Dialeurodes chittendeni

The rhododendron whitefly can be a significant pest of its namesake host in the US. It was first reported in the United States in 1932 on rhododendrons from England; however, the insect may be native to parts of Asia. Reports from British Columbia indicate that rhododendrons brought from Kent, England in 1933 and 1934 were slightly infested with this insect. Adult females lay their elongate-oval, smooth eggs on the undersides of host plant leaves, attached with a short stalk. Nymphs hatch from these eggs and adhere themselves to the leaf underside, where they feed the entire time until adulthood. The immatures may look like and be confused for scale crawlers on the leaf undersides; they are semi-transparent, elliptical in shape, and become rounder as they mature. A single generation of the rhododendron whitefly may occur per year. The overwintering life stage is the immature nymph. Nymphal instars may overlap in their timing at a single location during the growing season, leading to variation. The final nymphal stage (immature) is sometimes referred to as a "pupae"; however these insects do not undergo complete metamorphosis. This final nymphal stage ("pupa") is transparent, white, and papery and 1.25 mm long. Stout spines are found along the edges of the "pupa" and tiny legs and mouthparts may be examined with magnification. Adults are present from mid-May to early August and are dusty-colored (white wings that are 8 mm across and a yellow body). Adults are said to be extremely active during sunny weather (Olds, 1935). When disturbed, the adults may fly around the infested shrub and then quickly settle back on the undersides of the leaves. Adults may be capable of short-range independent movement, however longer distance dispersal is likely human-aided.