After the 2013 blueberry harvest, we received blueberry foliage samples collected from blueberries in Bacon County, Georgia. The undersides of the leaves were infested with large numbers of whitefly pupae that were identified as Tetraleurodes ursorum Cockerell (Aleyrodidae: Hemiptera). This species is sometimes called “bearberry whitefly” because it was first reported on the common bearberry (Arctostaphylos uva-ursi) on Flagstaff Mountain in Boulder, Colorado. Bearberry whitefly pupae are oval, shiny black, about 0.7 mm (0.03 inch) long and 0.5 mm (0.02 inch) broad with a little white secretion around the base but no distinct fringe, and no dorsal secretion. Adults are about 1 mm (0.04 inch) long. The body from the above is blackish and covered with white mealy wax. The base and sides of the abdomen are white, the extreme base of wings yellow, and lower surface of the abdomen is light yellow with the last two segments gray. The eyes are black and completely divided, and the wings are white.

Whiteflies are related to scale and have a complex lifecycle. Eggs hatch to a mobile first instar, commonly known as crawlers. Once crawlers find a suitable location to feed and settle, they mature through a few stationary nymphal stages that feed to a final non-feeding nymphal instar, often called a pupa. The term pupa is a misnomer, a loose use of entomological nomenclature, because whiteflies do not truly develop through complete metamorphosis. Bearberry whiteflies colonize the underside of the blueberry leaves; the adults and eggs are commonly found on the lower surface of younger leaves whereas nymphal stages on somewhat older and mature leaves. Whiteflies have piercing-sucking (needle-like) mouthparts. They feed by inserting mouthparts into plant tissue and sucking the flowing sap or phloem. While feeding, they excrete a sweet, sticky liquid referred to as “honeydew”. Sometimes, they reach such high populations that cover the lower surface of the leaves with nymphs, pupae, and their associated honeydew. The honeydew excreted by nymphs can collect dust, lead to growth of sooty mold, and attract ants. Bearberry whiteflies are primarily postharvest feeder and do not seem to cause economic damage in blueberries.

BEARBERRY WHITEFLY PICS

Posted in: