Page:The Olive Its Culture in Theory and Practice.djvu/153

Rh tissues and of the regenerating zone has the same effect that the puncture of an insect would, and at times produces the enlargement of the zone and sometimes the enlargement of the herbaceous tissues. These enlargements in time extend to the wood under the bark and cause the bark to draw away thus affording a receptacle for different insects. This would however be an effect and not a cause of the evil. Some orchardists remove the protuberances by shaving them off with a sharp knife, but this does not restore the tree to health as this cutting does not remove the primary cause. The first method for its cure is to keep the trees wide apart, well lighted, to prune sparingly, and to abolish the barbarous usance of beating the trees when gathering the berries. Senor Tablada says he found an insect eight hundredths of an inch in length in the act of making these warts and cured the tree by cutting them off.

THE OLIVE ROT. (See Plate XVI.) The rot is the gangrene which appears on the trunk and larger branches of the olive tree. At times it is so extensive as to consume nearly all the cylindrical part of the wood leaving the larger branches hollow and rendering them an easy prey to the action of the winds. When a wound is made on the olive tree either by the breaking of a limb or by pruning, and is not at once shielded from contact with the air, a process of canker is initiated, provoked by the humidity found there, the action of insects and the spores of certain lichens or creepers. Trees improperly pruned are usually the ones attacked by the rot. To prevent it, an olive orchard should be placed on well drained soil and receive plenty of light. The trees should not be bruised and when a branch is cut off the wound should be immediately covered with grafting wax or a mixture of cow dung and clay. When the rot has taken hold the diseased part