Latest News

Tomato Brown Rugose Fruit Virus

Tomato Brown Rugose Fruit Virus

 tomatoes rugnose

When tomato brown rugose fruit virus (ToBRFV) strikes, it can quickly infect 100% of a crop and cause yield losses of between 25% and 70% due to the fruit of tomatoes and sweet peppers being unmarketable and reduced production as plants suffer lack of vigour and die prematurely.

Its potential economic impact on commercial production is significant due to reduced crop quality and yield. In addition to the hit on income, the virus also brings the additional costs of removing infected crops and cleaning the glasshouse.

ToBRFV is a member of the genus Tobamovirus. This genus also includes other tomato-infecting viruses such as tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV). Unlike these viruses, however, ToBRFV can overcome the Tm-22 gene, so tomato varieties that are resistant to TMV and ToMV can be infected.
Origin and distribution

First seen in crops in Israel in 2014, ToBRFV was found in Jordan in the following year and since then has spread to other tomato production areas around the world, including China, France, Greece, Italy, Mexico, the Netherlands, Spain and Turkey. There have also been outbreaks in Germany and America, but these have been eradicated.

An outbreak was confirmed in a tomato glasshouse in south-east England in 2019 and phytosanitary measures were taken, and it was declared eradicated. However, in 2020 there were a further five outbreaks in the UK. These were declared eradicated last year.

Additionally, ToBRFV has been intercepted on imported tomato and pepper seed. Defra points out that the virus is likely to be more widespread than currently reported. It is recommended that the EPPO Global Database (https://gd.eppo.int) be checked for full records.


Identification

Although the name “tomato brown rugose fruit virus” is taken from the brown, wrinkled (rugose) patches that can appear on infected fruit, symptoms are more characterised by general discolouration, including chlorotic marbling and dark spots, along with uneven ripening, deformation and reduced size of fruit.

Symptoms on the leaves include subtle to severe mosaic patterning as well as leaf deformation, puckering, narrowing, blistering and reduced leaflet size. Plants may wilt and necrosis can develop on stems, calyces, petioles and flowers.

Tomato rugose foliage connell university

But — and it is a big but — like Covid-19, ToBRFV may show no obvious signs of infection. Susceptibility of the crop is dependent on the variety, cultural practices and the climate. The virus can also remain active on surfaces including steel, concrete and polythene.


Life cycle/spread

ToBRFV can be transmitted through sap transfer and by contact. It is also transmitted via seed — both tomato (Solanum lycopersicum) and pepper (Capsicum spp.) — although it is thought that it is restricted to the seed coat and does not infect the seed embryo. However, it should be noted that the virus is capable of surviving on the seed coat for several years. Although strongly suspected, transmission from the seed coat to the seedling is thought to be inefficient and has yet to be demonstrated experimentally.

The virus enters plants through wounds and reproduces within the plant cells using the cells’ own replication mechanisms. The virus can move from cell to cell or over longer distances via the plant’s phloem to infect all parts of the plant. All parts then become a source of contamination. Growers should be aware that handling the fruit of an infected plant will enable the virus to be passed to other plants. The virus has also been shown to be transmitted by bees during pollination.


Control/management

Control is challenging because ToBRFV is environmentally stable and also relatively heat-tolerant. Since 1 January 2021, the Plant Health (Phytosanitary Conditions) (Amendment) (EU Exit) Regulations 2020 have been in force, including measures on imported tomato and pepper seed and plants for planting to prevent the introduction and spread of ToBRFV. In addition, AHDB has formed a ToBRFV steering group to help form a response to, and mitigate, this virus threat from a UK perspective.

Surveillance is crucial and a programme has been scheduled for spring this year, taking in tomato and pepper production nurseries, production facilities and packing sites, with sampling and testing of plants and fruit combined with tracing activities where necessary.

Hygiene and biosecurity are paramount. There are no treatments available for ToBRFV. The only way to eliminate the virus from a crop is to remove and destroy the affected plants and then follow good hygiene practices. The best means of prevention is to use virus-free planting material.
Essential details

Hosts

The main hosts of ToBRFV are tomato and pepper, although it is useful to note that pepper varieties with the L1, L3 and L4 genes appear to be resistant. However, it is likely that other solanaceous species could be hosts for the virus, including Solanum nigrum, S. melongena, Chenopodium giganteum, C. murale, C. quinoa, Petunia × hybrid, Nicotiana benthamiana, N. Clevelandii,
N. glutinosa and N. tabacum. Weeds are also deemed potential reservoirs.

Reporting

England and Wales: suspected findings of ToBRFV should be notified immediately to the local Animal & Plant Health Agency plant health and seeds inspector or the Plant Health & Seeds Inspectorate headquarters in York (email: This email address is being protected from spambots. You need JavaScript enabled to view it.; tel: 01904 405138).
In Scotland, contact the Scottish Government’s Horticulture & Marketing Unit (email: This email address is being protected from spambots. You need JavaScript enabled to view it.; tel: 0131 244 8923).
In Northern Ireland, contact the DAERA Plant Health Inspection Branch (email: This email address is being protected from spambots. You need JavaScript enabled to view it.; tel: 0300 200 7847).

#The pest status of ToBRFV in the UK has officially been declared as 'absent, pest eradicated', after sites where the virus had previous been present were shown to be clean and free of the virus, according to a report on the EPPO Global Database.

201203 ToBRVF ir 1 1920x1080

BASF have released the above variety, claiming it has intermediate to the viral disease

 

© Hort Week 2022 For much more information please subscribe to the magazine for online and printed information

Image

thedrurys.com is designed and maintained by Darren Hodson - Kavanos Web © 2024, The Drurys

Search