Plantas infestantes hospedeiras de Rhopalosiphum rufiabdominalis (Sasaki) (Hemiptera: Aphididae) em áreas de cultivo de arroz irrigado

rhopalosiphum rufiabdominalis (sasaki) is an insect of world-wide distribution that damages irrigated rice. from september, 2004 to february, 2005, nymphs and adults of this aphid were collected in several host weeds of rice farms in alegrete, quaraí and uruguaiana, located in western of state of rio grande do sul, and restinga seca, in central region of this state, brazil. the insect was found in the root of andropogon bicornis (west indian foxtail), echinochloa colona (jungle rice), oryza sativa (volunteer rice and red-rice), paspalum sp. (paspalum) and soliva pterosperma (lawn burweed).