Archivio Journal of Plant Pathology

Abstract:

Nyctanthes arbor-tristis, family Oleaceae (Nyctaginaceae), grown in many Indian garden and temple compounds for its fra- grant blossoms, possesses multiple pharmacological properties (Chopra et al., 1958). A leaf disease characterized by irregular red- dish-brown spots with dark margins and brown to whitish centre was observed during the post-rainy season at Jaipur and Udaipur (India). Adjoining lesions coalesced resulting in large pustules. In- cidence of infection and its severity in the surveyed area were al- most 40 and 30-60%, respectively. Surface-sterilized diseased tis- sue plated on tetracycline-amended (250 mg/l) potato dextrose agar (PDA) yielded grey fungal colonies with a black backside af- ter incubation at 22±2°C for 7 days. Conidiophores were cylindri- cal, straight or curved and unbranched, 3-10 septate, smooth and pale brown. Conidia were isolated or formed acropetal chains, had a variable shape, were 25-190 μm long and 5-10 μm thick, with a rounded apex and truncate base, 5-15 pseudoseptate, yel- lowish brown and smooth. Based on these morphological features, the fungus was identified as Corynespora cassiicola (Ellis and Holi- day, 1971). The identity was confirmed by the National Fungal Culture Collection of India (NFCCI), Agharkar Research Insti- tute, Pune, India (Culture No. OP 98). To confirm pathogenicity, disease-free plants were inoculated with a conidial suspension containing 1000 conidia/ml. Controls were inoculated with sterile distilled water. After 1 week, spots similar to those observed on the original diseased plants appeared on the leaves of inoculated but not in the contro plants. The pathogen was re-isolated from symptomatic leaves, fulfilling Koch’s postulates. C. cassiicola is known as a pathogen to many plants in India (Jamaluddin et al., 2004), but, to our knowledge, this is its first report as a pathogen of N. arbor-tristis in the country.