INSECT PESTS OF OHIO SHADE AND FOREST TREES 291 



one-eighth of an inch long, plainly convex and when removed from 

 the bark a conspicuous white scar remains. The male scale is 

 white, slender and with three distinct ridges extending lengthwise 

 of the body. (See Plate XLIX, Fig. 3.) The eggs are ellipsoidal 

 and purplish. 



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

 the young appear in late spring and two generations are produced 

 annually. 



Nature of work. Twigs, branches and large limbs of the host 

 are attacked. Young trees are killed outright sometimes, but on 

 older trees the injury assumes the form of a lowering of the general 

 vitality of the host and a killing of smaller branches, thus causing 

 it to assume a ragged, frowsy appearance. 



Food plants. American elm (Ulmus americana) , Camper- 

 down elm (Ulmus scabra pendula) and Ulmus montana var. cam- 

 perdown pendula are attacked by the elm scurfy scale. 



Distribution. This species occurs throughout Ohio, and in all 

 situations where its hosts are found. 



Natural enemies. The larva and adult of the ladybird, Chiloc- 

 orus bivulnerus, have been observed feeding on this species and two 

 parasites, Perissopterus pulchelhis and Physcus varicornis have 

 been bred from it. 



Control. The sulphur sprays or the miscible oils applied in the 

 normal dormant strengths before the buds break in the spring are 

 specific control agencies for this species. 



THE PINE LEAF SCALE 



(Chionaspis pinifoliae Fitch) 



Description. Tiny, elongate, white objects with a yellow 

 pellicle attached to one end found infesting pines and some other 

 conifers usually are the scales of the pine scurfy scale. The females 

 average about one-eighth of an inch long and the males are smaller. 

 The females vary in width, depending upon the host. For in- 

 stance, when the species is found on the slender needles of the white 

 pine the female scales are very slender, but when infesting other 

 pines with broader needles or other species of conifers, usually the 

 scales are broader. (See Plate XLIX, Fig. 1.) 



The purplish eggs, 20 to 30 in number, are found beneath the 

 parent mother scale. 



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

 the young hatching in May. Egg-hatching extends over a con- 

 siderable period. By late 'summer, the first individuals of the first 

 brood have matured and eggs for the second brood are deposited. 

 There are two broods per year in Ohio. 



