Esterase variation and squash induction in B-type Bemisia tabaci (Homoptera: Aleyrodidae)

Polyacrylamide gel electrophoresis was used to study esterase variation in a population of B-type Bemisia tabaci (Gennadius). A total of six esterases was identified within an overall B-type pattern. However, both qualitative and quantitative variation in some of these esterases gave three clearly defined phenotypes. One of these lacked esterase E 0.14 which until now has been the key band used to classify B-type strains electrophoretically. A strain homozygous for the E 0.14 null allele (B-Null) retained the ability to induce squash silverleaf, a plant physiological disorder which hitherto has only ever been associated with whitefly strains possessing this band.