DESTRUCTIVE INSECTS. 



163 



and is easily killed with kerosene emulsion, a strong soap so- 

 lution, or a tobacco decoction applied in a forceful spray. The 

 root form is much more difficult to reach. Badly infested 

 nursery stock should be destroyed. The roots of slightly 

 affected stock should be dipped for a few seconds in water 

 kept at a temperature of 1 30 to 1 50 F. , or in a warm, strong 

 soap solution, before it is planted. Recent experiments show 

 that finely-ground tobacco dust is very effective if placed in a 

 small furrow along either side of nursery rows or distributed 

 at the rate of from two to five pounds per tree for a distance 

 of two feet from the crown, after first removing from four to 

 six inches of soil. The tobacco dust is cheap, and has consid- 

 erable fertilizing value. 



The Round-Headed Apple-Tree Borer {Saperda Candida). 

 — This insect enters the tree and burrows into the solid wood 

 near the surface of the earth. It is a dangerous enemy ; for 

 while only a few small holes are visible in the bark outside, 

 it may have perforated 

 the wood internally in 

 all directions. 



Not only the apple- 

 tree, but the quince, 

 mountain-ash, and haw- 

 thorn suffer greatly from 

 the attacks of this in- 

 sect. 



The parent insect is 

 a beautiful, brown-and- 

 white striped beetle 

 (Fig. 215), about three- 

 fourths of an inch long, 

 which flies at night. It 



deposits its eggs in June and later in slits cut in the bark, 

 usually near the surface of the ground. The egg-stage is 

 said to last about twenty days. The first indication of the 

 work of the larva is the appearance of a small round hole, 

 made visible by the ejected dust. 



The young larvae tunnel under the bark and feed upon the 

 sapwood, gradually working tlieir way upward and afterward 

 downward. During the second season the larvae attain about 



Figs. 213 and 214. Fig. 215. FIG. 216. 



The Round-headed Apple-tree Borer. 

 Figs. 213 and 214.— The grub. FIG. 215.— The 



beetle. Fig. 216.— The pupa. All natural size. 



(U. S. Div. o£ Entomology.) 



