Its resistance to woolly aphid is derived from M. sieboldii , rather than Northern Spy. It shows good tolerance to Peniophora and Phytophthora . Difficult to propagate by conventional stoolbeds. There are other Aotea rootstocks but most produce vigorous or very vigorous trees. M.26 and MM.106 have both been successfully grown in the UK without stakes when budded high and deep planted, where there were adequate windbreaks.
Deep planting can, however, slightly delay early growth and cropping.
Despite the efforts of rootstock breeders we do not yet possess a complete range of size controlling rootstocks that also exhibit resistance to woolly apple aphid and soil borne diseases. Interstem trees , although more expensive to produce than normal trees, do offer the advantage of linking a root system that is resistant to soil borne diseases with an interstem of a dwarfing rootstock to produce a composite tree with the required combination of characters. Interstem trees also offer a relatively simple way of using difficult to root rootstocks, that have otherwise useful characteristics. Some researchers have, however, noticed an increase in root suckers when a dwarfing interstem is used with a root system of a vigorous rootstock. Canada - Robusta 5, the Ottawa and Vineland series.