MILDEW ON THE BLACK CURRANT.
BY REV. W. STEWART DARLING, TORONTO.
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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