THE APPLE-ROOT BLIGHT. 459 



ble to borers, or to some unfavorable condition of 

 the soil, it very probably results from the attacks 

 of the little woolly louse named above. 



In the autumn the female of this species pene- 

 trates the earth, following down near a root, deposits 

 her egg^, and dies. As these eggs hatch, the young 

 insinuate their beaks to the liber of the roots, and 

 draw from them the sap, upon which they subsist. 

 This irritates the part, and induces a greater flow 

 of sap to that point, and causes little excrescences to 

 be formed upon the roots, from a very small size to 

 that of a pea. It is very evident that these excres- 

 cences must very seriously weaken the tree, if they 

 increase to any extent. The larvae are almost in- 

 visible to the naked eye, being not more than four 

 hundredths of an inch in length. From the tip of 

 the abdomen protrudes a short thread of " cotton-like 

 matter, variously curled and crinkled. This renders 

 them more perceptible. The insect afterwards be- 

 come winged, attains a quarter of an inch in length, 

 and is covered with a mass of white down." 



The disease which they joroduce is often seen in 

 its primary stages in young trees as they come from 

 the nursery, and can be detected by the excres- 

 cences upon the roots. Thousands of trees have 

 been uselessly thrown away as valueless when 

 this has been found to be present. Dr. Fitch sug- 

 gests that if these roots were immersed in, or 

 washed with, a strong solution of soft soap, the in- 



