This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
We understand that there is great probability of an effectual remedy for mildew and red spider having been discovered, wholly free from the objections attaching to sulphur either in powder or in a volatile state. How valuable that agent is we all know; but it is troublesome to apply, uncertain in its action, and, if mismanaged, more mischievous than the evils it counteracts. As for example when it is fired, the effect of which is to charge the atmosphere with fumes of sulphurous acid, one of the most fatal to vegetation of all known substances.
At present our information amounts only to this: that Mr. Wilson, the very able and scientific manager of Price's Candle Company, has prepared a soap, which being dissolved in water and applied with a syringe does effectually and without the least risk, all that flour of sulphur can do. It is said that one of the principal nurserymen near London has been trying the soapy water, of different strengths, and is very favorably impressed with its efficacy. Six ounces of the soap in a gallon of water killed mildew for the time and continued to keep it down when applied weekly. Pot Roses after three applications became nearly clean, and were in fact saved; their soft young points indeed were killed, but that was of no importance; the rust of Moss-roses disappeared before its action. In other hands red spider was effectually kept down; 1 lb. of the soap dissolved in 4 gallons of water completely cleaned even Peach trees after two or three applications, the trees having been well syringed a day or two afterwards.
The name of this new soap or substance is, we are informed, "The Gerhurst Compound,*' and if it is found in other hands to preserve the good qualities now ascribed to it, Mr. Wilson will certainly have conferred one of the greatest possible benefits upon horticulture. A trial is about to be made of it in the Garden of the Horticultural Society, at Bowood, Trenthatn, Chiswick House, and several other large establishments; but, owing to the lateness of the season, we fear that no good results can be looked for at present. - Gardener's Chronicle.