REPORT OF THE APPLE AND PEAR CONFERENCE. 



50 



substance. Parasites may again be divided into those of a fun- 

 goid nature and those that are green. 



Mildew affecting the apple is a white mould belonging to the 

 group Erysiphe, and in this, the early stage, it is referred to 

 the genus Oidium. It is one of the most easily destroyed of 

 parasitic fungi, from the fact that it lives on the surface and does 

 not penetrate its host. Sulphur alone, or various preparations 



containing sulphur, will completely destroy the fungus. Should 

 a large number of trees in a garden or orchard become affected, 

 the application of sulphur would be a tedious and costly opera- 

 tion ; but if a few isolated trees only are attacked, the remedy is 

 more easily applicable. 



Cracking is caused by Cladosporium dendriticitm, a too widely 

 prevalent fungus, that grows on the leaves, young shoots, and 

 flowers of the apple, often preventing the formation of fruit. In 

 severe cases the latter becomes partially or completely covered 

 with blotches, crippling and preventing it from attaining full 

 size, and in all cases the fungus reduces the market value of the 

 produce by disfiguring or causing it to crack. The disease com- 

 mences as black spots, branching from the centre like a small 

 tree, while on fruit the patches soon become irregularly rounded, 

 with a depressed black spot in the centre, surrounded by a white 

 line, and that again by a black border. The pear is attacked in 

 the same way by a variety of Cladosporium dendriticum, generally 

 known amongst fungologists under the name of Cladosporium 

 pyrorum. No remedy is known, and means to prevent it spread- 

 ing must be adopted by destroying badly affected trees and fruit. 



MILDEW ON APPLES. 



