SuMMARYChlorpyrifos is a hazardous insecticide and important pollutant of the environment. The EU Directive 2008/105/EC lists it as one of the priority water pollutants. Its presence is mainly detected by chemical methods but, since biological tests have gained in importance in the last few years, this study aimed to assess the potentials of white mustard (Sinapis alba L.) and maize (Zea mays L.) as indicators of water pollution. The phytotoxic effects of chlorpyrifos (rates 0.05-10µg a.i./l) were assessed based on physiological (germination energy and germination) and morphological traits (root and shoot length, fresh and dry weights) of the tested species. A slightly modified filter paper method was used and the results were processed by Duncan`s multiple range test and Probit analysis (EC 50 ). According to the Directive, the maximal allowable concentration (MAC) of chlorpyrifos in water is 0.1µg a.i./l. When applied at the MAC value, chlorpyrifos inhibited germination energy and germination (11.25%) of white mustard, as compared to the control (91.5; 93.5%), and its hypocotyls and epicotyls failed to form. At the rates 50% below the MAC, germination energy and germination (87.75; 88.25%) were significanty inhibited, as well as root and shoot growth of seedlings. Chlorpyrofos did not affect the germination energy and germination of maize, while all morphological traits were significantly reduced by chlorpyrifos at the MAC rate. The EC 50 of chlorpyrifos was 0.09µg a.i./l for germination of white mustard and 3.21µg a.i./l for maize.

SUMMARYLymantria dispar L. is the most devastating polyphagous pest of deciduous forests, orchards and urban greenery. To prevent damages that L. dispar larvae cause in forestry, agriculture and horticulture, mechanical measures and the use of biological insecticides are the most frequently applied practices. However, the use of conventional insecticides is inevitable in crop protection and forest management on smaller areas, especially in gradation years. However, inadequate use of these chemicals has led to disturbance of biocoenotic balance, outbreaks of some previously less harmful organisms and pesticide residues in soil and watercourses in some regions. To mitigate these consequences it is necessary to harmonize L. dispar control with integrated management principles by applying selective and less toxic insecticides. Therefore, the potential of botanical insecticides and antifeeding substances is gaining in importance. The aim of this study was to assess the influence of ethanol extracts (1, 2 and 5%) of Ambrosia artemisiifolia L., Erigeron canadensis L., Daucus carota L., Morus alba L. and Aesculus hippocastanum L. on the feeding intensity of L. dispar larvae, i.e. to evaluate their antifeeding activity under the conditions of "no-choice" test. Ten larvae per repetition were placed in Petri dishes and offered oak leaf slices (2 x 9 cm 2 /repetition) previously dipped in plant extract or ethanol (1, 2, and 5%) for the control. Feeding intensity, expressed as a percentage of consumed leaf area (%), was measured after 48 h. For assessing the antifeeding activity of plant extracts AFI was calculated and the extracts were classified according to scale: no antifeeding activity, slight antifeeding activity, moderate antifeeding activity and strong antifeeding activity. Data were analyzed using a two-way ANOVA and Duncan`s multiple range test. The results indicate that plant species, i.e. the origin of extracts, had a significant influence on the feeding intensity of L. dispar larvae, while concentration and interaction (plant species x concentration) were not factors of influence. Ae. hippocastanum and M. alba extracts significantly reduced the consumed leaf area (6.24, 18.93%, respectively), compared to the control (97.59%), while the extract of D. carota had a phagostimulative effect (98.88%). Based on AFI values, Ae. hippocastanum extract (87. 10-89.05%) had a strong antifeeding activity, and M. alba medium-to-strong (64.33-71.37%).

SUMMARYDegradation of acetamiprid in sweet cherry samples was evaluated at several intervals from the product application until the end of the pre-harvest interval. An orchard of sweet cherries located at Stepanovićevo village near Novi Sad was used in this study. Acetamiprid was applied according to the manufacturer's recommendation for protecting sweet cherries from their most important pests. Sweet cherry fruit samples were collected at eight intervals: immediately after acetamiprid application and 2, 4, 6, 8, 10, 12 and 14 days after application. The extraction of acetamiprid from sweet cherry samples was performed using a QuEChERS-based method. Determination was carried out using an HPLC-UV diode array detection system (Agilent 1100, United States) with an Agilent Zorbax Eclipse C18 column (50 mm × 4.6 mm internal diameter, 1.8 µm particle size). The method was subjected to a thorough validation procedure. The recovery data were obtained by spiking blank sweet cherry samples at three concentration levels (0.1-0.3 mg/ kg), yielding 85.4% average recovery. Precision values expressed as relative standard deviation (RSD) were below 1.61% for the intraday precision. Acetamiprid showed linear calibrations from 0.05 to 2.5 µg/ml with correlation coefficient (R 2 ) of 0.995%. The limit of detection and limit of quantification were found to be 5 µg/kg and 14 µg/kg, respectively. The validated method was applied in the analysis of acetamiprid in sweet cherry samples. During the study period, the concentration of acetamiprid decreased from 0.529 mg/kg to 0.111 mg/kg. The content of acetamiprid in sweet cherry samples at the end of the pre-harvest interval was below the maximum permissible level specified by the Serbian and EU MRLs.

Imidacloprid is an insecticide most commonly used on vegetables, potato sugar beet, fruit, cereal, maize and rice. Imidacloprid residue has been determined in spiked onion and in onion samples. Sample preparation consisted of dichlormethane extraction of imidacloprid from onion, followed by purification of the obtained extract on a LC-Florisil disposable cartridge. The HPLC-DAD method bas been developed on reversed-phase for separation of imidacloprid with a mixture of 0.01 M phosphate buffer (pH = 3.15): acetonitrile. Recovery of imidacloprid, repeatability, linearity limit of detection and limit of quantifi-cation have been determined.

No abstract