Does leaf pubescence of wheat affect host selection and life table parameters of Sipha maydis (Hemiptera: Aphididae)?

The influence of leaf pubescence of three wheat cultivars (Pishtaz, Ghuds and Falat) on preference and biological parameters of Sipha maydis (Passerini) was investigated under greenhouse conditions (25 ± 2 °C, 70 ± 10% RH and 14: 10 h (L: D) photoperiod). The results showed that Pishtaz had a greater density of trichomes compared to the other cultivars. In the preference test with whole plant, the number of aphids on Pishtaz was significantly greater than that on other cultivars at 48 hrs after infestation. Similarly, in the preference test on leaves, the numbers of attracted aphids per leaf was highest on Pishtaz. In the life table study, there was no significant difference of intrinsic rate of natural increase (rm) among the three studied cultivars but it was highest on Pishtaz (0.187 /day). Aphids’ net reproductive rate, doubling time, mean generation time and finite rate of increase did not show significant differences between the tested cultivars. According to our results, leaf surface pubescence of wheat is not an effective resistance mechanism against S. maydis.