THE OLIVE 



123 



The black fungus is due solelv to local causes. There is either 

 too much dampness pr not enough light. The infected branches 

 should be cut off and burned and the tree sprayed with kerosene as 

 heretofore described. Xo olive tree on ground high enough for a 

 sufficiency of air and ventilation was ever afflicted with this pest. 

 The cultivation of the soil provokes moisture and stimulates the 

 vegetable growth of the tree, so where the black fungus appears, 

 cease this cultivation, do not stir up the soil, but on the contrary 

 check the excessive growth and humiditv, by allowing; the surface 

 ■of the ground to harden. Prune the trees so that each may have a 

 maximum of light and air. If the excess of moisture cannot be 

 remedied by these means, the soil must be drained. 



VISCtTM ALBUM, MISTLETOE. 



The mistletoe is propagated from one tree to another by its seed. 

 It extends its green roots through the branches from which it draws 

 its nourishment, greatly enfeebling the tree. The only method of 

 destroying it is, to cut off the branches on which it has effected a 

 lodgment, and burn them. 



LICHENS AND MOSSES. 



It is erroneously claimed by many writers that the mossy sub- 

 stance which grows upon the trunk and branches of the olive and 

 other trees is a parasite. Instead it is composed of moss and lichens, 

 the principal ones of which are Parmelia. Lecanara, Verrucaria, etc.. 

 among the lichens, and Hypsum, Leskea, Bryum and Orthotrichum 

 among the mosses. 



These last are cormus fungi, and all are epiphytes and live on the 

 outside of the dead bark and exercise no parasitical influence. They 

 shield the bark from the sun. but the humidity they engender is a 

 frequent cause of rot, and they also serve as nesting places for hurt- 

 ful insects. For these reasons it is well to liberate the trees from 

 them by scraping the infected parts, or spraying with a solution 

 of lime. 



