Volatiles of Thymus serpyllum L. were obtained by hydrodistillation (HD), simultaneous hydrodistillation, and extraction (SDE) and static headspace gas chromatography-mass spectrometry analysis (head space [HS]), respectively. Monoterpenes were the most dominant in all 3 techniques (84.8%-94.2%). Essential oil profiles obtained by HD and SDE were similar, with oxygenated monoterpenes being the most abundant (up to 75.4%). In HS volatiles of T. serpyllum monoterpene hydrocarbons strongly dominated (94.2%). The main compounds were α-terpinyl acetate (HD and SDE) and myrcene (HS).

The species complexes of leaf-inhabiting mites on apples were studied on actively cultivated and neglected apple orchards as well as on wild apple trees in Serbia, from 1981 to 2013. Thirty-nine species of 11 families were found on Malus domestica Borkh; 25 species of 6 families were found on Malus sylvestris (L.) Miller and Malus pumila Miller. A complex of 18 phytoseiid and 9 spider mite species was detected. Four phytoseiid and three spider mite species were found in commercial apple orchards, 13 phytoseiid and 5 spider mite species in neglected apple stands, and 12 phytoseiid and 7 spider mite species in forest habitats. Predatory mites Euseius finlandicus (Oudemans) and Amblyseius andersoni (Chant) and spider mites Panonychus ulmi Koch and Amphitetranychus viennensis (Zacher) had the highest constancy of occurrence. Positive and significant (or very significant) association was detected for 16 pairs of species. The pairs of phytoseids-spider mites Amb. andersoni–Pan. ulmi, Amb. andersoni–Tetranychus turkestani Ugarov et Nikolskii, and Typhlodromus (Anthoseius) rhenanus (Oudemans)–Te. turkestani had the highest interspecific association indices. Higher mite diversity was found on wild than on cultivated apples, and higher diversity on neglected than on cultivated apples. The complexes of phytoseiids and spider mites had uniform composition in the cultivated orchards, while their composition in the neglected stands was nonuniform and extremely heterogeneous on the wild apple trees.

The results of a research conducted from 1980 to 2016 of leaf mites of stone fruit trees (Prunus spp.) in Serbia are presented. The species complex of 9 spider mite species and 16 phytoseiid species was recognized on 10 Prunus species. A total of 17 mite species were found on cherry plum (Prunus cerasifera Ehrh.) and blackthorn (Prunus spinosa L.), 16 species were found on sweet cherry (Prunus avium L.), and 13 species were found on plum (Prunus domestica L.). The highest coefficient of constancy among the spider mites was found for Bryobia rubrioculus (Scheuten) (27.9%), and among the phytoseiids for Euseius finlandicus (Oudemans) (58.7%). Very significant positive values of the association index were found for the pairs: Typhlodromus (Typhlodromus) pyri Scheuten–Bryobia angustisetis Jakobashvili, Neoseiulella aceri (Collyer)–Panonychus ulmi (Koch), N. aceri–Bryobia sp., Phytoseius corniger Wainstein–T.(T.) pyri, N. aceri–P. echinus, P. macropilis –Paraseiulus soleiger (Ribaga). Significant positive values were noted for the the pairs P. corniger–Bryobia sp., P. echinus–Bryobia sp., and K. aberrans–P. echinus. Very significant negative index values were detected for the pairs E. finlandicus–K. aberrans and E. finlandicus–P. macropilis, and a significant negative index of association for the pair A. andersoni–A. viennensis.

The paper presents the results of the study performed with aims to determine the presence and diversity of Phytophthora species on maple trees in Serbia. Due to high aggressiveness and their multicyclic nature, presence of these pathogens is posing significant threat to forestry and biodiversity. In total, 29 samples of water, soil and tissues were taken from 10 different localities, and six different maple hosts were tested. After the isolation tests, 17 samples from five different maple hosts were positive for the presence of Phytophthora spp., and 31 isolates were obtained. After the detailed morphological and physiological classification, four distinct groups of isolates were separated. DNA was extracted from selected representative isolates and molecular identification with sequencing of ITS region was performed. Used ITS4 and ITS6 primers successfully amplified the genomic DNA of chosen isolates and morphological identification of obtained isolates was confirmed after the sequencing. Four different Phytophthora species were detected, including P. cactorum, P. gonapodyides, P. plurivora and P. lacustris. The most common isolated species was homothallic, and with very variable and semipapillate sporangia, P. plurivora with 22 obtained isolates. This is the first report of P. plurivora and P. gonapodyides on A. campestre, P. plurivora and P. lacustris on Acer heldreichii and first report of P. lacustris on A. pseudoplatanus and A. tataricum in Serbia.

Picea omorika (Pančić) Purkyne is a well-known endemic conifer species. However, there have been few morpho-anatomical studies to date. Several years ago, preliminary population studies of P. omorika were published, but with the inclusion of additional populations, it became necessary to confirm whether the southernmost population from Mileševka Canyon, also known as var. vukomanii, (Pavlović and Matović 1994), remains distinct from the others. Two-year-old needles from the lower third of the crown were collected in late autumn from seven natural populations of P. omorika from Serbia and from the border with Bosnia and Herzegovina. The variability of ten morpho-anatomical traits and the cross-sectional anatomy of Serbian spruce needles were examined in seven natural populations in Serbia. Needle length was measured with a digital calliper, and the nine other needle traits, needle width, needle thickness, vascular bundle diameter, resin ducts diameter, number of resin ducts, distance between vascular bundle and resin duct, cuticle and epidermal thickness, hypodermal thickness, and hypodermal width, were examined under a light microscope. For most of the traits studied, the Štula population had the highest values, whereas the Bilo population had the lowest. Needles with triangular sections are most common in the southern part of Mt. Tara, while elliptical and rhomboidal sections are characteristic in populations at the edge of the distribution range in Serbia. Multivariate analyses separated populations into two main groups. Both principal component analysis and discriminant analysis indicated population overlap, while cluster analysis identified three main groups. Multivariate analysis of bioclimatic data and a correlation study of morpho-anatomical traits were also performed. Based on bioclimatic parameters, individuals in the populations from Mileševka and Štula showed the most distinct characteristics. Mantel and partial Mantel tests confirmed no correlation between the complete set of morphological traits and bioclimatic parameters, even after adjusting for regional differences.