Anti-viral technologies can reduce pathogen transmission in the greenhouse

Three new anti-viral technologies could help prevent the transmission of both COVID-19 and a plant virus that affects tomatoes in commercial greenhouses.

That’s according to a recent Ontario Greenhouse Vegetable Growers (OGVG) research project to refine and apply technologies used in other industries to greenhouses to test their effectiveness at inhibiting virus transmission. The project included three approaches developed by service provider PRODIGie — Innovation Evolved Inc.

Why it matters: The anti-viral technologies are not chemical-based and offer a solution to the spread of viruses with the added benefit of not requiring lengthy regulatory approvals. They could offer a solution for preventing the spread of the tomato brown rugose fruit virus.

Ontario’s greenhouse vegetable growers have been dealing with tomato brown rugose fruit virus, which was first detected here in 2019. It causes distortion of leaves and brown, wrinkly spots on the fruit, making them unmarketable.

The virus can survive for long periods on surfaces away from tomato plants and can be easily picked up by people, tools and equipment, which increases the chance of infection and spread through the greenhouse.

COVID-19 has been a threat to human health, food security and business continuity since it emerged on the global stage early in 2020.

With both pathogens, time was of the essence to minimize spread and impact. Funding from the Greenhouse Competitiveness and Innovation Initiative helped OGVG test various anti-viral technologies as possible tools to control pathogen spread.

“The rugose virus appeared almost in tandem with COVID-19 and commonly used disinfection tools like rubbing alcohol, for example, don’t work on either of these viruses,” says Niki Bennett, OGVG’s lead for innovation, adaptation and plant protection.

“Biosecurity is about keeping things out and preventing transmission and this project gave us a unique opportunity to go after both pathogens.”

Cold-spray coatings

The first anti-viral technology tested, novel composite cold spray coatings, can be applied to static objects like door handles and other high touch areas. According to Bennett, it performs like a barrier to prevent microbial adhesion and provides some antimicrobial activity.

Since it’s not a chemical and not being applied to plants, it does not have to go through a regulatory process to be approved for sale.

The studies showed up to a 97 per cent reduction in rugose virus on surfaces where the cold spray coatings were applied. This was a 10-fold increase in effectiveness compared to current copper benchmarks.

“We don’t know of anyone doing this; that’s what sparked our interest in this solution,” Bennett says. “It’s a barrier method that provides passive, preventative protection.”

Hand cleaners

The second technology evaluated was a non-alcohol, oil-based hand rub with antimicrobial properties. It can inactivate pathogens on the hands and also does not need regulatory approval since it is considered a personal care product.

Many greenhouse workers now use nitrile gloves to minimize risk of rugose virus spread, but it could still adhere to gloves so it is critical to change them often. The hand rub has potential to provide longer protection and reduce overall spread by workers hands.

Ozone oxidizers

The third solution tested was an ozone treatment containing powerful oxidizers that can kill micro-organisms or inactivate viruses when applied to surfaces. There was a 98 per cent reduction in rugose virus after three minutes of contact with aqueous ozone. That is a shorter contact time than what is necessary for many commercially available disinfectants.

Work is still underway to determine the best and most critical uses for this product.

All three solutions, which can be used together or separately, may be adopted by the industry, notes Bennett. The next step is determining how they can be best commercialized. There is initial interest by growers, but trials are needed to validate that interest.

“We have some pretty unique techniques here that we haven’t seen anyone else using in the greenhouse industry — and they could help us with future issues too, not just the issues of today like COVID and rugose,” she says.

“They challenge the traditional way of addressing viral and bacterial issues, which is usually reactive, and move us into the proactive and preventative space. That’s where the cost savings are, in reducing disease transmission and keeping people and plants healthy.”

For the vegetable growers, the ultimate goal is to make the sector more resilient to pathogen threats to its workforce and its crops and keep growers competitive and productive.

According to Bennett, that will mean changing crop protection strategies from reactive to proactive and seeking solutions that are effective but don’t require lengthy regulatory approval processes.

This project was supported through the Greenhouse Competitiveness and Innovation Initiative, a cost-share program funded by the Ontario government and delivered by the Agricultural Adaptation Council on behalf of the Ontario Ministry of Agriculture, Food and Rural Affairs.

“The GCII funding was incredibly important and a really unique opportunity for us because the funding focused on plant health and COVID-19,” adds Bennett.

“It’s not often that you can access both and have benefits to both, and it makes it much easier to look for solutions knowing that funding is available to help.”