COTTONY MAPLE SCALE 



287 



great loss to the lumber industry. It appears to be increasing 

 and spreading over a large territory. 



Its control in the forest probably depends upon encouraging 

 its natural enemies, animal parasites, and fungus pests. Orna- 

 mental larch trees may be sprayed with arsenate of lead. 



Cottony Maple Scale (Pulvinaria innumerabiles Rath.). The 

 adult insect is nearly one-half an inch long and the scale is oval. 

 It is conspicuous because, from underneath it, protrudes a mass of 

 white cottony secretion in which the eggs are laid (Fig. 290). 

 The young lice hatch in the spring and early summer, migrating 



FIG. 290. Cottony maple scale. 



at once to the leaves, and there becoming temporarily attached. 

 A number of moults occur while they are on the leaves. Fertili- 

 zation of females by males occurs here, the impregnated female 

 migrating to the twigs. The following spring the developed eggs 

 cause the body of the female to increase in size. Late in spring 

 and early summer these eggs are laid in the cottony growth above 

 referred to. One female may produce from one thousand to two 

 thousand eggs. 



Injury. This pest is at times injuriously abundant on maples 

 and elms, as well as various shrubs and vines. It may occur on 

 oak, basswood, locust, sumach, woodbine, currant, and other 



