Potato spindle tuber disease is caused by (a) Phycobionts (b) Virus (c) Bacteria (d) Viroids
Viroids. In 1971, studies of the potato spindle tuber disease showed that it was caused by a small, naked, single-stranded, circular molecule of infectious RNA, which was called a viroid (see later). Viroids have been found to be the cause of several dozen plant diseases.
