xviii PLANT DISEASES 



the tips of the shoots, which for a distance of two or three 

 inches present a brown and shrivelled appearance; just 

 the appearance of tips that have been injured by. ' green 

 fly.' On examination of these shoots with a magnifying- 

 glass, the remains of the brownish matted mycelium of the 

 fungus can be seen, studded with a number of black 

 points, which are the winter form of fruit. 



All such diseased tips should be removed during the 

 winter; the prunings, bearing the fungus, should be col- 

 lected and burned, and not dropped on the ground, accord- 

 ing to custom. During winter, before the buds begin to 

 swell, spray thoroughly with a solution of sulphate of 

 copper, one pound of sulphate dissolved in twenty-five 

 gallons of water to which a small quantity of soft soap is 

 added. Bordeaux mixture may be used instead of the 

 sulphate of copper solution. In the spring, just when the 

 leaf-buds are expanding, spray with a solution of potassium 

 sulphide (liver of sulphur) in water. In America it has 

 been found that half an ounce of potassium sulphide 

 dissolved in a gallon of water kills the mildew. If this 

 strength of solution, is found to scorch the foliage, more 

 water must be added ; in fact it would be advisible to try 

 first one ounce of the sulphide in three gallons of water. 



A 'CLUSTER-CUP' DISEASE OF CONIFERS 



(Calyptospora Goeppertiana, Tubeuf.) 



' Cluster-cups ' is the popular name of one of the stages 

 in the life-cycle of many members of the group of fungi 

 known as rusts, of which rust of wheat is a well-known 

 example. All the rusts without exception grow on living 



