THE SWEET-POTATO OR SILVERLEAF WHITEFLIES - BIOTYPES OF BEMISIA-TABACI OR A SPECIES COMPLEX

The recent emergence of whitefly species of the genus Bemisia as virus vectors and pests worldwide has stimulated investigations into their biology. The invasion of pantropical agroecosystems by an exotic white fly and increased pressures by indigenous whiteflies elsewhere have le d to the examination of Bemisia tabaci biology with a new perspective. The concept of host races or biotypes was proposed in the 1950s to de scribe select B. tabaci populations with definitive host associations and specific virus-vector capabilities. However, little attention has been given to the mechanisms involved. Biochemical, molecular, and who le-system approaches are underway to examine the underlying diversity among reproductively isolated populations or biotypes of B. tabaci.