Aphid bioassays

To evaluate the survival rates of R. padi, 20 apterous adults were transferred to the middle of the forth leaves and enclosed in clip cages (3 cm diameter), and after 24 h, the adult aphids were brushed off and 20 neonates were left in the clip cages to evaluate every day in the next 5 days (20 replicated maize plants for each group) (Carena and Glogoza, 2004; Mao and Zeng, 2014). To determine days from birth to first reproduction, life span, and progeny per aphid, one new neonate was placed on the middle of the forth leaf of each plant and the performance parameters were estimated until its death (20 replicated maize plants for each group) (Kettles et al., 2013).