Trophic enzymes of sweetpotato whiteflies, Bemisia tabaci (Gennadius) were studied in the putative A and B strains (cotton and poinsettia). Pectinases, cellulose and -amylase were found in both "strains." Neither proteinase (casein as a substrate) nor trypsin-like enzyme (BAPNA as substrate) were found in the SPW'S. -Galactosidase was found in SPW that had fed on cucurbits but not on those fed on cotton. A possible interpretation of this pattern of enzyme occurrence is that cellular materials are ingested by SPW, and that they are not limited to ingestion of phloem.