Influence of Flight and Colour Morph on Susceptibility of Sitobion avenae to Infection by Erynia neoaphidis

The influence of clone and morph on the infection of Sitobion avenae with Erynia neoaphidis was examined in laboratory assays. The LC50-values were low; green alates: 0.8-1.8, green apterae: 2.9, brown alates: 1.5 and brown apterae: 2.6-3.6 conidia mm(-2). Within each of the two inoculation occasions, alates of both clones were significantly more susceptible than apterae, while there was no difference between the two clones. The LT50-values at 18degreesC varied between 6.4 and 7.5 days and there was no significant difference in LT50-values between either the two different coloured clones or between alates and apterae.