Pennsylvania (//64) and three in Maryland (280). First instars and eggs of white 
peach scale are present in early to mid-May, early to mid-July, and late August to 
early September. The life history of white prunicola scale is advanced compared 
with that of white peach scale. First instars and eggs are present in late April to 
early May, late June to early July, and mid to late August. Males are necessary for 
reproduction in at least some populations. These species are very serious pests of 
peaches and ornamental cherries. On some hosts they may build to such heavy 
infestations that entire branches are white. Natural enemies include parasitic wasps, 
lady beetles, a thrips, a mite, and a green lacewing. 
Another species of Pseudaulacaspis that might be found in eastern forests is P. 
cockerelli (Cooley), which 1s polyphagous and occurs in Alabama, Florida, 
Georgia, Louisiana, and South Carolina. 
The Forbes scale, Quadraspidiotus forbesi (Johnson), 1s apparently native to 
North America and occurs throughout the United States. It is polyphagous and is 
often found on hickory, dogwood, apple, and Prunus spp. This species occurs in 
ornamental and natural vegetation. The cover of the adult female is circular or oval, 
flat or convex, gray, and has orange, subcentral shed skins. The body of the newly 
molted adult female is reddish yellow but becomes darker with age. The male cover 
is smaller and more slender than the female cover. The adult male may be reddish 
brown or yellow, and has wings. 
Forbes scale has two generations per year in North Carolina (/2/4) and Ohio 
(643), and overwinters as mated adult females. In North Carolina adult females 
give birth to first instars. First instars are present from June to early July and again 
in August. Wingless males have been reported in mid-April in Ohio (689). The 
species feeds on the stems and fruit of its host and can be a serious orchard pest in 
cherries, apples, and peaches in Michigan, Ohio, Illinois, Indiana, and North 
Carolina. Natural enemies include at least six hymenopterous parasites, several 
lady beetles, a mite, and two fung!. 
Quadraspidiotus gigas (Thiem & Gerneck), the willow scale, is apparently 
introduced into North America and occurs in New York, Ohio, Pennsylvania, 
Rhode Island, and Wisconsin in the Eastern States. Hosts are willow and poplar. 
The willow scale may be found in ornamental or natural vegetation. The cover of 
the adult female is circular, convex, gray, and has orangish-yellow subcentral shed 
skins. The body of the adult female is yellow. The male cover is similar to that of 
the adult female but is smaller, more elongate, and has a subterminal shed skin. 
The willow scale has one generation per year in Czechoslovakia (72/) and 
Germany (/066) and overwinters as second instar males and females. First instars 
are sometimes present in the winter but are killed before spring. In spring the adults 
are present and egg laying occurs from June to September. Males are necessary for 
reproduction in at least some populations. First instars are present from June into 
winter. Feeding takes place on the bark of the host; this species encrusts the bark in 
severe infestations. Damage may include deformation of the bark, death of 
branches, or even whole trees. Natural enemies include approximately 15 species of 
parasitic wasps and 4 species of lady beetles. 
The walnut scale, Q. juglansregiae (Comstock), is apparently native to North 
America and has a general distribution in the United States. This species is 
polyphagous and has been found on English walnut, holly, ash, elm, hickory, 
basswood, maple, sweetgum, yellow-poplar, among others. This scale occurs in 
natural and ornamental habitats. The cover of the adult female is circular, convex, 
grayish, and has reddish-brown subcentral shed skins. The body of the adult female 
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