Insect Damage 53 
involve the water-supply, the supply of oxygen, and the 
supply of nutritive elements. 
The most common symptom of unfavorable soil condi- 
tions is found in the paling or eviolation of the leaves, which 
become prematurely yellow, wilting and falling before the 
end of the season; while in other cases the leaves and buds 
are reduced in size. SBranch-tips, especially of horizontal 
branches, are killed back, and the top of the crown dries 
and dies, giving rise to the so-called sfaghead; or else water- 
sprouts, slender, long, wisp-like shoots out of the regular 
order, are formed. Excessive growth of moss and lichen 
may also be an accompanying symptom. 
If the tree has been vigorous before, and has only recently 
shown signs of weakness, we must note especially any 
changes lately made in the soil conditions, which may 
account for change in its vigor; such as the cutting down 
or filling up of ground, making ditches, laying gas-pipes, 
draining or flooding, cultivating or sodding, performances 
which are apt to interfere with the root system, altering its 
environment, and hence the amount of active root growth. 
If none of these investigations give a clue, we must then 
inquire into the weather conditions and the history of the 
preceding two, three, or four seasons, as well as into sur- 
roundings generally, and we must ascertain what has been 
the previous treatment of the patient. 
Thus circumspect investigation and observation and 
historical evidence must be brought together to diagnose 
the more complicated cases, while in other cases the initiated 
may be able at once to determine the cause of the abnormal 
condition. The novice will have to examine with more care, 
especially to avcid the mistake of recognizing as the pri- 
mary cause what is only secondary. 
Insect Damage. The most obvious damage is that done 
