The aim of this research was to determine the Cu, Ni, Zn, Cd, and Pb contents in the following wild plants: dandelion (Taraxacum officinale Web.), broad-leaved plantain (Plantago major L.), and ribwort plantain (Plantago lanceolata L.) collected from the natural environment at three different locations in the north of the Republic of Srpska, in the surroundings of Banja Luka (two localities) and Doboj (one locality). The examined species represent wild edible and medical plants, most commonly used in folk medicine. Plant material and associated soils were air-dried, acid digested, and analyzed by atomic absorption spectrometry (AAS). The results have shown the highest Zn contents in all examined plants, which were followed by the contents of other determined biogenic elements (Ni and Cu), while contents of toxic elements (Pb and Cd) were noticeably lower. The contents of potentially toxic elements determined in the plants were lower than recommended limits of toxicity, with the exception of the location L3-Stanari where elevated Ni contents were found in all examined plants and the associated soil. This implies an evident risk in case of consumption of the plants grown at this location and the need for further investigation in order to establish the exact degree of contamination and to implement proper activities.

U radu su predstavljeni višegodišnji rezultati istraživanja prisustva vrste Ambrosia artemisiifolia L. u korovskim zajednicama na teritoriji Republike Srpske. Snimanje korovske vegetacije vršeno je metodom Braun- Blanquet-a (1964). Ambrosia artemisiifolia L. je konstatovana u devet zajednica od kojih je najzastupljenija u asocijaciji Panico-Galinsogetum parviflorae Tüxen et Becker (1942). Posebno je značajno prisustvo u okopavinskim usjevima, strništu i višegodišnjim zasadima. U vinogradima Ambrosia artemisiifolia L. je prisutna u šest od ukupno devet zajednica gdje ima najveću pokrovnu vrijednost. Na sjevernom dijelu teritorije Republike Srpske izdvojen je facijes Panico-Galinsogetum ambrosiosum artemisiifoliae u kojem najveću brojnost i pokrovnost ima Ambrosia artemisiifolia L. Njeno masovno širenje je posljedica bioloških osobina, ulaska u agrofitocenoze, antropogenog uticaja i mnogo neobrađenih površina.

Taxonomy of Xanthium genus is very problematic because of numerous described taxa and low morphological distinction among species. In this study anatomical and genetic variability of Xanthium genus in the region of Bosnia and Herzegovina was analyzed. Based upon morphological characteristics analyzed plant material two species X. spinosum and X. orientale were determined. Within species X. orientale two infraspecific taxa X. orientale subsp. italicum and X. orientale subsp. riparium were identified. The anatomical differences were observed at the level of species, but they were not ascertained at subspecies level. The genetic results based on ITS2 sequences were in accordance with anatomical analyses. Regarding anatomical and genetic analysis two species were confirmed but there were no differences at the subspecies level.

Xanthium species are native to America, although it has been shown that reintroduction has occurred between the Old and the New World. Owing to the selective colonization of certain genotypes, these species are adapted to different habitats and have so far successfully colonized a vast number of habitats in many countries. Although Xanthium species can be used for medicinal purposes (extracts of X. strumarium have been used for cancer treatment, because they inhibit the development of cancer cells and are also used for treating inflammatory diseases), due to its toxicity (high amounts of carboxyatractyloside) and wide distribution in agricultural, ruderal and coastal areas, in most countries they are characterized as invasive weed species. These species invade many different crops, such as maize, wheat, soybean, potato, sunflower, tomatoes, tobacco, rape, orchards and vineyard, and can sometimes also be found in grain crops, when full tillering fails to occur. Nomenclature and identification of the plant material follows modern systematic principles according to Kiraly (2009) and the Plant List (2019). The distribution of the identified species is presented on UTM (Universal Transverse Mercator) maps. The distribution of the studied species was presented with the digital elevation model (Digital Elevation Model, DEM) of B&H with a resolution of 20x20 m in a 10x10 km grid. Quantitative representation of Xanthium species was done by a modified Braun Blanquet (1965) model. This work represents a detailed study of the distribution of Xanthium species in the territory of Bosnia and Herzegovina (B&H). In the study are, morphological determination has confirmed the presence of two species: X. spinosum and X. orientale. Within the species X. orientale, two subspecies were identified: X. orientale L. subsp. italicum (Moretti) Greuter and X. orientale L. subsp. riparium (Čelak.) Greuter.. Based on the results of the distribution and number of identified species, it can be concluded that in the studied area X. orientale subsp. italicum is a widespread weed species . Even though X. orientale subsp. riparium was found on only one location, due to the occurrence of cross-polination between subspecies, and even species, it can be said that the species X. orientale has an invasive character. Considering that the presence of X. spinosum was ascertained only in the southern parts of B&H, it can be characterized as a harmful weed species which is not in expansion.

The effectiveness of 12 pre-em herbicides in controlling ragweed was studied: atrazine, alachlor, acetochlor, alachlor+linuron, S-metolachlor, pendimethalin, metribuzin, prometryn, napropamide, imazethapyr, oxyfluorfen and dichlobenil. The research was conducted over two years, where the herbicides were applied in May on soil that had been prepared for sowing, but not sown. The efficacy was observed 30, 45 and 60 days after the application. Herbicides were used in 4 different doses: D1 which is ½ of the recommended dose, D2 is the lowest recommended dose, D3 is the highest recommended dose and D4 is the dose where the herbicides were used with the dose higher than it is recommended (D3×1,5). Efficacy is expressed as the percentage of efficacy for the number and fresh weed biomass, compared to the control. Coefficient of multiple correlation between the percentage of efficacy (PE), as a dependent variable, and the dose (D) and the number of days from the application of herbicides (DAA), as independent variables is statistically significant and in all cases it ranges between 0,853** and 0,961****. Partial correlation coefficient of efficacy percentage dependent on the herbicide dose is positive and in almost all cases highly significant, varying from 0,739** to 0,956****. Partial correlation coefficient between the herbicide efficacy percentage for common ragweed biomass and time after herbicide application is negative and statistically significant, or highly significant and varies between -0,606* and -0,904***. The partial correlation coefficient of the herbicide efficiency percentage for the common ragweed plant number and days after herbicide application, is also negative and varies, depending on the herbicide, between -0,182NZ and -0,923****.