CCu), whereas for the total Cu, samples were digested with aqua regia (HNO₃ and HCl(1:3) (ACu)). Plant samples were drying ashed and digested with HNO₃. Copper concentration in the extracted and digested solutions was determined with atomic absorption spectrophotometry. A significant Cu enrichment of the soils was observed and the Cu concentration in the 0–5 cm soil depth was about three times higher than in the 15–30 cm depth. A large variability in the soil Cu concentration between fields of the same farm and within the same orchard was observed. The differences in the total Cu concentration (ACu) between small farms and commercial estates were not statistically significant, but the extractable Cu (CCu) was higher and soil pH was lower in the estates of the Kilimanjaro region than at small farms. The soil organic carbon (SOC) content increased significantly with increasing altitudes, and it was also higher on small farms than on commercial estates. The SOC content showed a close and positive correlation with total Cu. At soil pH below 5.3, the CCu fraction increased steeply. Bean plants from coffee fields showed a high concentration of Cu, suggesting a possible Cu toxicity problem in bean plants. Coffee leaves also showed extremely high Cu concentration.     

实时直接分析质谱用于脐橙杀菌剂结构鉴定

将实时直接分析质谱离子源(Direct Analysis in Real Time,DART)用于脐橙果皮表面未知杀菌剂的结构鉴定,经全扫描与二级质谱分析并与文献标准物质特征离子对比,以及气相色谱-质谱联用测试NIST谱库检索,最终确定该物质为杀菌剂抑霉唑。实时直接分析质谱方法简便快速,不需要复杂的前处理过程,为蔬果杀菌剂种类的结构鉴定提供一种快速简便的方法。     

Cold storage conditions affect the persistence of diphenylamine, folpet and imazalil residues in ‘Pink Lady’ apples

‘Pink Lady^®’ apples (Malus domestica) fruit were harvested at commercial maturity treated with three different agrochemical products, and stored at 1 °C under either air or controlled atmosphere conditions (2.5 kPa O₂ + 3 kPa CO₂ and 1 kPa O₂ + 2 kPa CO₂) for 15 and 28 weeks. Diphenylamine, folpet and imazalil contents in both skin and flesh were simultaneously determined after cold storage plus a simulated marketing period of 1 or 7 days at 20 °C. Results showed that apples stored in 2.5 kPa O₂ + 3 kPa CO₂ retained higher contents of diphenylamine residues in comparison with those stored in 1 kPa O₂ + 2 kPa CO₂ or refrigerated air. Significant differences in imazalil skin contents were found throughout the simulated marketing period at 20 °C after storage for 28 weeks in controlled atmospheres.