Diagnosis of sharka (plum pox) and host range of its inciting virus

Diagnosis of sharka could be improved by distinguishing specific and unspecific symptoms. Two types of discoloration (broad red bands and thin red rings and lines) were specific, whereas the grooves and pits were not. Light and electron microscopy revealed the presence of nuclear and cytoplasmic inclusions in infected tissues. The cytoplasmic inclusions (bundles of needles) in plum fruits were reliable for diagnosis.

From the known herbaceous test plants Chenopodium foetidum and Nicotiana clevelandii, only C. foetidum was useful for diagnosis. Ranunculus arvensis and Nicandra physaloides were presented as possible new test plants.

Sixty herbaceous plant species were described as host of sharka virus. Some common weeds became systemically infected upon inoculation and may play a role in epidemiology of the virus.

Purified sharka virus was used to prepare antisera. Some properties of the virus were described.