The San Jose scale may have as many as five generations per year, depending on 
the location. The overwintering stage in northern areas is predominantly settled first 
instars; in warmer areas all stages may be present, although first instars and gravid 
adult females seem to be most common. Parts of some generations are reported to 
aestivate during the first instar. It is not surprising that chemical control of this scale 
is difficult if one realizes that a single female may produce up to 400 eggs, and 
some of the resultant crawlers may develop rapidly while others go through a 
resting stage. After one or two generations there is little or no synchrony in first 
instar emergence, and nearly all stages are present at any one time (468). First 
instars are laid directly on the host, and males are common. This species is most 
frequently found on stems, twigs, and fruit, but it also may be collected on leaves. 
The San José scale is perhaps the most destructive scale insect in the United States. 
If left unchecked it is capable of building up to very large populations and may kill 
entire trees. It is a very destructive pest of shade, ornamental, and fruit trees. 
Natural enemies include a large number of parasitic wasps, lady beetles, nitidulids, 
and fungi. 
Other species of Quadraspidiotus that might be found in eastern forests are Q. 
socialis (Hoke) on oak from Georgia and Mississippi; Q. taxodii Ferris on bald- 
cypress from the District of Columbia, Florida, Georgia, Louisiana, Maryland, and 
Pennsylvania; and Q. tillandsiae Takagi & Tippins on Spanish moss from Georgia. 
Quernaspis insularis Howell, the island oak scale, and Q. quercicola Tippins & 
Beshear, the false oak scale, are native to North America. The latter is known only 
from Georgia, whereas the former is recorded from Arkansas, Florida, Georgia, 
and Texas. Until recently these species were considered to be the same as Q. 
quercus (Comstock), the western oak scale (//55), which apparently occurs only 
in the Western States. Because of the confusion, the precise distribution of each 
species remains unclear. It 1s likely that the island oak scale and false oak scale will 
be found in the Eastern States only, from Ohio to Florida and as far west as Texas. 
These scales are reported only on species of oak and are found primarily in natural 
situations. The cover of the adult female is oystershell-shaped, gray or white, and 
has terminal shed skins. The male cover is elongate, white, with a terminal shed 
skin. The male cover of the island oak scale has a conspicuous longitudinal ridge, 
whereas the false oak scale lacks this ridge. 
The life histories of the eastern species of Quernaspis are unknown, but the 
western oak scale overwinters in California as adult females or second instars 
(1028). In all three species the adult female occurs on the stems and twigs of the 
host, whereas the second instar male covers are found on the leaves. A single 
parasitic wasp 1s known on the western oak scale; natural enemies of the other two 
species have not been reported. 
The euonymus scale, Unaspis euonymi (Comstock), is probably native to the 
Old World and will undoubtedly be found wherever euonymus is grown. Although 
it is normally found on euonymus, it is also reported on 30 other genera of hosts 
including bittersweet, holly, and pachysandra (485). This species normally is found 
in ornamental plantings but occasionally is present in natural situations. The cover 
of the adult female is oystershell-shaped, convex, dark brown, and has yellow or 
brown terminal shed skins. The body of the adult female and the eggs are normally 
yellow or yellow-red. The male cover is elongate, white, has three longitudinal 
ridges, and a yellow terminal shed skin. The male is pale orange and winged. 
The euonymus scale may have two or three generations per year, depending on 
the locality. The primary overwintering stage is the mated adult female, although 
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