or on closely related ones. The upper surfaces of infested 
leaves may be either whitened, or brownish, or dead in appear- 
ance. The undersurfaces are speckled with eggs, excrement, and 
cast skins of the developing nymphs. The leaves of heavily in- 
fested trees may turn entirely brown and fall off. The winter is 
spent as adults (under bark scales or other cover on the host 
tree), or as eggs (cemented te the undersurfaces of leaves or 
embedded in leaf tissues). Most species have two generations a 
year. 
The sycamore lace bug, Corythucha ciliata (Say), occurs 
throughout the Eastern United States (725) and in southern Can- 
ada. Its preferred host is sycamore, but it also feeds on ash, 
hickory, and mulberry occasionally. The adult (fig. 12) is white 
and about 3 mm. long. Overwintering adults emerge early in the 
spring and deposit their eggs along the ventral surface of the 
midrib of a leaf. Hatching occurs in 2 to 3 weeks, and the nymphs 
feed for 5 or 6 weeks. There are two generations per year in the 
North, probably more in the South. Light feeding causes a stip- 
pling of foliage. Heavily infested leaves of sycamore turn white and 
drop prematurely. During dry weather this may result in severe 
injury. 
COURTESY CONN. AGR. EXPT. STA. 
FIGURE 12.—Adults of the syca- 
more lace bug, Corythucha ciliata. 
The oak lace bug, Corythucha arcuata (Say), feeds on white, 
bur, and chestnut oaks from Alabama and the Carolinas to 
southern Canada. Connell and Beacher (156) discussed its life 
history and control. The winter is spent in either the egg or adult 
stage. Infested leaves appear grayish-white. Heavily infested 
trees may be defoliated, especially during dry weather. Bur oak 
in shelterbelt plantings is especially susceptible. 
The elm lace bug, Corythucha ulmi O. & D. feeds on American 
elm in many Eastern States and southern Canada, and on Si- 
berian elm on the Northern Great Plains. It is capable of defoli- 
ating its host. 
Heavy infestations of Corythucha mollicula O. & D. (=salicis 
O. & D.) (=canadensis Parsh.) may seriously injure willow, its 
only known host, throughout the Eastern States. Heavy infesta- 
tions of the hackberry lace bug, C. celtidis O. & D., often occur on 
hackberry in the Midwest. The species has also been reported 
from Florida. C. pallipes Parsh. (=betulae Drake=cyrta Parsh.) 
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