Cotton leaf curl disease, a viral infection vectored by the whitefly Bemisia tabaci (Gennadius), is a major threat to the cotton industry in India and Pakistan. We examined the settling preferences of B. tabaci adults on infected versus healthy cotton plants under choice conditions. For experiments with plants at 20 and 35 days post-inoculation (DPI), whiteflies preferentially settled on healthy cotton plants after 8 and 1 h of release, respectively. Whiteflies, however, were unable to discriminate between virus-infected and healthy cotton plants at 5 DPI. Our results suggest that whiteflies' preference for healthy plants compared with diseased plants can lead to rapid virus spread in the field, resulting in higher crop losses.
