252 PLANT DISEASES 



mixture when the leaves are expanding, and again at 

 intervals if the rust appears. Fallen diseased leaves 

 should be thoroughly cleaned up and burned. 



The fungus is often common on the leaves of the black- 

 thorn, and care should be taken not to allow this plant to 

 act as a nurse to the fungus, and thus constitute a centre 

 of infection. 



Prillieux, Malad. des Plantes Agric., vol. i. p. 241. 



HOLLYHOCK BUST 



(Pucdnia malvacearum, Mont.) 



This rust is a native of Chili, and first appeared as a 

 pest in Australia, soon afterwards entering Europe through 

 France, and at the present day is to be met with wherever 

 the hollyhock is cultivated, and in addition having victim- 

 ised the wild mallows and allied plants during its distri- 

 bution. This disease, at the time of its first appearance, 

 rendered almost impossible the successful cultivation of 

 the hollyhock ; but with the progress made during recent 

 years in the methods of arresting plant diseases, it can 

 now be cultivated with success. 



The teleutospore phase is the only one formed, and 

 this appears on the leaves under the form of minute, hard, 

 pale brown warts ; in many instances the stem, also the 

 calyx and fruit, are studded with pustules. These teleuto- 

 spores germinate without a period of rest, the secondary 

 spores produced continuing the disease. It has been 

 stated that the teleutospores formed late in the season 

 act as resting-spores, not germinating until the following 

 season. 



PREVENTIVE MEANS. Spraying with Bordeaux mixture 



