Crown or collar rot has caused extensive death of apple trees in many eastern orchards during the past two decades. It often occurs on trees between 3 and 8 years of age grown on Malling-Merton 104 (MM. 104), MM. 106, and, to a lesser degree, MM. 111 rootstocks. The disease often affects low areas of orchards having heavy, poorly drained soils, but it can affect all orchard sites if trees are first infected in the nursery.
The first symptoms to …