VIEW ARTICLE

Virginia Crab Apple Decline. H. E. Waterworth, Research Plant Pathologist, Plant Science Research Division, ARS, USDA, Glenn Dale, Maryland 20769; Phytopathology 62:695-699. Accepted for publication 26 January 1972. DOI: 10.1094/Phyto-62-695.

The Virginia Crab apple decline agent was detected in 13 apple introductions from European countries and Australia. It incited a conspicuous yellowing of the foliage of Virginia Crab, but not of other apple virus indicator varieties. Trees that decline over a 2- to 3-year period usually bear a premature crop of small fruit on a stunted tree. Golden Delicious and Malus platycarpa (Long Ashton clone) were stunted and fruited precociously. The Virginia Crab scions were swollen immediately above the graft union, and necrotic phloem tissue developed at the interface of stock and scion. Most of the isolates that induced decline of Virginia Crab also induced stem pitting or stem grooving in this indicator.