HOCKINGS' GARDEN MANUAL. 



69 



Diseases : Plant healthy trees in well-prepared, well- 

 drained land, and they will not be troubled much with 

 disease. If a tree gets wounded, or a large limb has 

 to be cut off, trim the wood and bark smooth, and 

 cover the part with a mixture of Stockholm tar and 

 grease, 



When the American blight appears on apple trees 

 it should be immediately exterminated, as it is most 

 destructive if allowed to spread, which it will do very 

 rapidly if its progress is not arrested. The blight is 

 caused by an insect which pierces the bark of the tree, 

 sucking the juice and causing wounds which ulcerate 

 and corrode through all the sap-vessels, destroying the 

 branch attacked. The presence of the insect is indi- 

 cated by a quantity of cottony matter attached to the 

 branches, which, on being touched, communicates to 

 the finger a disgusting, chocolate-colored stain. The 

 most diseased of the small branches should be neatly 

 pruned off and burned. The older portions of the tree 

 should have the blight scraped off with a piece of iron 

 hoop, the earth being removed about the trunk of the 

 tree, and all suckers carefully cut away close to their 

 origin. The whole tree, especially the diseased parts, 

 should then be scrubbed with a dandy brush, soaked in 

 warm brine, having some potash or soda dissolved in 

 it, taking care that all the crevices of the bark are 

 thoroughly explored by the hairs of the brush. Some 

 use warm lye, turpentine, ammoniacal liquor from the 

 gas-works, and kerosine. The roots exposed to view, if 

 diseased, should be treated in a similar manner. The 

 ground all round the tree, as far as the roots are con- 

 sidered to extend, should be soaked with strong drain- 

 ings from a dung heap, to poison whatever insect life 

 had escaped the brine, and to stimulate the roots of 

 the tree to new and healthy growth. If the tree is 

 old and the soil exhausted, the latter should be renewed, 

 being replaced with charred rubbish, old turf, the 

 clearings of a muck pit, &c. It has been recommended 



