This section is from the book "The Gardener's Monthly And Horticulturist V22", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
There seems to be no doubt but that water, in which Paris green or London purple has been put, and pumped over the trees through a hose from a garden engine when the fruit is first forming, will prove a perfect security against codling moth and canker worm. We do not like the idea of using these poisonous substances in things we directly eat. It does not seem so bad on potatoes, which are in the ground, washed, peeled and boiled before eaten. If exceeding great care be used to apply the poison long enough to get thoroughly washed off by rain before eating, it may do.