This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Prof. Cook, of the Michigan Agricultural College, found that one pound of the powder was effective in two hundred gallons of water when applied for killing cabbage worm. The powder must touch the insect to be effective, and loses its value if left long exposed. Its power is due to a volatile oil. It costs one dollar per pound, so must not be wasted. We should be glad to hear from those who believe in salt for the cabbage worm. If it can be applied without injury to the cabbage, it ought to be all that is desirable.