Due to competition for water, light and nutrients the weeds are serious problems for certain kind of crops. They are responsible for the reduction in production. The survey and the recognition of different weeds and the their biological study permit a more efficient and economical way of control. The botanical material was collected in lowland crops during three different periods of the year. The purpose was to collect as many different species of weeds as possible. The phenology, the mode of reproduction, the frequency and cycle of weed species are important factors for the rational and effective control. Although the greatest amount of weed species collected belong to the Compositae and Gramineae, the most economically important species belong to the following families: Cyperaceae, Lythraceae, Onagraceae, Polygonaceae, Pontederiaceae and Portulacaceae.
Lowland; weed; survey; biolology