Bionomics of the proconiine sharpshooter Oncometopia tucumana Schröder (Hemiptera: Cicadellidae) from northern Argentina is reported. Leafhoppers were monitored during the entire season in a citrus orchard in Horco Molle, Tucumán Province, and also sampled in Jujuy and Salta Provinces. The sharpshooters were found from spring to late fall; they overwinter as adults and females do not lay eggs from Apr to Oct. Oncometopia tucumana is polyphagous, 12 plants in 11 families were recorded as its hosts for the first time. Egg masses of O. tucumana were attacked by 3 parasitoid species, Gonatocerus annulicornis (Ogloblin), G. metanotalis (Ogloblin), and G. tuberculifemur (Ogloblin) (Hymenoptera: Mymaridae), that collectively produced egg mortality close to 60%. Gonatocerus annulicornis was the main egg parasitoid, emerging from nearly 80% of the parasitized eggs.