272 



INSECTS AFFECTING SHADE TREES 



Clip off the galls, if possible, while green and burn them. No 

 other remedial measures are suggested. 



The Cottonwood Scale. These are small, papery, snow-white 

 scales (Chionaspis salicis Linn.). The female scales are larger 

 and more or less pear-shaped. They are found on the branches 



FIQ. 276. Horse chestnut defoliated by first brood of larvae of white-marked tussock moth. 

 (After Houser, Ohio Bull., 194.) 



of the cottonwood and some other trees. Eggs are laid under the 

 female scale in the autumn. They hatch in early summer into 

 small flattened, oval lice. These young lice are very active, 

 spreading over all accessible branches. Like all lice, they weaken 

 the tree by sucking the sap therefrom. 



Control. Kerosene emulsion and whale-oil soap when the 

 young are hatching form fairly effective sprays. The spray should 

 be applied before the insects are protected by a scale. 



