Dialeurodes citri is a potential risk to glasshouse Citrus crops as well as ornamental trees and shrubs. Ecologically, whitefly are the tropical equivalent of aphids; opportunist insects with transient populations (Mound & Halsey, 1978). As poor fliers, it is believed that they have only moved from tropical environments with man's assistance. Continued statutory action taken against D. citri in the UK could be justified if it protected Citrus in southern EU MS. However, given that the pest occurs in the Citrus growing regions of the EU where it is not under official control, the PHSI are justified in focussing efforts against other pests that are not so widespread