The effects of doses of the herbicide bentazon applied at post-emergence in the control of dycotiledonous weeds in onion crops were studied on a alluvial eutrophic soil with a clay silt texture. and 2.75%% of organic matter. The experiment was set according to a complete randomized design in a factorial arrangement of 2 x 5 x 2- 4 (two onion varieties: 'Bala Periforme' and 'Texas Grano': five herbicide application dates: 10. 20. 30, 40 and 50 days after emergence of the weeds: bentazon doses were 0,46g a.i./ha and 0.96 g a.i./ha: and four more tre atments: 'Baia Periforme' and 'Texas Grano' hoed and unhoed. The main types of weeds found were Galinsoga parviflora Cav.. Bidens pilosa L.. Euphorbia prunifolia Jacq., Brassica campestris L., Physalis angulata L.. Cassia tora L.. Emilia sonchifolia (L.) DC and Lepidium virginicum L Bentazon at the two used levels was efficient in controlling the competing weeds up to 60 days after the onion seedlings were transfered to the field. Non toxic effects of bentazon on the two onion varieties were noticed in the present trial.
Onion; bentazon; cultivais