Winter Meeting. 307 



'^i> 



tion of gum upon the twigs, branches, and even upon the trunks of the 

 trees. There are no perforations of the bark as are made by the Bark 

 Beetle. The gum hardens and becomes conspicuous. The dis- 

 ease appears at all seasons of the year, but is most manifest when 

 the leaves are off the trees. In general, the exudation occurs near the 

 leaf scars of the previous year. Following the continued exudation of 

 gum, enlargements form at many of the affected points. These en- 

 largements are often great enough to be mistaken for Black Knot. 

 Sectional examination of the diseased branches generally shows a 

 dead or injured area. In the region of the dead or injured area we 

 find gum pockets, and the}- continue apparently while growth lasts. 

 The real cause has not been discovered. When a tree is badly affected 

 by this disease, it is probably best to destroy it by burning. Where or- 

 chards are slightly affected, it may be worth the while to try close pruning, 

 drainage, if necessary, and thorough cultivation. 



TWIG SPOT— BROWNING OF GREEN BARK. 



In uncultivated orchards spotting of the twigs is frequent. Many 

 specimens show definite spots in which the epidermis has turned down, re- 

 sembling Anthracnose spots on the raspberry. Such spotting is very 

 general. No fungus or other organism has been found to occur con- 

 stantly in the spots, and the practice of cultivation and good care causes 

 much of it to disappear. A normal cork growth, however, should not be 

 mistaken for fungus or for a diseased condition. 



CROWN GALL. 



This disease manifests itself in enlargements upon the roots and 

 stems of the tree, but with a decided tendency to occur at the crown of the 

 tree. These galls are visually soft, corky or spongy growth upon the 

 various parts of the tree. Below ground the galls are renewed with each 

 season's growth, the old galls falling away and decaying while new 

 ones are formed. When new, the galls are externally of the same color 

 as healthy roots. This formation of galls continues until the death of 

 the tree, which usually occurs in from one to three years. 



Excision of these galls seems to have no influence whatever in the 

 way of eradicating the trouble. No matter whether but a single gall 

 appears upon a small root, or large ones upon the main stem, the whole 

 tree seems to be in a diseased condition, and as the old galls are taken 

 off, new ones appear. The disease appears to be communicable over 

 short distances in the soil, and the soil will remain infected for some 

 time after the removal of the diseased trees. 



