VIEW ARTICLE

Ecology and Epidemiology

The Effects of Pruning on Incidence and Severity of Zygophiala jamaicensis and Gloeodes pomigena Infections of Apple Fruit. C. M. Ocamb-Basu, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616; T. B. Sutton(2), and L. A. Nelson(3). (2)Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616; (3)Department of Statistics, North Carolina State University, Raleigh 27695-8203. Phytopathology 78:1004-1008. Accepted for publication 11 March 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-1004.

The effectiveness of apple tree pruning as a management tactic for control of flyspeck (Zygophiala jamaicensis) and sooty blotch (Gloeodes pomigena) was investigated at four orchards during 1983–1985. The 1983 growing season was hot and dry, rainfall was near normal in 1984 but temperatures were below normal in July and August, and the 1985 growing season was characterized by above normal rainfall and slightly below normal temperatures in July and August. The incidence and severity of sooty blotch were less in pruned trees than unpruned trees in 1984 (P= 0.10) and 1985 (p=0.01) when data were averaged across locations and sampling periods. There was no significant difference between the treatments in 1983. Sooty blotch severity at harvest averaged 9% less in the pruned trees than the unpruned ones over all locations during 1984 and 1985 seasons. The effect of pruning on flyspeck incidence and severity was not clear. The incidence and severity of flyspeck were significantly greater (P= 0.05) in the pruned treatments in 1984; there was no difference between the treatments in 1983 and 1985.