This section is from the book "The Gardener's Monthly And Horticulturist V21", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
We have been favored with advance sheets of the Michigan Pomologi-cal Society's last meeting in which was a prolonged discussion on the Peach Yellows. An interesting letter from Mr. Byron D. Halsted, who has made minute fungi a close study, was read, in which he says: "The peach curl is caused by a fungus, Ascomyces deformans, but that this is the same species as the yellows I do not know." The "curl" fungus has nothing to do with the yellows, which, as already stated in our magazine, is caused by the mycelium of a species of Agaricus. It rarely develops into a perfect "toad-stool," though in the writer's carefully conducted experiments he has bred them. The spawn attacks health living roots and permeates the tree through all its parts, and the "filaments of some fungus" found in the wood by Mr. Halsted, were probably of this species. Budding therefore will communicate the disease. A knife used on a diseased tree may carry it, the fallen leaves of a diseased tree blowing under a healthy one will carry the threads into the soil, and the peach stones of a diseased tree may travel and carry the fungus a thousand miles.
In an orchard where the diseased trees exist the hoe-harrow spreads the disease very rapidly from the roots of one tree to the roots of another, and even where the soil is not disturbed much the spawn spreads under ground from tree to tree. If the members of the Michigan society had done what several years ago we recommended our readers to do, dig out a shovelfull of earth from around a tree afflicted with yellows, and put it in the ground around a tree that is perfectly healthy, they will soon see that the cause of the disease is as "clear as the noonday sun." It would be a surprise to us that an experiment so reasonable should not be made long before this by those who are interested in the knowledge, did we not know from past experience that a Large number of people in the world will talk for hours and write for weeks, rather than spend five minutes with their hands and eyes in experiment and observation.