Acylsugars, the primary components of the exudate secreted by type IV trichomes of Lycopersicon pennellii (Corr.) D'Arcy LA716, mediate the resistance of this accession to silverleaf whitefly, Bemisia argentifolii Bellows & Perring, n. sp. Reduction in the settling of the adult silverleaf whiteflies correlates with the concomitant increase in applied acylsugars. Oviposition of B. argentifolii is also affected by acylsugars, resulting in a reduction in the number of eggs and nymphs found; however, acylsugars do not affect hatching of nymphs. The threshold amount of acylsugars required for deterring settling and oviposition is under the amount of acylsugars (50 to 70 μg·cm–1) required for control of other insects.