Wiktionary
lime sulfur
alt. A mixture of calcium polysulfides used as a fungicide and insecticide on deciduous trees. n. A mixture of calcium polysulfides used as a fungicide and insecticide on deciduous trees.
Wikipedia
Lime sulfur
In horticulture, lime sulfur ( British spelling lime sulphur) is a mixture of calcium polysulfides formed by reacting calcium hydroxide with sulfur, used in pest control. It can be prepared by boiling calcium hydroxide and sulfur together with a small amount of surfactant. It is normally used as an aqueous solution, which is reddish-yellow in colour and has a distinctive offensive odour.