OF DWARF FRUIT TREE CULTURE. 103 



water. I have given much thought to this subject, fully perused 

 volumes of correspondence in the horticultural press, and have come 

 to the conclusion that in most cases of canker the state of the roots 

 is the secret of the mischief. Predisposing causes point to the best 

 way of preventing and restricting its work. It will be noticed that 

 canker seldom appears on trees whose roots are all near the surface, 

 but most frequently on trees which have tap roots whose sap is 

 drawn from the sour subsoil which, owing to its depth from the sur- 

 face, has not been "sweetened" by the heat of the sun's rays. The 

 cells of the wood produced by such sap cannot be properly ripened 

 and on the appearance of cold the cells give way, causing the mark 

 to split, the "Nectria" at once enters and canker commences its 

 deadly work. The remedy, or rather the preventive, is to keep the 

 roots near the surface by frequent mulching of stable manure. Can- 

 kered branches should be pared around to the quick and dressed 

 either with clay and cowdung, gas tar or grafting paste. 



Pear Midge This is probably the greatest enemy of the pear. 

 The midge itself is a small knat-like fly, which in April lays its egga 

 in the opening flower buds of the pear tree without in any way pre- 

 venting the fruit from setting. There are no signs of its presence 

 until a few weeks later, when those attacked commence to swell 

 abnormally and to assume deformed shapes. On examination these 

 will be found to contain a number of small worms. It is imperative 

 that all fruits attacked be gathered and burnt, else early in July 

 they will fall to the ground, turn to chrysalis and give a fresh 

 supply for coming seasons. 



Pear Slugs There are several kinds, but the most plentiful are 

 the grubs of the pear and cherry sawfly. They do a great deal of 

 harm, mostly in May, by eating not only the foliage, but also the 

 tips of the growths of pears and plums. Spray with formula D. 



Cracking and Scab occur frequently on trees when the pruning 

 and roots have been neglected. A change of soil at the roots will be 

 needed, but the parasite fungi whose present prevent assimilation in 

 the leaf and development in the fruit can only be eradicated by re- 

 peated sprayings with formula F (including the Paris Green). First, 

 when the buds begin to swell; second, just before the blooms open; 

 third, when the blooms have fallen, and twice later at intervals of a 

 fortnight. 



Mosses, Lichens and Scales It is a pitiful sight to go through 

 many orchards where apple trees in particular have their bark 



