Helianthus tuberosus (L.) is a perennial broadleaf plant, native to North America. In the years 2010 and 2011 were conducted a surveys to detected the occurrence and distribution of Jerusalem Artichoke ( Helianthus tuberosus L.) in Prievidza District and Piešťany District. In Prievidza District was monitored the localities among the riverbanks (47.15 km) of Nitra River and Handlovka River. Five localities in Prievidza District were chosen, where occurrence and population density of Helianthus tuberosus (L.) in the years 2010, 2011 were determined. In Piešťany District were chosen three localities, where occurrence and population density of Helianthus tuberosus (L.) in the year 2011 were determined. Survey in the localities was conducted at two terms: Summer time: June - August 2010, 2011 and autumn time: September – November 2010, 2011. On the trial localities the amount of Helianthus tuberosus (L.) per m 2 was detected. An actual infestation of ecosystems with H. tuberosus was evaluated by count method per m 2 . Screening of trial localities was made on the quadrant of 1m 2 areas with four replications. One quadrant of each replication was (1.0m x 1.0m). Minimum three randomly established sample quadrants were detected. Jerusalem artichoke ( Helianthus tuberosus (L.)) was found mainly on the riverbanks in dense populations. The lower densities of H. tuberosus were detected on the ruderal areas and near railway. Jerusalem artichoke ( Helianthus tuberosus L.) is frequently found in moist habitats such as river and stream banks, meadows and waste areas, as well as in cultivated fields. Helianthus tuberosus (L.) is not only noxious invasive plants with high potential to become weed in agricultural landscape. This plant is also medicinal plant, with high nutritional quality and with its high biomass production has potential to become a source for production of ethanol for biofuel. The originality of this paper is in monitoring of an invasive plant species Jerusalem Artichoke ( Helianthus tuberosus L.) in the southwestern part of Slovak Republic and its distribution in natural ecosystems.

Helianthus tuberosus (L.), occurrence, river bank

Presentation: oral