The nymphs remain fixed to the plant and feed for about four weeks. After a pupa stage, the adults emerge and live for about one month. Within a population, all life stages are present, and generations often overlap. Damage Whiteflies damage plants by sucking out plant juices. Because large amounts of sap can be removed, primarily by the developing nymphs, heavily infested plants can be seriously weakened and grow poorly.
Whiteflies suck out plant juices.
This seriously weakens the plant. Also, because whiteflies suck out more plant juice than they can digest, the excess is excreted as a sweet, sticky substance called honeydew. The honeydew covers leaf surfaces and acts as a growth medium for a black, sooty mold. Both the removal of plant juices and the presence of the black, sooty mold growing on the honeydew can interfere with photosynthesis. In some parts of the country, some species of whitefly can transmit several plant viruses.