Euphorbia dentata Michaux is an annual species which grows during spring and summer. Its has been recently introduced in the Province of Buenos Aires. In Azul district, during the last few years it has become an important weed with increasing propagation occuping a high proportio of agricultural land associated mainly with soybean, corn and sunflower crops. At present the limited available knowledge about this species makes difficult a rational and efficient management. Field studies to determine the propagation in the district of Azul, were conducted during three years. To check its propagation, enquiries to farmers were made. Also, all over the district, a transect across the agricultural land was conducted to survey several biological characteristics. The presence, density, emergence, germination, fruit and seed number per plant and dry weight were determined. Seeds have high viability. Its was demonstrated that the species occupies na area of approximately 250.000 ha that represent 40% of the district and 85% of the cultivated land, with levels of infestation from 20 to 200 plants per square metre. Under natural condition the weed shows two peaks of emergence and flowering is induced by day lenght. The species is described in detail and illustrated.
Euphorbia dentata; biology; botanical description