450 PLANT DISEASES 



by pruning branches or shoots from the stem should be 

 at once coated with tar. To guard against infection from 

 spores floating in the air, the stem should be coated with 

 a mixture of soft soap, quicklime, and washing soda. 



Diseased plants should be removed and burned without 

 delay. 



The fungus is often very common on blackthorn, wild 

 plum, and bullace, and from thence may pass on to young 

 fruit-trees, hence a sharp look-out should be kept for such 

 diseased plants in hedgerows, etc. 



Massee, Gard. Chron., Sept. 27, 1902, fig. 80. Journ. 

 Board Agric., ix. p. 361, pi. vi. (1902). 



VIOLET DISEASE 



(Phyllosticta violae, Desm.) 



Cultivated violets, especially when forced too much, 

 often suffer from this fungus, which has proved very diffi- 

 cult to check when once established. At first rounded 

 bleached spots appear on the leaves ; these gradually 

 increase in size and often run into each other, forming 

 irregular blotches, which show equally on both surfaces 

 of the leaf. At a later stage very minute black dots 

 appear on the dead bleached spots. These black points 

 are the fruit of the fungus, which consist of hollow recep- 

 tacles containing numerous colourless cylindrical spores 

 which ooze through a minute opening at the top of the 

 receptacle in the form of a minute tendril. 



PREVENTIVE MEANS. Spraying with potassium sulphide 

 will prevent the rapid spread of the fungus, if commenced 

 at the first sign of the disease, which is in most instances 



