134 FRUIT CULTURE UNDER GLASS. 



greasy hands, toucliing them with the hair of the head 

 while thinning them, cold currents of air when the 

 vines are young, and overmuch moisture in the air. I 

 have no recollection of being conscious that rust was 

 produced by any of these causes, though I think too 

 much moisture in the atmosphere as likely to do so 

 as any of them, seeing that it has an effect on the 

 leaves somewhat allied to rust on the berries. The 

 only case of rust worth the name that ever took place 

 in my own experience, was in a very narrow vinery, 

 where, to keep up the heat, hard firing had to be 

 resorted to. Eed- spider under these circumstances 

 made its appearance, and I had the pipes covered with 

 sulphur to check the spider. The grapes were then 

 almost ready to thin: in two or three days after the 

 sulphuring process, the bunches all over the house 

 were more or less blackened. As the berries grew 

 the rusting became more apparent. Whatever else 

 will produce rust, sulphuring hot pipes while the 

 grapes are young will produce it. There is no cure 

 for it after it is produced that I know of. The best 

 thing to do when it occurs before the grapes are 

 thinned, is not to be in a hurry to thin, and to re- 

 move the bunches and berries most affected. 



Excrescence on the under sides of the leaves. — This 

 consists of a mass of watery-like excrescences resem- 

 bling small green boils or blisters, thickly set on the 

 under sides of the leaves. They are produced by a 

 warm atmosphere too highly charged with moisture in 

 conjunction with too little ventilation. I have seen 

 some very inveterate cases of it this very damp sunless 

 season (1872), and, as editor of the 'Gardener,' have 

 had numerous examples of it sent for inspection. It 

 can be prevented by not allowing too much moisture 



