Viroids are the smallest agents known to be pathogenic to plants. Unlike viruses, they are devoid of a protective protein coat and are composed entirely of circular ribonucleic acid of low molecular weight (ca. 85,000-130,000 d. In spite of their small size, viroids cause serious diseases of avocado, chrysanthemum, citrus, coconut, cucumber, hop, potato and tomato. Although viroid diseases have...

Background and Aims: Viroids are smallest known plant pathogens and cause several economically significant diseases. Until recently, viroid detection relied mainly on biological tests and indexing. Today various diagnostic techniques such as nucleic acid hybridization, southern blot and reverse transcription coupled with polymerase chain reaction (RT-PCR) are being used for detection and diagno...

Background and Aims: Viroids are smallest known plant pathogens and cause several economically significant diseases. Until recently, viroid detection relied mainly on biological tests and indexing. Today various diagnostic techniques such as nucleic acid hybridization, southern blot and reverse transcription coupled with polymerase chain reaction (RT-PCR) are being used for detection and diag...