I should be glad if in the next number of the HORTICULTURIST the editor
would say whether he has seen or heard of a sort of blight or mildew
which here has fallen on the black currants, and which, if it spreads,
will put an end to the culture of that fruit. I have some beautiful
black Naples bushes from which I have never had any perfect fruit;
although a man who knows something about it said the other day, I ought
to have half a bushel of currants from each tree. Soon after the foliage
is fully developed, I observe here and there that the leaves begin to
assume an upright tendency around the edges; underneath I find an almost
invisible film, which however is so slight that I can assure myself of
its presence only by passing my fingers over the under side of the
leaves, after which there is a perceptible “stickiness,” which contact
with healthy leaves does not produce. This continues to increase till
the film becomes white, and passes over on to the upper side of the leaf
in the form of mildew. This subsequently becomes brown, and the leaf, or
part of it, will crumble as if scorched with fire. The power of the leaf
is evidently destroyed before this stage; the fruit is arrested in its
growth, and even that which is tolerably matured is dry and almost
useless. I can detect no trace of insect life, nor could a well-known
entomologist, who looked at them last summer, suggest the cause. I
treated them with whale-oil soap in strong solution, and though I
fancied that it retarded the growth of the evil it had no ultimately
good effect. I have cut them back rather closely and propose to try salt
on one row and sulphur on another. The land is light and warm, but well
enriched; but land equally poor, not far off, had good fruit on it,
while mine yielded nothing.
Not only in my own interest, but in that of others, I should be glad if
some of our skilled fruit growers could give their attention to this
matter.
[NOTE.—Not having noticed this mildew, the editor requests any
members who have been troubled with it to give their method of
treatment.]
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