VIEW ARTICLE

Ecology and Epidemiology

Cold Predisposition of Dormant Peach Twigs to Nodal Cankers Caused by Leucostoma spp.. B. N. Dhanvantari, Plant pathologist, Agriculture Canada, Research Station, Harrow, Ont. N0R 1G0; Phytopathology 68:1779-1783. Accepted for publication 24 July 1978. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1978.. DOI: 10.1094/Phyto-68-1779.

Flower bud mortality in selected peach cultivars was correlated with a sequence of low temperatures from –17 to –25 C when dormant twigs were collected in midwinter and so exposed. In repeated trials, samples frozen at various low temperatures contracted a significantly higher number of nodal cankers compared with nonfrozen field samples when artificially inoculated with the canker fungi, Leucostoma cincta and L. persoonii. Among field samples of three peach cultivars collected in late winter, those showing higher incidence of flower bud mortality also showed increased susceptibility to artificially induced nodal cankers. Water leachates of frozen flower buds greatly influenced conidial germination of L. cincta and germ tube growth of both L. cincta and L. persoonii. These results lend support to the view that winter-killed flower buds predispose peach twigs to nodal cankers, which may develop into perennial cankers.