First Report of Cristulariella moricola on Kenaf in Georgia. R. E. Baird, Plant Pathology Department, The University of Georgia, RDC, P.O. Box 1209, Tifton 31793. Plant Dis. 79:425. Accepted for publication 28 February 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0425C.
Kenaf (Hibiscus cannabinus L.) plants being grown at the Southwest Branch Experiment Station, Plains, GA, were observed to have brownish discolored lesions present on over 80% of the leaves. The field containing the kenaf was within 100 m of two pecan (Carya illinoensis (FA. Wangen-heim) K. Koch) orchards with 5% of the leaves containing zonate leaf spot lesions. Using a l0 x and lens, conidiomata of Cristulariella moricola (Hino) Redhead were observed within the lesions on kenaf. Isolates of the fungus were obtained from diseased tissue to confirm the pathogen's identity. In previous studies, C. moricola was reported to cause zonate leaf spot on pecan (1) and was also isolated from kenaf (2) in South Carolina. To confirm pathogenicity of C. moricola, isolate Cr 1 obtained from diseased kenaf tissue at Plains was inoculated onto the cultivars C 108, Cubano, Ev. 41, Ev. 71, SF 459, Tainung #2, PI 468074, 075, 076, and 077. The isolate was cultured on potato-dextrose agar and 5-mm mycelial plugs, taken from actively growing margins, were placed onto leaves either nonwounded or punctured with a needle. Noninoculated controls for each cultivar were included for comparison. After 7 days of incubation in moist chambers at 18-25 C, both wounded and nonwounded inoculated leaves for all cultivars had foliar symptoms resembling the lesions previously observed at the Plains field station. Reisolation of the fungus from the necrotic tissues confirmed pathogenicity. The noninoculated controls did not develop foliar symptoms. The experiment was repeated and similiar results occurred. It is unknown whether strains of C. moricola from kenaf can cause disease on pecan trees.References: (I) A. J. Latham. Phytopathology 59:103, 1969. (2) J. H Blake et al. Plant Dis. 78:102, 1994.