HANDBOOK OX IXSECT ENEMIES OF FLOWERS AXD SHRUBS 41 



Figure 66. — Twigs showing dogwood 

 club galls. Natural size. 



Treatment. — No satisfactory means 

 of preventing infestation is known. On 

 small trees isolated from other infested 

 dogwoods, however, cutting off and 

 destroying the galls soon after they have 

 formed or before the maggots have left 

 them late in the summer will hold an 

 infestation in check. 



Dogwood Scale 



Trunks and limbs of dogwood heavily 

 infested with the dogwood scale (Chion- 

 aspis corni Cool.) have a whitish, scurfy 

 appearance from the numerous scale 

 insects attached to the bark. This 

 scale insect resembles the scurfy scale 

 shown in figure 78. The female scales 

 are roughly pear-shaped, grayish, and 

 about ho inch long, whereas the male- 

 are narrow, with sides parallel, and pure 

 white. The winter is passed in the egg 

 stage under the female scales. When 

 numerous, these small sucking insects 

 weaken the trees or kill the heavily 

 infested branches. 



Treatment. — Apply an oil spray or 

 a lime-sulfur spray, diluted for dormant 

 spraying, in the spring just before new 

 growth starts. The young usually 

 begin hatching when the leaves are 

 about ] 2 inch long, and many of them 

 can be killed by making two or more 



applications of a nicotine sulfate and 



| soap solution or a single application of 



white-oil emulsion (p. 100 about 10 



days or 2 weeks apart. 



Other Pests of Dogwood 



Page 



Leaf hoppers 10 



Mulberry whitefly 22 



' (ystersheU scale 56 



San Jose scale 57 



Melon aphid 90 



Cottony maple scale 47 



EUONYMUS 



Euonymus Scale 



The euonymus scale (Unaspis euo- 

 nymi (Comst.)) is a widespread and seri- 

 ous pest of both deciduous and ever- 

 green species of euonymus. It also 

 infests bittersweet and pachysandra. 

 When numerous, these tiny sucking 

 insects may coat both stems and leaves 

 and seriously weaken or kill the plants. 

 The female scale is flattened, roughly 

 pear-shaped, brownish, and about Yi G 

 inch long. The male scale, however, is 

 white and narrow. These white scales 

 often look like frost on the green leaves 

 (fig. 67) and stems. The insect appar- 



Figurb 67. — Leaf infested with the 

 euonymus scale. About 3 times 

 natural size. 



