The trick is to start small. Really small – at the tiniest droplets of crop spray, says Kripa Varanasi, professor of mechanical engineering at the Massachusetts Institute of Technology. One of his specialties is understanding how solid and liquid surfaces interact. He wondered whether containers designed to allow every last drop of liquid out could reduce pesticide pollution and improve the safety of workers treating crop fields. 

If you’ve ever lamented the last little bit of ketchup in the bottle that just won’t squeeze out, you’ll understand the challenge Varanasi faced. Bottles like these were exactly where he made his start. 

On regular solid surfaces, liquids spread out. This is bad news if you're trying to get a liquid out of a bottle because the liquids spreading over solids like to stay put. But by introducing a coating liquid onto the container wall – which on a microscopic level is rough and bumpy – the surface becomes a lot more slippery and smooth, helping to ease the liquid out. 

After testing this coating technology on ketchup, mayonnaise, honey and other sticky foods, they started thinking about the life cycle of agrochemicals – from manufacturing to packaging, dosing, delivery and disposal, recognising an opportunity to improve dosing and reduce waste.

Agrochemicals are often shipped in plastic containers as concentrates that gets diluted at the farm. When their contents have been poured out, there’s material stuck inside – like that pesky ketchup. That waste becomes a packaging disposal problem, because the leftovers are toxic. 

Another tweak to the materials used to deliver agrichemical products may drastically increase the efficiency of a pesticide spray. Farmers “basically douse [their] crops, but only 2-5% of what is sprayed actually sticks to the plant”, Varasani says. That got him thinking about how chemistry might help pesticide stay on target. 

“The majority of plants tend to be hydrophobic,” he says, meaning that water-based compounds tend to run off their waxy leaves. Past work has tested using surfactants – chemical additives that allow products to spread – to counter the waxiness of plants' leaves. But their success with pesticides has been limited. 

So Varasani has been tinkering with separating solutions into two components. One has an additive with a positive charge and one an additive with a negative charge. When they are sprayed onto the leaf, they attract the water-based pesticide solution, helping droplets stick to the otherwise water-repelling leaf. The additives, which are biodegradeable, could reduce pesticide volumes used by some 90%, Varanasi says, reducing both farmers' costs and harmful excess run-off.

“Pesticides represent a huge operational cost of running a farm, sometimes 50% of their operations,” says Varasani. So far, farmers appear interested, and Varanasi has trialled the technology at an orange grove in Florida, a vineyard in Italy, and a farm near his laboratory in Massachusetts.

Of course, it might not help everyone. Some farmers prefer not to use pesticides at all, says Hannah Wittman, academic director at the Centre for Sustainable Food Systems at the University of British Columbia. They are committed to other ways to keep their crops healthy while benefitting the environment. 

“They want to use diversified production strategies, integrated pest management, and grow food to be sold locally, not into a commodity market,” she says. “So they maybe can afford to let some of the pests live.” 

Alexa Alexander Trusiak, an ecotoxicologist with Environment and Climate Change Canada and the University of New Brunswick in Fredericton, is intrigued by possible applications of  waste-reducing technologies like those being developed by Varasani. But as someone studying the ecological impacts of multiple stressors, she urges caution. “We simply don't know yet if or how some of the most cutting-edge additives being developed will persist in the environment,” she says. 

As well as reducing the need for conventional sprays to kill pests, there are other ways to help protect plants from ill health. One approach makes use of an extraordinarily precise and well-adapted system that can deliver a substance exactly where it is needed – living bees. 

Bees do not only help plants grow and reproduce through their work as pollinators, but also transport communities of microbes around with them too. It has led some scientists to wonder if bees can be recruited to deliver beneficial fungi that protect plants, reducing the need for pesticides. 

Similar to humans harnessing beneficial fungi to produce antibiotic drugs like penicillin, beneficial fungi can boost plant health too. But how to get beneficial fungi onto plants efficiently, avoiding unnecessary waste, has been a puzzle.

That brings us back to bees, evolutionarily fine-tuned to focus on flowers, a plant part that pests often target too. Bee vectoring – getting bees to deliver beneficial organisms – is a bit like hopping on a bus heading for your desired destination. 

“Pollinators are already going around to the different flowers,” says Roselyne Labbé, an expert in greenhouse entomology with Agriculture and Agri-Food Canada in Harrow, Ontario. Bee vectoring minimises the dose needed, delivering it on target and distributing it evenly.

One tiny hero being carried by the bees is Clonostrachys rosea, a naturally occurring fungus discovered by John Sutton, a plant pathologist now retired from the University of Guelph, Ontario. Over his career, Sutton isolated over 1,400 different strains of this fungus found on farms. He found one strain particularly good at fighting plant disease. Inoculated with this fungus at the right time, it can stop pesky grey mould from growing on strawberries, for example. 

“Now we’re testing seven other microbes,” says Ashish Malik, president and chief executive of Bee Vectoring Technologies (BVT) International, which has commercialised this approach. So far BVT has used bee vectoring for blueberries, strawberries, tomatoes, sunflowers and almonds.

But how do you get a bee to carry the right fungus for you? Inside bee hives, a box of inoculant-dosed powder is placed so that the bees have to walk through it to exit to the outdoors. Dipping their legs and hairy bodies in the inoculant, the bees then carry their powdery packages to crops. 

Given widespread concern about the decline of natural pollinators, what about the possible ecological impacts of bee vectoring? To minimise the risk of accidentally introducing non-native species, BVT employs commercially reared bumblebees native to the place where it is used. “There’s always the possibility of some escape,” says Labbé. “But in general, the impact on natural pollinators is pretty minimal.”

Bee vectoring is also a very efficient way to deliver chemical agents, unlike traditional crop spraying where much of the control agent misses the mark, says Malik. So the hope is that bee vectoring will be less wasteful and could reduce or perhaps even replace pesticide use. 

Greenhouse gas emissions. Pesticide pollution. Unsustainable water use. Waste. Can we create a food system that supports both human and environmental health? Experts from many corners of research and innovation say “yes”, but it will require a rethink of what foods can be grown where, when and for how long.

Tammara Soma, professor of food system planning at Simon Fraser University in Burnaby, Canada, suggests that focusing exclusively on the tools, gadgets and technology of agriculture is a distraction. Supporting empowered, knowledgeable producers and consumers creates a more robust and genuinely sustainable system, she says. 

“High-tech is not very accessible to many people,” says Soma. Much of it is based on internet technology, and with that comes glitches, hacking and outages. “So you add another layer of vulnerability that shapes how we might be able to access food and how food is grown.” 

Technology is no panacea. But in reshaping the future of food, it’s one tool that, used carefully and made widely accessible, can contribute to a sustainable system that cares for both planet and people. 

Image credits: Getty Images, TwoFour

Graphics sources: Food and Agriculture Organization of the United Nations, International Society for Plant Pathology

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This article is part of a new multimedia series, Follow the Food by BBC Future and BBC World News. Follow the Food investigates how agriculture is responding to the profound challenges of climate change, environmental degradation and a rapidly growing global population.

Our food supply chains are increasingly globalised, with crops grown on one continent to be consumed on another. The challenges to farming also span the world.

Follow the Food traces emerging answers to these problems – both high-tech and low-tech, local and global – from farmers, growers and researchers across six continents.