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of the tree in early summer. However serious the out- 

 break of the disease and the resulting defoliation may be, 

 the tree generally attempts by the formation of new 

 leaves to compensate itself for the foliage lost. In ex- 

 treme cases of defoliation it is not uncommon to see a 

 tree with an entirely new foliage covering in midsum- 

 mer. In most cases tlie second growth of leaves is not so 

 badly injured by the disease as was the first and it may 

 entirely escape the attacks of the disease. 



It is plain therefore from what has been paid that the 

 general effect of the disease upon the tree is much the 

 same as defoliation due to any other cause. The effect 

 of such a disease upon the life of the tree may best be ap- 

 preciated when one recalls the fact that one of the most 

 important functions of the leaves is to elaborate witliin 

 their tissues the food material for use by the various parts 

 of the plant in the building up of new tissues and other 

 purposes. Even the roots are dependent upon the leaves 

 for the food required for their growth and the defoliation 

 of the tree may result in the most serious damage to the 

 root system of the plant. Defoliation may result also in 

 the great reduction of the growth in diameter of 

 the stem, and particularly in the reduction in the amount 

 of reserve food material stored up in stems, roots and 

 buds for the following year's growth. 



The second growtli of leaves results from the proleptic 

 development of buds intended for the following year's 

 growth. And since, as just stated, these buds have had 

 stored in them less food than usual owing to the dis- 

 eased condition of the foliage of the tree, it is natural 

 that the second growth of leaves developing from them 

 should not be so luxuriant as was the first leaf covering 

 of the tree. Under such conditions, therefore, the tree 

 enters upon the second year's growth with a very small 

 supply of reserve food material. The cumulative effect 

 of the disease may therefore result in many cases in the 

 death of the tree from actual starvation. It is very rare 



