White peach scale, Pseudaulacaspis pentagona (Targioni-Tozzwtt) (Homoptera: Diaspididae). Photo by J. V. Robinson.
Common Name: White peach scale
Scientific Name: Pseudaulacaspis pentagona (Targioni-Tozzwtt)
Order: Homoptera
Description: Full-grown male scale insects are white, about 1/32 inch long and elongate in shape. Adult males emerge as tiny two-winged insects. The female scale insect armor is irregular and roughly oval in shape, up to 1/16 inch in diameter and whitish with a yellowish or reddish spot. The female’s body is underneath the armor. Nymphs resemble adult scale insects but are smaller and female nymphs lack the spot.
Life Cycle: Intermediate adult females overwinter and produce a clutch of eggs underneath their scales in the spring. Six-legged nymphs, called crawlers, reported hatch from eggs in about 4 days, but observations in Texas suggest that it may take 30-60 days. Crawlers settle in about 2 days and begin develop through several stages (instars), the first lasting 7 to 8 days. Adult females develop from the second nymphal stage in about 12 days, and winged males develop through this stage for about 5 days before emerging as winged adults 7 or 8 days later. Development from egg to adult can occur within 35 to 40 days. Males seek female scale insects and mate. Mated females begin laying eggs after about 16 days. Three generations occur annually.
Habitat, Food Source(s), Damage: In addition to peach and plum trees, this species also infests catalpa, chinaberry, French mulberry, lilac, persimmon, privet and walnut. In severe cases, they appear as white, cottony masses encrusting the bark of the tree. These scale insects can also occur on leaves and fruit. Scale insect feeding activities can result in early leaf drop. Heavily infested trees can become stunted and parts or all of the tree can die.
Pest Status: Often observed causing trunks and lower branches of peach trees to appear to turn white because of a buildup of high numbers of scale insects; can affect tree health; medically harmless.
For additional information, contact your local Texas A&M AgriLife Extension Service agent or search for other state Extension offices.
Literature: Carter et al. 1980.