New disease of tomato in Israel caused by a strain of Tomato apical stunt pospiviroid: addition to the EPPO Alert List
In spring and summer 1999 and 2000, tomato plants showing stunting, leaf deformation, yellowing and brittleness were observed in a few commercial plastic houses at different locations in the coastal region of Israel. Fruits were considerably reduced in size with a pale red discoloration. In all cases, the disease spread rapidly mainly along plant rows, resulting in a disease incidence of nearly 100% and heavy yield losses. Molecular assays revealed the presence of Tomato apical stunt pospiviroid (TASVd) in diseased tomato plants.
TASVd was first found and characterized in Ivory Coast, but no data was given on its epidemiology or economic impact. Another strain was found in Indonesia but again without data on potential economic impact. Cloning and sequencing of viroid RNA showed that the Israeli strain has 92% identity with the type strain (Ivory Coast) and 99% with the Indonesian strain. The experimental host range and symptomatology of the Israeli strain also differed from those of the type stain. Under experimental conditions, the Israeli strain of TASVd was readily transmitted from infected to healthy tomato plants by grafting or mechanical inoculation. Further studies are needed on possible pollen or seed transmission.
Tomato apical stunt pospiviroid (a new disease of tomato)
Why: Tomato apical stunt pospiviroid (TASVd) came to our attention because it is reported as a new and serious disease of tomatoes in Israel.
Where: Israel (found on tomatoes grown under plastic houses in the coastal region). TASVd was first described in Ivory Coast and another strain was reported from Indonesia. However, data is lacking on the extent, severity and economic impact of the diseases it may cause.
On which plants: Tomato (Lycopersicon esculentum). Data is lacking on its host range.
Damage: Affected tomato plants in Israel showed shortened internodes (bushy appearance), leaf deformation and yellowing, reduced fruit size, pale red discoloration of fruit. Up to 100% disease incidence could be observed with heavy yield losses.
Transmission: TASVd can be transmitted from infected to healthy tomato plants by grafting or mechanical inoculation (in experimental conditions). No data on pollen or seed transmission.
Pathway: Plants for planting of tomatoes, fruits?, from countries where TASVd occurs.
Possible risks: Tomato is an important crop in the EPPO region, both indoors and outdoors. Data is lacking on geographical distribution, host range, epidemiology of TASVd. As control of viroids is difficult in practice, it would be desirable to avoid any further spread of a potentially serious disease of tomatoes.
EPPO RS 2003/109
Panel review date - Entry date 2003-07
Antignus, Y.; Lachman, O.; Pearlsmand, M.; Gofman, R.; Bar-Joseph, M. (2002) A new disease of greenhouse tomatoes in Israel caused by a distinct strain to Tomato apical stunt viroid (TASVd). Phytoparasitica, 30(5), 502-510.