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an extended application, for it is indisputable that the spores of 
many of our fruit tree pests such as Monzlza, various Erisyphe, 
etc, rest during the winter in the crevices of the bark, or even 
between the bud scales and in hchens on the trunks, where they 
might readily be disposed of by the thorough application of 
fungicides. Under such circumstances there need be no hesita- 
tion in employing solutions which in the case of an actively 
growing tree might do more harm than good. We no longer 
have to consider, for instance, the scalding effect of some of the 
commoner reagents employed on the foliage. Thus the bark 
of a resting tree may safely be sprayed heavily with a ten per 
cent. solution of ferrous sulphate without experiencing any ill 
effects. If on the other hand this solution was applied to a tree 
in full activity the foliage would be destroyed. 
Many of our worst plagues cannot unfortunately be attacked 
in so simple a fashion, and methods have to be resorted to for 
exterminating the parasite or its reproductive spores whilst it 
is in active growth on the host plant itself. For this purpose 
various fungicides are employed either in a liquid or a solid 
state. In such cases as the diseases brought about by the 
mildews Erisyphe, Sphaerotheca, Phyllactinia, etc., where prac- 
tically the whole of the mycelium is on the surface of the host 
plant, the direct destruction of the fungus is an easy matter. 
For this purpose flowers of sulphur, either alone or mixed with 
two parts of fresh lime, may be dusted over the diseased por- 
tions of the plants, special brushes or bellows being made for 
the process: The dressing is an effective one, but its mode of 
action is not yet understood; it may be merely mechanical or 
it may be that toxic substances are produced in minute traces 
which kill the mycelium outright. Among the parasites which 
may be destroyed in this way are the grape mildew Uncinula 
spiralis, the rose and peach mildew Sphaerotheca pannosa, the 
hop mildew S. castagnez and so on. 
Where deep seated mycelia like those of the rusts or of the 
Peronosporeze and various Ascomycetes have to be dealt with 
liquid fungicides may be employed more satisfactorily. In such 
cases attention has to be directed to the crops of spores the 
mycelium produces rather than to the direct destruction of the 
mycehum itself. From time to time numerous fungicides have 
rn recommended. For the most part they are preparations 
of Copper or iron salts, less frequently permanganate of potash, 
sulphide of potassium or lysol are employed. None of these 
bid fair to Surpass in general usefulness the original prepara- 
tion of copper sulphate and lime known as “ Bordeaux mixture.” 
This was discovered accidentally, and we have.to thank 
Millardet for the instantaneous recognition of the possibilities 
opened up. He applied it first of all to vines, and finding it 









