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Ecology and Epidemiology

Infection Site, Infection Period, and Latent Period of Canker Caused by Anisogramma anomala in European Filbert. T. R. Gottwald, Research plant pathologist, USDA-SEA-AR, Southeastern Fruit and Tree-Nut Laboratory, Byron, Georgia 31008; H. R. Cameron, professor of plant pathology, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Phytopathology 70:1083-1087. Accepted for publication 15 May 1980. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-1083.

Ascospores suspended in sterile distilled water were hypodermically infiltrated into buds infested with Phytocoptella avellanae and into noninfested buds resulted in 46.5 and 29.0 percent infection, respectively. Infection in buds not infested with P. avellanae was attributed to mechanical injury during inoculation. There was a general increase in percent infection as inoculation dates approached the normal infection period from February through late May which was determined from disease incidence in trap plants. Infection was correlated with the duration of rainfall during the same season. Ascospores were recovered on slides exposed to 10 mature cankers continuously from each of 10 different exposure periods from 26 November to 3 April. The data indicate that the period of spore release is at least 6 mo in duration, extends well beyond the spore-trapping dates, and thus lasts much longer than the natural infection period. Heaviest discharge was recorded during periods of constant wetting of the stromata. Following infection there was normally a 12–16 mo latent period for symptom expression in the orchard. Under greenhouse conditions symptoms developed within 6 mo of inoculation. Phomopsis was isolated frequently from both cankered and healthy tissue, so it is unlikely that it is involved in the Anisogramma anomala canker syndrome.