Table 3 Online interviews: themes supporting evidence and researcher interpretations of the data

Perceptions of risk and benefit associated with plant viruses

Perceptions of both risk and benefit, and perception of solely risk associated with plant viruses

‘If it’s a good virus, maybe it can be positive, but 3/4 of viruses, I think they are rather negative’ (P4-Belgium-Female-35–54)

‘….it could potentially lead to benefits as well because I imagine that plants have to develop ways of withstanding the viruses, and hence it might lead to some positive changes where they kind of adapt to these new conditions, so I'm guessing that there could be potential benefits as well’ (P68-UK-Female-18–34)

‘I think on balance they're [the viruses] going to have negative impacts, but there will be some positives as well, because as new viruses attack plants, plants themselves will mutate ….and become stronger themselves, learning too, in a way, to get over what is happening to them’ (P77-UK-Female-55+)

‘The positive impact would be …researchers can sample and study them and can be better at preventing them’(P16-Belgium-Female-35–54)

‘Viruses are used to produce vaccines, and therefore we can do research on the virus to get some benefits…’ (P44-Spain-Female-55+)

‘These [plant viruses] are risks, we no longer know how to eat them when there is a virus and you get sick, probably if you don't know if we are not aware that these are viruses….’ (P2-Belgium-Female-55+)

‘If a plant is infected, it can cause diseases in some humans. So yes, it’s important to take that into account when we consume certain foods, we could be infected with the disease of the plant virus’ (P11-Belgium-Male-18–34)

The most frequently expressed perceived risks associated with plant viruses included those associated with the environmental, plant and human health risks, and economic problems and losses linked to diseased plants. Participants described scenarios where viruses can spread from one plant to another and negatively affect surrounding fields. Some participants believed that eating a plant affected by viruses may produce adverse effects on human health

The most frequently expressed benefits were associated with the perception that plants exposed to viruses can get immunity to them; plants can become stronger; that the study of viruses can inform medical research; and that viral exposure can help crops to develop abiotic stress resistance linked to temperature, and drought tolerance

Negative affect associated with the term virus

Association of plant viruses with negative perceptions and affect

‘…. if I hear the word virus [it] is negative, that's going to be a bad thing. That's going to cause trouble. Whether it wipes out crops, and you know, people go hungry…’ (P62-UK-Female-35–54)

‘The name of virus means poison, so they are bad for everything, for humans, plants, and animals’ (P44-Spain-Female-55+)

‘I’d say I’ve become a lot more worried about anything involving the word virus. Over the past 6 months……’ (P75-UK-F-55+)

The word “virus” evoked negative affective responses for some participants

Awareness of plant viruses

The extent to which participants were aware of the existence and/or impacts of plant viruses

‘…I have heard about viruses. I have also seen some of the viruses ……pictures [of] how this looks and what it does to […] different plants, to the leaves, or to the whole plant or something that is growing, it’s dangerous’ (P40-Slovenia-Male-18–34)

‘You have viruses that create disease problems and those disease are difficult to treat’ (P1-BEL-Male-55 )

‘A virus […] it’s built to survive and therefore it uses the cell of a plant, and it kills the host’ (P41-Spain-Male-18–34)

‘They [viruses] need to enter the cells, and for that normally they enter through insects or wounds and then they infect the plant. They are two kinds of virus, the ones that replicates through DNA and the ones that use RNA’ (P47-Spain-Female-35–54)

‘No, I know very, very little. I just know there can be viruses….’ (P3-Belgium-Female-18–34)

‘I have a very small amount of knowledge…Basic, very basic knowledge, other than living on a rural area where I live’ (P65-UK-Male-35–54)

‘The only thing is I started back when coronavirus basically started hitting the news, I guess […] about January, February time I basically put […] into a search engine about viruses. I can't remember exactly what came up […], all I can remember, very few plant viruses are harmful to the plant itself” (P72-UK-Male-55+)

The range of knowledge about plant viruses and their potential impacts (both negative and positive) varied considerably between participants, with some indicating that they were unfamiliar or unknowledgeable about their existence of their potential impacts, while others had more extensive knowledge about these issues

Perceived control of plant viruses

Identification of which stakeholders should have responsibility for controlling plant viruses

‘Yes. I think they [farmers] should control [plant viruses]…’ (P27-Slovenia-Male-18–34)

‘So, since it has to do with our health, it has to be very well controlled. …. It is the farmer’s job to do that, to make sure that the products he will sell will be good for people who will consume them and who will buy [the products]…’ (P3-Belgium-Female-18–34)

