Figure 5. Comparison of the height and breadth of the ecdysteroid peak in silverleaf whiteflies 4th instars and pharate adults reared on five host plants. Whiteflies were staged and collected, extracts prepared and ecdysteroid concentrations determined by EIA as described in Materials and Methods. Each value represents the mean of at least five separate determinations and is expressed in femtograms 20-hydroxyecdysone equivalents/10 µg wet weight. To avoid confusion, S.E. bars have not been drawn. Stage designations in white are for nymphs reared on greenbean and tomato plants (pubescent-leafed); stage designations in yellow are for nymphs reared on cotton, sweet potato and collard plants (glabrous-leafed).