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Gypsy moth (Lymantria dispar (L.) is one of most important defoliating pests of deciduous trees. Due to increased environmental demands, the use of plant-based preparations is gaining in importance as a control option for this pest in forestry, agriculture and horticulture. The aim of this study was to evaluate antifeeding and insecticidal activity of 0.5, 1 and 2% extracts of Ailanthus altissima bark and leaves, and Morus alba leaves, against L. dispar larvae under laboratory conditions. Antioxidant capacity of plant extracts was determined, as well as the content of phenolic compounds by spectrophotometric and HPLC-DAD methods. Antifeeding and insecticidal effects were tested in a "no-choice" test. The highest content of all bioactive phenolic compounds was in A. altissima bark and M. alba leaf extracts. The lowest leaf consumption after 24 and 48 h was in A. аltissima bark (5.03, 9.30%, respectively) and M. alba leaf (1.44, 3.22%, respectively) extracts. A. altissima bark and M. alba leaf extracts expressed strong antifeeding activity. After 24 h, all extracts expressed slight insecticidal effect (2.25-17.50% of mortality). The mortality increased after 48 h in treatments with A. altissima bark extract, at all applied concentrations (40.0-57.50%) and M. alba leaves at 1 and 2% concentrations (30.0-62.50%). Our results indicate that extracts of A. altissima bark and M. alba leaves may act as effective low-cost natural protectants able to control the presence of gypsy moth in ecosystems. Extracts of A. altissima bark and M. alba leaves expressed strong antifeeding activity and significant insecticidal effect on gypsy moth larvae, at all applied concentrations.

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.

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Summary: Decline of pear trees in the region of Čačak (Serbia)