resistance characterization of different oilseed cultivars of brassica to mustard aphid, lipaphis erysimi (hem.: aphididae) under greenhouse conditions

the mustard aphid, lipaphis erysimi kalt, is one of the most severe pests of brassica species in iran and other tropical regions in the world. seven cultivars of three brassica species including b. napus (cv. licord, elite, okapi, hyola 401, and rgs003), b. juncea (cv. land race) and b. rapa (cv. park land) were evaluated to study the antixenosis and antibiosis resistance to l. erysimi under greenhouse conditions at 25±2 °c, 60±5% rh, and a photoperiod of 16:8 (l: d) h). results of antixenosis test demonstrated that density of l. erysimi at different counting hours (48 and 72 h) was significantly different on examined cultivars (p < 0.05 and p < 0.01 after 48 and 72 h, respectively). aphid density on elite, okapi, and rgs003 cultivars was significantly higher than that on the other cultivars. in antibiosis test, the results showed that there was a significant difference in aphid life-table fertility’ parameters, with the exception of population doubling time (dt), between different cultivars (intrinsic rate of increase (rm): p < 0.05; net reproductive rate (ro): p < 0.05; mean generation time (t): p = 0.05 and finite rate of increases (): p < 0.05). the highest aphid rm was found on land race cultivar (0.324 female/female/day), whereas the lowest aphid rm was recorded on elite (0.278 female/female/day). our results suggest that elite, okapi, and rgs003 cultivars were the most resistant hosts for l. erysimi compared to the other tested cultivars. resistant cultivars identified in this study could be used for management control of mustard aphid.