INFLUENCE OF UPLAND RICE MECHANIZATION ON THE INFESTATION AND DAMAGE OF RHOPALOSIPHUM-RUFIABDOMINALE (SASAKI, 1899) (HOMOPTERA, APHIDIDAE)

The root aphid Rhopalosiphum rufiabdominale (Sasaki, 1899) infestation and damage were studied in an experiment of upland rice mechanization using the cultivar Caiapo. The five sowing machines and the two soil preparations used showed significant differences in the percentage of infested plants and plant population. The Caiapo grain yield was estim ated to have been reduced by the aphid in about 28.5%, being 15.2% ass ociated to missing plants and 13.3% to the feebleness of the remaining plants. To reduce the insect damage, the first step is to choose an a dequate sowing machine, followed by a correct soil preparation and tre atment when the crop infestation shows, at the beginning of tillering and reproductive phases, respectively, 13% and 5% of the plants with a phid colonies on the roots.