Plants that are severely affected show yellowing on their leaves and are damaged by the sugary excretions of the insect. Similar to aphids, whiteflies excrete sticky honeydew which drips onto the leaves and fruit below. This shiny coat can, on the one hand, induce the growth of sooty moulds, which soil the fruit (additional rinsing necessary), and the affected leaves lose their assimilation surface, weakening the plants, on the other.
Bemisia tabaci was known as a farm crop pest in tropical and subtropical countries, affecting crops such as manioc, cotton, sweet potato, tobacco and tomatoes, until recently. However, its range of hosts encompasses more than 900 host plants from over 60 families (such as Asteraceae, Brassicaceae, Cucurbitaceae, Convolvulaceae, Euphorbiaceae, Fabaceae, Malvaceae, Solanaceae, etc.).
The development of the extraordinarily polyphagous subtype B made Bemisia tabaci a notorious greenhouse pest, infesting peppers, courgettes, cucumbers, lettuces and tomatoes, as well as hibiscus, gerbera, gloxinia and poinsettia (Euphorbia pulcherrima) in many parts of the world. It is quite likely that international trade with poinsettia plants is the largest propagator of this pest.