New Zealand tomato exports to six countries have been stopped, after the _Pepino mosaic virus_ (PepMV) was discovered on crops. The Ministry for Primary Industries (MPI) has notified Australia, Japan, Thailand, Fiji, Tonga, and New Caledonia, because these countries consider PepMV a quarantine risk.
The virus was first detected in an Auckland glasshouse and has subsequently been found in tomato production facilities in the wider region. The premises where PepMV has been found are able to continue selling fruit under strengthened hygiene conditions. The risk of transmission through fruit is considered low.
TomatoesNZ have developed advice for growers. "Now the virus has been confirmed in several facilities, it is considered possible that it may be distributed more widely in the country. We strongly encourage all growers of tomatoes to follow careful biosecurity procedures," they say. The virus can be asymptomatic or have very mild symptoms so it is important to remain vigilant with hygiene, especially with equipment, plant material and people that are moving on and off site.
[_Pepino mosaic virus_ (PepMV, genus _Potexvirus_) was first identified on pepino (_Solanum muricatum_) in South America. It is spreading in the Americas and Europe and has also been reported from a few locations in Asia and Africa. PepMV can also infect potato and aubergine [eggplant], but serious symptoms appear to occur only in tomato. Symptoms may include blotches and scarification on fruit; mottling, distortion, necrosis on leaves and young shoots. The virus can cause significant economic losses, especially in glasshouse tomatoes, due mainly to reduction of fruit quality.
PepMV spreads very rapidly and is highly contagious. Specific insect vectors have not been identified. The virus is transmitted by mechanical means (including contaminated tools, human and insect activities, plant-to-plant contact), grafting and with infected plant material (including insufficiently cleaned seed batches containing contaminated plant debris). True seed transmission (that is, via the embryo rather than the seed coat) is uncommon in potexviruses and appears unlikely for PepMV, but more studies are needed. Disease management is usually focused on phytosanitation and use of certified clean seed and tomato explants.
Different strains of the virus exist for pepino and tomato. Coinfections have earlier been reported with _Potato virus S_ (genus _Carlavirus_) and _Tomato torrado virus_ (genus _Torradovirus_). Most recently, coinfection with the newly identified _Tomato brown rugose fruit virus_ (genus _Tobamovirus_) was reported (ProMED post 20191029.6751082); it was thought that the observed symptoms on tomatoes may have been due to either virus or to synergism. Further studies are needed to clarify the effects of these interactions of PepMV with other viruses on crop damage.
PepMV symptoms on tomato:
Healthy pepino plants:
Additional news stories:
https://www.freshplaza.com/article/9333888/pepmv-brings-a-halt-to-new-zealand-tomato-exports/ (thanks to G Jackson, PestNet)
Information on PepMV:
https://gd.eppo.int/taxon/PEPMV0 (with pictures),
https://link.springer.com/article/10.1007/s10658-015-0664-1 and via
Virus taxonomy via: