This fungicide is not a boiled solution, as might be inferred from the name. It is in reality a mixture of lime and sulfur resulting from the violent action of slaking lime in the presence of finely divided sulfur. It was devised by Scott about 1907 for spraying peaches to protect them from the Brown Rot. When properly made it is the safest and most efficient fungicide for the summer spraying of peaches.

Prepare self-boiled lime sulfur as follows: place ten pounds of sulfur and ten pounds of stone - lime in a barrel. Add cold water slowly to slake the lime, keeping the mass wet but not submerged. Stir occasionally. Part of the large lumps of lime may be kept out at first and added after slaking has progressed to some extent, thus prolonging the slaking and heating. When slaked, dilute at once to fifty gallons, and apply as in the case of bordeaux.

Soda sulfur compounds of various types and under various names are on the market. They are probably as effective as the lime sulfur compounds, but are more likely to cause injury to the foliage. They must generally be used in greater dilution and may not be combined with arsenate of lead. The so-called "soluble sulfur" and "sulfocide" are of this type.