Resistance of Citrus Rootstocks to Phytophthora citrophthora During Winter Dormancy. Ö. Tuzcu, Associate Professor, Department of Horticulture, University of Çukurova, Adana, Turkey. A. Çinar, Professor, Department of Plant Protection, University of Çukurova; M. O. Göksedef, Research Plant Pathologist, Regional Plant Protection Institute; M. Özsan, Professor, Department of Horticulture, University of Çukurova; and M. Biçici, Teaching Research Assistant, Department of Plant Protection, University of Çukurova, Adana, Turkey. Plant Dis. 68:502-505. Accepted for publication 16 December 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-502.

Resistance of 70 citrus genera, species, and cultivars to Phytophthora citrophthora was investigated during winter dormancy. Aeglopsis chevalieri; Citrus yatsushiro; C. sulcata; C. aurantium ‘Alibert’ and ‘Granito’; C. reshni ‘Kibris’; Poncirus trifoliata ‘Yerli,’ ‘Jacobson,’ ‘SEAB,’ ‘Luisi,’ ‘Rubidoux,’ ‘Benecke,’ ‘Rich,’ ‘Ferme Blanche,’ ‘Troyer’ citrange, and C. ampullaceae were found to be very resistant. Citrus celebica; C. aurantium ‘Cardosi,’ ‘Santucci,’ and ‘Curaçao’; C. pennivesiculata ‘CRC’; C. depressa ‘CRC’; Carrizo citrange, C. trifoliata ‘Menager’; C. wilsonii; and C. webberi ‘SRA’ were resistant. C. keraji; C. nobilis; C. aurantium ‘Azaguie’; C. trifoliata ‘Christian,’ ‘Town,’ and ‘Yamagushi’; C. assamensis; and C. micrantha were very susceptible. C. aurantium ‘Yerli’ showed medium resistance and ‘Okan’ was susceptible. Among the citrus rootstocks used widely, C. taiwanica, C. macrophylla, C. aurantium ‘Brazilian,’ and C. junos were ranked as susceptible to P. citrophthora.