Balloonvine (Cardiospermum halicacabum) was recently introduced in Paraná State, and it has caused economical damages in soybean crop in the Southern region of Brazil. In order to determine time and emergence rate, the competition and the survival of balloonvine with soybeans cultivar Embrapa 62, grown under two management systems, an experiment was carried out at Londrina, PR, from 1997 to 2000. Five population densities of ballonvine (zero, 60, 120, 240 and 480 seeds/m²) were established by sowing seeds in till and no-till managements for soybeans. A split-plot completely randomized block, with four replications, was used. An annual seedbank decrease rate of 61.6% and 56.4% was observed for till and no-till, respectively, related to six and seven years survival. Annual rates of emergence, in the absence of reinfestations, were higher in no-till (42.6%, 32.0% and 5.0%) than till (29.9%, 10.9% and 0.7%), in those three years. Losses of soybeans were estimated at an average of 8,1% in the presence of 10 plants/m² of balloonvine over 3,549 kg/ha of soybeans. Balloonvine presents significant infestation and competition hability in the soybean crop, and it tends to be eliminated by environmental conditions that favor downy mildio (Peronospora farinosa) attach.
seedbank; weed; biology
