RESUMO
The suitability of Macrosiphum euphorbiae (Thomas), Aulacorthum solani (Kaltenbach) and Acyrthosiphon kondoi Shinji (Hemiptera: Aphididae) as hosts for the aphid parasitoid Aphidius ervi Haliday was evaluated by assessing host size, host preference, and host quality. Tests were carried out in an environmental chamber at 22 ± 1ºC, 70 ± 10 percent RH and 12h photophase. Replicates (11) consisted of one 24h-old mated female of A. ervi without a previous oviposition experience. Female was released into a Petri dish (5 cm) with 20 2nd and 3rd instars of one of each aphid species tested on a leaf disc of the host plant onto a 1 percent water-agar layer. Parasitoid emergency was lower in A. kondoi (78.7 percent) compared to M. euphorbiae (92.2 percent) and A. solani (91.7 percent). Acyrthosiphon kondoi (0.36 mm) was the smallest host. The parasitoid showed preference (74.0 percent parasitism) for M. euphorbiae, the largest host (hind tibia length = 0.73 mm), which in turn yielded larger A. ervi females (0.75 mm).