Abstract
Indexing of a number of apple (Malus sylvestris (L.) Mill.) cultivars and rootstocks in New Zealand has shown a high incidence of infection of chlorotic leaf spot, stem pitting, stem grooving, and M. platycarpa dwarf and scaly bark viruses. The high incidence of infection in apple trees is believed to have been caused by the working of new cultivars on infected rootstocks or to top-working of infected orchard trees.