‘…. I think they [farmers] might not have enough information, or they should talk with people specialized in agriculture that can advise them about the causes and solutions and ways to prevent the appearance of viruses’ (P55-Spain-Male-55+)

‘Plant viruses are emerging risks, that’s why we have to control them. I think farmers should continue to control them. It's not just for the national economy, but for them too’ (P10-Belgium-Female-35–54)

‘Organizations can also help them to diagnose viruses and get some cure against the viruses’ (P33-Slovenia-Male-18–34)

‘One way to control them would be making sure that the seeds come from for a good place, …. to follow a quality control, like the meat’(P43-Spain-Female-35–54)

‘Farmers are struggling these days, and they got to try to combat plant viruses, but I see dangers with regard to what farmers will use to try to combat viruses, such as with chemicals and fertilizers. That might actually be worse than the virus itself” (P77-UK-Female-55+)

‘…they [the government] should give help like money or machinery to the farmers so they can control the virus’ (P54-Spain-Female-35–54)

‘They should be providing adequate funding so that science, so that scientists, botanists, and people at local levels can contribute and do what they can to avoid emerging issues with plant viruses…’ (P70-UK-Male-35–54)

‘The government… has a certain responsibility for the health of citizens. So …the government should be…, regulate, …and put in place rules to decrease the risk of viruses’ (P3-Belgium-Female-18–34)

‘Agricultural policy is more of the European domain anyway. I think certainly at the European level that measures must be taken….’ (P8-Belgium-Male-35–54)

Participants expressed the view that farmers should be responsible for controlling risks associated with plant viruses in agriculture, and that the government represents a key stakeholder who should act to reduce negative impacts associated with plant viruses in the food supply chain. This was explained as farmers being in close contact with their fields and these noticing problems first

Participant interest in risk–benefit information about plant viruses

The extent to which participants said they would like to have access to information on the risks and benefits associated with plant viruses

‘Yes, I would like to. It would help to make decision when I get fruit and vegetables’ (P41-Spain-Male-18–34)

‘Yes, I would like to. But specially about the benefits, because personally, I do not know any, but I know about loads of bacteria that are good and give us benefits. There must be a virus that gives some benefits’ (P42-Spain-Male-35–54)

‘Yes …I don't know at all what it is. I may have heard like that, once a virus, but plant viruses I don't know at all what it is so that it would be good to have a little information on this because nobody talks about it’ (P3-Belgium-Female-18–34)

‘We have the right as consumers to know what we eat, and that includes the virus information because we could eat it without knowing’ (P14-Belgium-Male-55+)

‘E-mail, it is easier because you can have a look any time’ (P43-Spain-Female-35–54)

‘Yes, I think that would be helpful. I think that they should have a media campaign on television and on the Internet” (P15-Belgium-Female-35–54)

‘From the government or the farmers since they are concerned by this. (P3-Belgium-Female-18–34)

‘The government [should provide information].. Because they will control and put rules on’ (P43-Spain-Female-35–54)

Government was the most frequently mentioned as preferred communication providers, followed by plant virus experts, farmers, minister of agriculture, and scientists

Which stakeholders are concerned about plant viruses

Farmers were thought to be the most worried stakeholders in relation to plant viruses because agriculture is the basis of the farmers’ livelihood

‘It’s their living anything that's going to affect somebody’s living is going to cause them to worry about it’ (P62-UK-Female-35–54). ‘Yes, because of the quantity of products, but not specifically for the virus. It is more about the money’ (P22-Slovenia-Male-18–34)

‘We eat the viruses, eat the products and have them too, which I think is not good for our health’ (P5-Belgium-Female-55+)

‘I am worried, because if there is a lot of viruses it means the increase in chemicals. I like to buy food without chemicals, locally produced’ (P22-Slovenia- Male-18–34)

‘…Some products could vanish, or the food price can increase to be much higher, like 2000%’ (P21-Slovenia-Male-35–54)

‘It’s not really the government who will suffer an economic impact. It is rather the farmers who go having to bear the consequences. […] So, I don't think government cares really, unless that really affects a lot of farmers at once which is a threat to the environment or a threat for them, for really a large number of farmers’ […] (P3-Belgium-Female-18–34)

‘No, people involved in the food chain are not worried because they don't care. They care only about the profit margins, so they will find another supplier’(P21-Slovenia-Male-35–54)

‘I was not worried until now, but after this conversation, yes. To be honest as I was not informed about this, I have never thought about viruses in plants’ (P58-Spain-Female-35–54)

‘I was not worried, but after this interview yes, a little because it’s a topic that I don’t know much about it’(P52-Spain-Male-18–34)

Farmers, as primary producers, where perceived to be most (negatively) affected by the occurrence of viruses in supply chains