Screening sticky traps under low magnification for adult Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood) and Aleyrodes spp. (Hemiptera: Sternorrhyncha: Aleyrodidae)

Whiteflies are commonly transported in international plant trade, accounting for 25% of arthropods found in association with imported plant material in England and Wales between 1996 and 2006. Several species are of quarantine significance and rapid, accurate identifications are essential in order for phytosanitary services to decide upon appropriate action. Whitefly taxonomy is based on the puparium, but these are often difficult to detect when present at low densities. Adults are more conspicuous and are readily caught on yellow sticky traps. Screening traps under low magnification for adult Bemisia tabaci , Trialeurodes vaporariorum and Aleyrodes spp. using pigmentation characters was evaluated; 5151 adults were examined on 238 traps and their identity predicted. Twenty-one percent of the adults were slide mounted and examined under high magnification to check their identity. The overall accuracy of the initial whitefly species prediction under low magnification was 98%. The speed and reliability of detecting adult B. tabaci on sticky traps was greatly improved and the number of adults requiring slide preparation reduced (by an average of 46% per trap) resulting in significant financial savings, compared to randomly selecting adults for slide mounting. Protocols are presented for removing adults from traps and making microscope-slide preparations.