French authorities have warned farmers and gardeners to exercise "extreme vigilance" after a deadly virus that targets tomatoes, chillis and peppers was potentially discovered at a farm in Finistere.

In a statement released on Sunday, France's Agriculture Ministry warned vegetable producers and amateur gardeners to wash their hands immediately after touching tomato seeds, seedlings and fruits in order to stop the spread of the virus.

It also demanded they check that seeds and seedlings had been declared free of the disease before buying them. The virus presents no risk to humans.

The warning came after the ministry confirmed "a very strong suspicion of the ToBRFV virus" on tomatoes in greenhouses on a farm in Finistere, in the south-west of the country.

Analysis is being carried out to verify whether the tomatoes have been infected, with the results expected next Monday.

In the meantime, the two greenhouses are being confined and access to them is restricted, all the plants, seeds and fruits have been consigned and biosecurity measures have been set up.

Small abrasions

The National Agency for Food Safety (ANSES) first raised the alarm about the virus on February 3, noting that pepper bells and chilli are also particularly vulnerable to the disease.

'Tomato brown rugose fruit virus' (ToBRFV) was first detected in 2014 in Israel and in Jordan the following year and spread to a dozen more countries with cases spotted in Germany, Italy, the Netherlands, Greece, the UK and Spain.

It infects the fruit through small abrasions caused by contact with plants, hands, tools, clothing, insects, birds or irrigation water.

"The virus can infect up to 100% of plants on a production site, which makes it formidable for crops with high planting density such as in greenhouses," ANSES said in a statement.

"However, all tomato crops can be impacted: conventional, organic farming, in integrated biological protection, in greenhouses and in the open field."

The ministry warned in its statement that the spread of the virus across the country "would have major economic consequences" for the sector.

The French consume 13.9 kg of tomatoes per household per year, while 712,000 tonnes were produced in 2018. It is also widely cultivated in a vegetable garden with nearly 400,000 tonnes produced each year.