82 Proceedings 
fungus then lives on the dead material, Most of the forms 
are unable to penetrate the living cell until they have germ- 
inated first on some waste material such as withered leaves, 
&c., then after a short period of vigorous growth, the 
hyphe are able to pierce the cells of the living tissue. 
This fact was emphasized strongly in a paper published 
lately on a disease of haricot beans. The writer says that 
he does not think the Botrytis could at once attack 
healthy pods, but the spores alight on some vegetable 
remains such as withered petals which might be still adher- 
ing to the immature bean. ‘They thus get a start on the 
dead vegetation and then attack the living plant. The Lily 
Botrytishas exceptionally large conidia, full of food material, 
and Marshall Ward says, on this account, they can at once 
germinate and enter the host plants without any organic in- 
termediary. The killing of the tissue by the poison excreted 
accounts for the rapid destruction of the plants attacked. 
The number of plants that are subject to disease of 
Botrytis or Sclerotinia is very large and varied, There are 
the lily and its allies ; beans and potatoes have their stalks 
destroyed ; whole fields of clover are laid waste by one 
form, and another causes a disease of the vine. Paonies 
and gooseberries, and even lime trees, are attacked in the 
stems just at the surface of the ground, and it is a virulent 
disease of seedling pines. Besides all these cases, Botrytis 
vulgaris is one of our commonest moulds and grows every- 
where as a harmless saprophyte on decaying vegetation. 
No account of plant diseases is satisfactory without a 
suggested cure ; the remedy in this case is a drastic one. 
All diseased plants should be burned, care being taken that 
no part of the diseased tissue is left behind. Then the 
crop should be changed and the fungus left to die of 
starvation for want of its particular pabulum. Fungicides 
are of little avail, as the fungus has penetrated too deeply 
into the tissue ; in the case of sclerotia, they would have 
no effect whatever. Partial sterilization of the soil has 
been recommended, that is putting a surface layer of sterile 
sand on the diseased area. It seems more practicable and 
safer to change the crop. 
