The whitefly Aleyrodes proletella L. (Hemiptera: Aleyrodidae) has become a major agricultural pest on a broad range of Brassica crops in Europe and has spread to North and South America and Australia. In order to understand its present outbreak, information about its life history parameters in relationship to different host plants is needed. Therefore, we tested the reproduction potential of A. proletella on four different host plants under greenhouse conditions: Kohlrabi, kale, white cabbage, and winter oilseed rape. The influence of host plant on preoviposition period, fecundity, survival rate, and sex ratio was examined. Additionally the effect of mating scenario (45-d mated females and males; virgin females and males; 6-d mated females) on life history parameters of A. proletella adults was evaluated. The mating scenario did not significantly influence the survival rate of A. proletella females and males and did not impact female fecundity and preoviposition period. Fecundity of A. proletella was significantly affected by host plant species: the shortest preoviposition period and highest oviposition rate was observed on winter oilseed rape, while the longest and lowest was recorded on white cabbage. The survival rate on white cabbage was significantly lower compared with those reared on the other host plants. The sex ratio of A. proletella progeny was also significantly affected by the host plant species. Our research indicates that winter oilseed rape is a highly suitable host for A. proletella in terms of fecundity, survival rate, and sex ratio, which might explain the current outbreak of A. proletella.