274 LANDSCAPE GARDENING. 



prove effectual in destroying many of the larvae as they 

 work their way into the tree. 



CANKER- WORMS (Anisopteryx pometaria and Palceacrita 

 vernata), Figs. 157 and 158. These insects extend over a 





% 6 



FIG. 157. CANKER-WORM. 



(Riley Circular No 9, 2d Series, Dept. Agr., Fig. 1.) 



wide area of the country, and are very injurious to the elm, 

 apple, and some other trees. The male (a) insect is a grayish 

 moth of about -J- inch stretch of wings and flies in the night, 

 while the female (b) has no wi ngs. The female crawls up the 

 tree and lays its eggs in clusters on the branches during the 

 night at any time from October 15th to April 15th when the 

 ground is not frozen and in warm, moist, nights. The eggs 

 hatch out about the time the buds unfold, and unless 

 destroyed the larvae soon eat all of the leaves but the 

 skeleton and midrib, giving the trees the appearance of a 

 fire having burned off the foliage. 



Remedy. The remedy so generally used of putting bands 

 of tar or printer's ink, or of tin or other kind of troughs 

 with oil in them, around the trees to prevent the female 

 insects from reaching the branches is effectual provided 

 the band is kept covered with soft ink or tar or the trough 

 is well filled with oil when the insects are moving, i.e., at any 

 time when there is no frost in the ground, on warm nights 

 from November 15th to April 15th. The more satisfactory 

 remedy, except for very tall trees, however, is to give the 

 insects no attention until the eggs begin to hatch out, and 



