356 
Cultivation and Management of Hops. 
Mould {White Blight or Mi/dew) .—This white blight was more 
dreaded than the black blight. As to the latter, there was a 
chance of a thunder shower, or other atmospherical agencies, 
clearing it off; but when once the former had appeared it usually 
went on with its work of destruction until the bitter end.* 
Now this was, until lately, thought to be the result of a morbid 
state of the tissues of the hop plant ; whereas the microscope has 
proved beyond a doubt that it is a fungus, whose spores are 
floating about in the air, ready to develope themselves wherever 
and whenever the fitting conditions of food and temperature are 
offered them.j Mr. Cooke, the careful mycologist, classifies this 
fungus as Spha;rotheca Castagnei, of the group Erysiplie, and 
states that it is a common form found upon hops, meadow-sweet, 
and various other plants. It is allied to the rose mildew, 
Spharotheca pannosa. The vine disease is another form of an 
ErysipJie, and all these, as Mr. Cooke states, " are not in them- 
selves perfect plants, but merely conditions of other fungi of 
a higher order, little differing, it is true, in external appearance 
to the naked eye, but offering material differences in structure 
under the microscope.^ This dimorphic habit of parasitic fungi 
was noticed by Professor Henslow years ago, especially with 
regard to Uredo and Piiccinia graminis, as to the one form 
being capable of development into the other,§ and the doctrine 
of alternation of generation of fungi has been lately further illus- 
trated by Dr. A. de Bary, and by observations made in France 
by M. Piret, both of whom have ascertained that one of the fungi 
which produce the rust in cereals, the Puccinia graminis, and the 
fungus which causes the well known orange spots on the leaves 
of the Berberry, the dJcidium Berherridis, are, in reality, different 
forms of the same plant ; the spores of which will not reproduce 
itself, but the other form. || So that farmers were not altogether 
wrong in their prejudice against the Berberry, nor hop-growers 
in their decrees of banishment against this and other plants and 
trees from the vicinity of their hop-grounds. 
Looking at all these revelations of science, it is wonderful that 
mould is not more prevalent in hops ; and it is fortunate 
that an almost certain preventive against, and destroyer of, these 
fungoid growths has been discovered in sulphur, which has 
* Mr. Buckland, in his prize essay in the ' Eoyal Agricultural Journal,' in 
1845, upon the Farming of Kent, writes of the mould in hops, that "its causes and 
nature are very little known, and the means of preservation is a matter involved 
in even greater obscurity. Its destruction of the crop is frequently complete." 
t Carpenter's ' Principles of Physiology,' par. 272. 
X Cooke's ' Microscopic Fungi,' (Hardwicke), p. SS. 
§ ' Annals of Natural History,' vol. vi. ; also Carpenter's ' Principles of Phy- 
siology ' on the same subject. 
11 See ' Journal of Botany ' for 18C6 ; and the ' Quarterly Journal of Science ' 
for April, 1870. 
