DISEASES AND INSECTS. 109 



as under the most skilful management some trees 

 become diseased. 



Gumming sometimes takes place in previously 

 healthy trees. An exuberant flow of sap will some- 

 times result in gumming. Severe pruning of a 

 vigorous-growing tree would, I should say, also 

 cause gumming in due time. On the other hand, 

 a healthy, vigorous-growing tree, which has been 

 properly managed during active growth in the way 

 of disbudding and stopping of extra strong growths, 

 if not by removing them altogether, so as to direct 

 the flow of sap into the weaker growths, thereby caus- 

 ing an equal distribution among all the branches, 

 will not be affected by gumming. An indiscriminate 

 use of animal manure in the soil when planting 

 would tend to gumming in time. Where gumming 

 does take place, the best thing to apply in the shape 

 of a remedy is to wash off the gum with a brush 

 and clean water, and afterwards dust over the 

 affected portion or portions with freshly slaked 

 lime, repeating the operation if necessary. 



Mildew (" Ordium Tuckeri ") is destructive if not 

 taken in hand as soon as it appears. The affected 

 leaves should be dusted over while damp with 

 flowers of sulphur. Trees growing in cool houses 

 are liable to the attacks of mildew in dull weather, 

 the young foliage being the first to develop the 

 fungus, which appears in the shape of a white 



