ABSTRACT
Ambrosia artemisiifolia is known as one of the most dangerous aeroallergen yielding plants. It is also a very obnoxious weed in the agricultural fields. Ambrosia is a weed belonging to Asteraceae same as Parthenium. The plant can develop into a real nuisance as a pioneer plant in disturbed soils. The plants flower in late summer, in August and September. There are many species of Ambrosia, but the commonest and wide spread species of Ambrosia are Ambrosia artemisiifolia which is the dwarf species of ragweed and Ambrosia trifida commonly known as the giant ragweed. On account of highly allergenic properties of Ambrosia pollen, its aerobiology has been studied extensively in different European countries. A pollination calendar shows that the pollination period of Ambrosia in Austria is from mid-August to end of September with a peak in early September.
