APPENDIX 453 



completely covered with a white minutely velvety layer of 

 the conidial form of the fungus. When this occurs the 

 fruit is practically useless, being unsightly and also insipid, 

 owing to the greater part of the sugar having been ex- 

 tracted by the fungus. 



Preventive Means. — Great attention is necessary in 

 order to successfully combat the disease. Wherever the 

 fungus is known to exist, or where it was present during 

 the previous season, the foliage should be thoroughly 

 dusted with flowers of sulphur and quicklime, taking care 

 to cover the under surface of the leaves, commencing when 

 the leaves first expand, and repeating at intervals of eight 

 days. By this means the disease is arrested before it 

 passes on to the young fruit. 



The ascigerous form of fruit, which enables the fungus 

 to first start growth in the spring, is rarely if ever produced 

 on the strawberry fruit, but only on the leaves, hence 

 where the disease has previously existed, it would be 

 advisable to burn the diseased foliage as described on 

 p. 1 08. By this means not only are the resting spores on 

 the leaves destroyed, but also those that have fallen to 

 the ground. 



POTATO BLACK-SCAB 



{Oedomyces leproides, Trabut.) 



This fungus, which is described on p. 225 as attacking 

 beetroot in Algeria and France, has recently been observed 

 in various parts of England, causing the formation of a 

 similar disease on potatoes ; a blackish irregularly nodulose 

 scab is produced which often spreads until the entire sur- 

 face of the tuber is covered. 



