and has submarginal shed skins. The body of the adult female is yellow. The male 
cover is small and has submarginal shed skins. 
The elm armored scale overwinters as second instars on the bark of the host, and 
first instars appear in early May in Ohio (689). This species does not seriously 
damage its host. The only naturai enemy known Is a parasitic wasp. 
The Putnam scale, Diaspidiotus ancylus (Putnam), is probably native to North 
America and occurs throughout most of the United States. The species is poly- 
phagous but is commonly found on maple, basswood, and elm. The Putnam scale 
may be found in natural and ornamental vegetation. The adult female cover is 
circular, convex, gray or black, and has yellow or red subcentral shed skins. The 
body of newly matured adult females is yellow: on older females the anterior 
portion of the body is brown. The male cover is similar to that of the female but is 
oval and has subterminal shed skins. 
The Putnam scale has two generations per year in Maryland" and Illinois (//46) 
and one in Iowa (926) and Ohio (605). The species apparently overwinters as adult 
females on stems. In those areas where two generations occur, first instars appear 
early in the year and settle on leaves or stems; those that are on leaves are different 
morphologically from those on stems (//46). Adult females and winged males are 
present in early July. Eggs and first instars appear in July, and adult females and 
wingless males are present in late summer and fall. Putnam scale is reported to kill 
twigs and branches on heavily infested trees. Natural enemies include more than 
three chalcidoid wasps, a lady beetle, a gall midge, and two fungus species. 
Diaspidiotus liquidambaris (Kotinsky), the sweetgum scale, is native to North 
America and probably occurs in all areas where natural stands of sweetgum are 
found. This species 1s reported almost entirely on sweetgum and is found on natural 
and ornamental vegetation. This species forms a small gall-like structure on the - 
leaves of its host. The cover of the adult female on the leaf has a large, yellow, 
central shed skin with white wax around the margin. On stems the adult female 
scale is white or gray with subcentral shed skins. The body of the adult female is 
yellow. The male cover is oval, white, and has a yellow submarginal shed skin. 
The sweetgum scale has two generations per year in Maryland and overwinters as 
fertilized adult females on the bark (//72). In Maryland, eggs and first instars 
appear in mid-May and are present until the end of June. Settling occurs almost 
entirely on the leaves. Adults are first present in mid-June. First instars of the 
second generation appear in early July and are present until early October. Settling 
occurs on both the leaves and the stems. Adults of the second generation appear in 
early to mid-September. Adult males are winged in the first generation and wingless 
in the second. The sweetgum scale does not cause serious damage to its host. A 
chalcidoid wasp has been reared from this scale. 
Diaspidiotus osborni (Newell & Cockerell), the Osborn scale, is apparently 
indigenous to North America and is reported in nearly every eastern State. This 
scale is reported on several native tree genera but prefers oaks. The cover of the 
adult female is circular, flat, gray, and has yellow, subcentral shed skins. The body 
of the adult female and the eggs are yellow. The male cover is similar, but is smaller, 
oval, and has a submarginal shed skin. 
Osborn scale has two generations per year and overwinters as mated adult 
females on stems in Maryland (//72). Crawlers are present in Maryland in late May 
and June and again in August. Males of the first generation are winged; those of the 
'” Stoetzel, M. B. (personal communication). USDA ARS Syst. Entomol. Lab., Beltsville, Md. 
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