STUDIES REGARDING THE DENSITY DYNAMICS OF AVENA FATUA WEED SPECIES ON WHEAT CULTIVATED IN MONOCULTURE (2 AND 3 YEARS) AND IN THE WHEAT–RAPE CROP ROTATION ON BURNAS PLATFORM (ALEXANDRIA)

Until 1995, the Avena fatua (odos) wasn’t even known as a weed in Burnas Plain wheat crop. Starting with the beginning of the first decade of the millennium, also fostered by the climate change process, Avena fatua has been slowly, but surely, installed in the area. By 2010 it reached almost 50 plants/m2 on wheat after wheat and about 90 plants/m2 in 3 years wheat monoculture. Over the past three years, the specie’s density has logarithmically increased up to 600 plants/m2 on wheat after wheat and to almost 900 plants/m2 in 3 years wheat monoculture. The surfaces identified by us have exceeded 1500 ha, while the yield losses reach up to 100%. In these conditions, the rape-wheat simple crop rotation reduces weed infestation and keeps it slightly variable between 5-10 plants/m2, well below the economic threshold of tolerance. At the same time, substantive amendments in weed’s biology and ecology were observed, it becoming therophytes - hemitherophytes due to climate change. Can talk about a weed infestation of the crop with biannual and annual forms. Between all the chemical methods used so far, very good results were obtained with the Pallas 75 WG product, at a dose of 150 g/ha, even without safener.