VIEW ARTICLE

Resistance

Effect of Inoculation Date on Induction of Resistance to Cytospora in Italian Prune Trees by Cytospora cincta. Hugh Randall, Former Graduate Assistant, Department of Plant & Soil Sciences, University of Idaho, Moscow 83843; A. W. Helton, Plant Pathologist, Department of Plant & Soil Sciences, University of Idaho, Moscow 83843. Phytopathology 66:206-207. Accepted for publication 27 June 1975. DOI: 10.1094/Phyto-66-206.

Six-year-old Italian prune (Prunus domestica) trees were infected with Cytospora cincta on eight separate occasions during a single growing season and reinfected two weeks later to evaluate the magnitude of the Cytospora induced-resistance reaction when initiated at different times of the year. Strong, season-long resistance was induced by May infections; unusually strong resistance resulted from July infections. This suggested that studies requiring long observation periods therefore should be initiated in May (under Moscow, Idaho, conditions) and those requiring highest levels of induced resistance should be initiated in July.