Susceptibility and resistance of citrus genotypes to Alternaria alternata pv. citri

A survey of citrus cultivars in Israel in orchards where Alternaria brown spot was common on Minneola tangelos (mandarin x grapefruit), revealed the occurrence of the disease as typical foliar and fruit lesions on Dancy and Ellendale (mandarins), on Murcott tangor (mandarin x sweet orange), on Nova and Idith (mandarin hybrids), on Calamondin, and on Sunrise and Redblush (grapefruit). Isolates of Alternaria alternata from each of these hosts were proven to be pathogenic to Minneola tangelo. The host range of A. alternata pv. citri from Israel was assayed by inoculating leaves of diverse citrus genotypes. Several mandarins and their hybrids (Dancy, Kara, King, Wilking, Satsuma, Minneola, Orlando, Mikhal, Idith, Nova, Page, Murcott), grapefruit (Marsh seedless), grapefruit x pummelo (Oroblanco), sweet orange (Shamouti, Valencia, Washington navel) Calamondin, and Volkamer citrus were susceptible. Several mandarins and their hybrids (Clementine, Avana, Yafit, Ortanique), Cleopatra, one sweet orange cultivar (Newhall), pummelo (Chandler), lemon (Eureka), Rough lemon, Rangpur lime, sweet lime, citron, limequat, sour orange, Troyer citrange and Alemow were resistant.