Host selection, development, survival, and reproduction of turnip aphid (Homoptera : Aphididae) on green and red cabbage varieties

Host selection, development, survival, and reproduction of the turnip aphid , Lipaphis erysimi (Kaltenbach), on selected green and red cabbage varietie s, Brassicae oleracea L. variety capitata, were studied in the laboratory. Although numbers of alate L. erysimi on different varieties varied generall y, more alate adults and nymphs were olsen ed on green than on red varietie s on day 3; whereas, these differences were not so significant on day 15. T here were no significant differences in slate adults on all sis varieties o n day 15. Numbers of nymphs and apterous adults of L. erysimi varied among the varieties. When mean numbers of those aphids on green varieties were co mpared with those on red varieties, the green varieties had more nymphs and apterous adults than those on the red varieties. Developmental durations o f L. erysimi nymphs also varied among all varieties, and the nymphs fed on green varieties developed longer than those fed on red varieties. Adult lon gevities on these cabbage varieties were not significantly different: where as, the adult fecundities were. Survival rates of L. erysimi varied greatly among all varieties, but there are no significant differences between the green and red varieties. Factors that might affect aphid host selection, gr owth, longevity, fecundity, and survivorship were discussed.