In the years 2000 - 2009 (10 years) was conducted weed survey on the farms in conventional farming system. The aim was to detected top 10 of the most harmful weeds, as important biotic stress factor, on the farms in the canopies of winter wheat in all production regions of the Slovak Republic. The actual weed infestation was evaluated by standard methods common used by a counting method per square. The four randomly established sample quadrants were situated minimally 20 m from field margin and apart each other, respectively. Three most dangerous weeds in winter wheat stands in the maize production regions were: Anthemis spp., Tripleurospermum perforatum (Mérat) M. Lainz and Cirsium arvense (L.) Scop.. In sugar beet production region it was Galium aparine L., Stellaria media (L.) Vill. and Anthemis spp. and in potato production region it was the same as in maize production region Anthemis spp., Tripleurospermum perforatum (Mérat) M. Lainz and Cirsium arvense (L.) Scop.. Temporal dynamic of actual weed infestation depends on production region. In the last decade was detected the very significant increase of Cirsium arvense (L.) Scop., Galium aparine L. and Apera spica venti (L.) P. Beauv. in sugar beet production region and volunteer winter oilseed rape in potato production region. Significant increase was detected by Cirsium arvense (L.) Scop. and volunteer sunflower in maize production regio; Anthemis spp., Avena fatua L., volunteer winter oilseed rape and Tripleurospermum perforatum (Mérat) M. Lainz in sugar beet production region. Very significant decrease of Apera spica venti (L.) P. Beauv. was detected in potato production region and population of Avena fatua L. significant decrease in maize production region. After herbicides control the significant changes in weed flora were noted in term of abundance and share of some weed species on total weed community The originality of result is in mapping the weed species in cultural crops.

temporal dynamics, weed infestation, winter wheat, Slovak Republic

Presentation: oral