Lethal Yellowing of Java Citronella (Cymbopogon winterianus) Caused by Pythium aphanidermatum. M. Alam, Scientist, Department of Plant Pathology, Central Institute of Medicinal and Aromatic Plants, Post Bag No. 1, P.O. RSM Nagar, Lucknow 226016, India. A. Sattar, K. K. Janardhanan, and A. Husain. Scientist, Scientist, and Emeritus Scientist, Department of Plant Pathology, Central Institute of Medicinal and Aromatic Plants, Post Bag No. 1, P.O. RSM Nagar, Lucknow 226016, India. Plant Dis. 76:1074-1076. Accepted for publication 30 March 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-1074.

Pythium aphanidermatum was the predominant fungus recovered from the roots of Java citronella showing lethal yellowing in the northern part of India. The disease occurred most frequently between July and October. Roots of infected plants showed marked discoloration, and the cortical region was completely disintegrated and sloughed from the vascular tissue. Diseased plants were chlorotic and stunted. Rotting was often found to spread from roots to stem, leading to severe chlorosis and death of the infected plants. The pathogenicity of the fungus was established. The disease is a potential constraint to citronella cultivation in nonarid climates where the crop is irrigated extensively.