INSECT PESTS OF OHIO SHADE AND FOREST TREES 289 



host. Usually, however, infestations are sparse. The insect at- 

 tacks the trunk, branches and occasionally the fruit of the host, 

 and like the San Jose scale has a tendency to cause red spots to 

 appear around the point of attack. 



Food plants. — Quaintance and Sasscer (40) list forty plants as 

 hosts of this species. A decided preference is shown for apple, haw- 

 thorn, currant, mountain ash, chokecherry, etc. 



Distribution. — This is a native insect and is found generally 

 distributed throughout the State and the United States. It occurs 

 in both rural and urban districts. 



Natural enemies. — Three predaceows enemies have been re- 

 corded for this species: Tyroglyphus mains Shimer, Hyperaspis 

 sp., and the twice-stabbed ladybird Chilocorus bivulnerus Muls. 

 The following parasitic Hymenoptera have been recorded: Ablerus 

 clisiocampae (Ashm.), Physcus varicornis How. and Prospal- 

 tella sp. 



Control. — The best control method consists in spraying with 

 any of the sulphur sprays or miscible oils in the strength and at the 

 time recommended for the San Jose scale, viz., while the trees are 

 dormant. In addition this species may be controlled by spraying, 

 in late May or early June when the brood of young appears, with 

 kerosene emulsion or whale-oil soap. However, the dormant period 

 is a much more satisfactory time in which to do the work, because 

 it is possible to do more thorough spraying when the tree is free 

 from foliage. 



THE WILLOW SCURFY SCALE 



{Chionaspis salicis-nigrae Walsh) 



Description. — The willow scurfy scale is the largest of the 

 scurfy scales, measuring from one-eighth to one-sixth of an inch 

 in length. The shape is slightly pyriform, and the scale is slightly 

 the widest in the middle. It differs still further from the other 

 scurfy scales in that it has a slightly glossy appearance as if coated 

 with a transparent varnish. (See Plate XLVIII, Fig. 2.) The 

 male scales are much smaller, slender, with almost parallel sides 

 and with the body shghtly ridged. 



The eggs are oval and purplish red and the newly-hatched 

 young are of the same color. 



Life history and habits. The winter is passed in the egg stage. 

 Hatching occurs in late May or early June. There are probably 

 two broods per season. 



Nature of work. — The twigs, branches and trunk of the host 

 are attacked, occasionally with such severity as to cause the death 

 of parts or the whole of it. As a rule, however, it is not so severe 



