Botanical Abstracts 7(1): 44-45 (February, 1921)

290. Watson, John. Aphis-resistant apple stocks. Nation. Nurseryman 28(9): 213-214. 1920.—The nurserymen of America must come to appreciate to a greater extent the importance of securing nursery stock which will be resistant to aphis injury. The influence of the stock upon the scion as well as the influence of the scion on the stock is recognized. For instance, apple grafts of Bechtel's Crab and of Transcendant will compel a far better root system in two years than scions of Baldwin or Yellow Transparent on seedlings of exactly the same grade.—Of all aphis-resistant stocks the Northern Spy is the best. It is largely used in England, South Africa, Australia, and New Zealand. The suggestion is made that the time will probably come when California will use nothing else. In Australia, where woolly aphis is a prolific pest, the nurserymen have developed more than 25 varieties of resistant stocks, but Northern Spy furnishes fully 95 per cent of the apple stock used.— Methods for propagation of the stock are given, which are much like those used for Paradise and Doucin stocks.—J. H. Gourley.