Parasitoid's performance is subject to parasitism decisions influenced by host quality and parasitoid's age. We evaluated parasitism, emergence, and the progeny sex ratio proportions of Telenomus podisi (Ashmead), Trissolcus urichi (Crawford), and Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) females of different age attacking Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae), an important soybean pest. Eggs were offered to females of T. podisi 1–10 d old, T. urichi 1, 3, 4, or 6 d old, or T. basalis 1–6 or 8 d old. Average egg parasitism proportions were 0.71 and 0.79 to T. podisi and T. urichi, respectively; and preimaginal survivorship was>97% for both species. Trissolcus basalis females 1, 2, and 3 d old did not parasitize P. guildinii eggs, and high parasitism proportions were recorded from older females, but only 0.5 of females attacked host eggs. A greater proportion of males were produced in the progeny of T. podisi and T. urichi as maternal age increased, but no differences were found in the progeny of T. basalis wasps of different ages. The results from this study indicate that performance of T. podisi and T. urichi would not be affected by the age of the females. However, aging would induce T. basalis females to attack P. guildinii, although it is known that their main host is Nezara viridula (L.) (Hemiptera: Pentatomidae). Under certain circumstances, such as shortage of preferred host availability, high egg load, and short life expectancy, this wasp may include P. guildinii as a host.