The effect of systemic organofosforate nematicide Terbufos (Counter 50G) application, on sugarcane (Saccharum sp.) in soil naturally infested with three ectoparasitic nematode populations Helicotylenchus dihystera, Criconemella ornata and Paratrichodorus sp. were evaluated in field microplots. Five sugarcane varieties (SP70-1143, RB813804, SP78-4764, CB45-3 and SP79-1011), two rates of nematicide application 60, and 80 kg of commercial product per hectare (c.p./ha) applied at planting, together with control plots, were arranged factorially with five replications in a complete randomized block design. Evaluations were based upon nematode population densities and reproductive factors (RF = Pf/Pi) of genotype x nematicide combinations in treated and non treated plots. Sixteen months after planting there were no significant differences in population densities at the nematicide rates considered, except for the C. ornata x Terbufos (80 kg/ha) combination, in the SP70-1143 variety. Due to the low RF, probably associated with a long dry season during the experiment, it was not possible to determine genotype fitness in relation to three nematodes.
