26 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 



Fig. 19. — European elm scale: an infestation on an elm twig in spring. 

 Each scale has a reddish center and a white fringe. 



where they settle and feed until late summer. Many migrate 

 back to a limb or branch to hibernate, but some are lost when 

 the leaves drop in autumn. 



Control Measure 5 (end of circular) in late winter or Con- 

 trol Measure 3 in June. 



Scurfy Scale, Chionaspis furfura (Fitch), fig. 20. — Widely 

 distributed and a pest of fruit and shade trees in addition to elm, 

 the dirty white, pear-shaped scale of this species is about one- 

 eighth inch long. Infestations of this scale are more conspicuous 

 than the infestations of some other scales, especially when they 

 are dense enough to give the infested bark an ugly appearance. 

 Withdrawal of sap from a tree by an infestation of this scale 

 reduces the vitality of the tree, kills branches and limbs, and 

 sometimes, if the tree is young, deforms it. 



The purple eggs, which carry the insect through the winter, 

 begin hatching toward the last of May, giving rise to tiny purple 

 crawlers that move away from the mother's shell. The crawlers 

 soon settle on the bark to feed and to make shells of their own. 

 The scale covering of the female is broad, while that of the male 

 is narrow and has three longitudinal ridges. This scale may 

 produce two generations a year in the southern half of Illinois, 

 but usually it produces only one generation a year in the northern 

 half of the state. 



