Tackling the Problem of Fungicide Resistance
Fungicides are a crucial line of defense against fungal infections in crops. But what can we do when fungi evolve to resist these methods of control?
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Fungicides are an integral part of the food and agriculture industry, playing a key role in the prevention of major crop losses due to fungal blight and infection. However, after decades of use, fungal species can evolve to become genetically opposed to these fungicides, rendering them ineffective.
In the face of a growing global population and fears over food insecurity, finding alternate fungicides with different methods of action – ones that fungal species will struggle to adapt to – has become a major research priority if crop losses are to be minimized.
To learn more about fungicide resistance and the novel fungicides being developed to tackle this looming problem, Technology Networks spoke with Chris Wightman, founder and CEO of VM Agritech. Under Wightman’s guidance, VM Agritech has developed and is in the process of launching a new broad-spectrum fungicide specifically designed to minimize the development of fungal resistance.
Alexander Beadle (AB): Can you give us an overview of the current situation regarding fungicide resistance and the danger it presents?
Chris Wightman (CW): Fungicide resistance is probably the biggest unacknowledged global agricultural problem. The first issue is that fungi, like all pathogens, have an amazing ability to adapt to our chemical attempts to kill them. Because there have been no real breakthroughs in fungicide chemistry in the last 30 years, fungi have adapted to what was once the amazing killing power of azoles and strobilurins. The same thing that is happening with antibiotics, humans and bacteria is happening with fungicides, crops and fungi. Overuse has led to resistance and now our defenses are being rendered more and more ineffective every year as Mother Nature adapts.
When a resistant strain of fungus infects a field or an orchard, it can affect yield by up to 70%. Tar spot on corn, white mold on soybeans, downy mildew on grapes, coffee rust – the list goes on and on. Every crop has a pathogen capable of wiping out a farmer’s crop. So, for farmers globally, current fungicides used are less of a financial insurance policy and more of a gamble, as fungal strains are becoming more resistant, frequent and intense.
On average, global crop losses caused by fungal pathogens are around 20% per year. Without the use of fungicides, it is estimated the world would lose 30–40% of its crop production. These figures are only set to increase, with research indicating that rising global temperatures will worsen the danger posed to crops by fungi as they move toward the poles.
Insufficient food supply is already a serious issue and resistance plays a significant part in this. According to a 2021 World Health Organization report, approximately 9 million people die every year from starvation, 800 million people face hunger and more than 2.4 billion people are considered to not have adequate access to food. Furthermore, it is estimated that the combination of population growth and changing diets will mean that 70% more food will need to be produced by 2050 – only 27 years away.
A solution to resistance also becomes part of the solution to food security and supply, without adding additional farmland. If there is a solution to resistance, we might be able to stop cutting down rainforests, to meet the Glasgow declaration made at COP26 which plays critical a role in reducing global warming.
In addition to their declining efficacy, many of the existing fungicides in the market have been proven to have significant negative side effects related to human health. There is also evidence of the agricultural use of azoles being a factor in the crossover resistance to fungal infections in humans; azoles are a primary anti-fungal prescription for humans. Fungal resistance is now a major cause of human deaths.
The wider economic impact of fungicidal resistance is huge. For wheat, rice, corn and soy, a 10% crop loss exceeds $100 billion in annual crop value. We need to produce more food and we need to do it without further destruction of the world’s biodiversity. The answer is not to expand farms through deforestation, but to maximize crop yields. One of the major answers to this lies with new, more effective fungicides.
AB: Tell us about Curezin®. What makes it different from other fungicides?
CW: Curezin, VM Agritech’s first product, is a broad-spectrum, copper-and-zinc-based fungicide. It’s many times more powerful than the directly comparable fungicides, and its efficacy and mode of action have been proven independently by field trials at Cornell University and other leading academic institutions, in addition to several commercial field trials.
Curezin demonstrates a kill rate as effective as azoles and strobilurins – the most widely used fungicide chemistries globally – but without the susceptibility to fungicidal resistance that comes with these. This is because fungal pathogens are unable to develop resistance to the way that copper works. However, traditional copper formulations are not sufficiently effective to be used widely. Curezin, because of its unique, patented formulation delivers both efficacy and zero resistance. And it only uses a fraction of the copper that traditional copper chemistries use, making it much better for the environment.
Curezin, when approved, will be the only product on the market that has these characteristics and benefits. The product therefore has the potential to disrupt this huge global market very quickly.
AB: Some copper-based fungicides have previously faced criticism, largely for environmental reasons, as they introduce some amount of heavy metal into the soil. Can copper-based fungicides still be used responsibly?
CW: Yes, they can. Once approved, Curezin will be an example of this: a responsible, copper-based fungicide that can be widely used by farmers and growers.
Copper is one of the oldest fungicidal ingredients used in agriculture. However, current copper chemistries at suggested levels of application accumulate in the soil at levels that can be highly toxic.
Curezin has been proven to be 4–50 times more effective than existing copper chemistries, depending on the particular pathogen, while only using a fractional amount of copper in soluble form (less than 20%). It is the addition of zinc which, in a unique soluble form that turbo-charges the efficacy, enables such a small amount of copper to be used.
The concerns about copper soil toxicity in fungicides are legitimate, but Curezin negates this issue, utilizing a small amount of copper to provide a highly effective fungicide while creating a negligible risk of a toxic metal build-up in the soil.
AB: VM Agritech partnered with Cornell to test and develop Curezin. Can you tell us a little more about this process?
CW: While the original in vitro analysis was performed in the UK, when we knew that Curezin had the potential to be a broad-spectrum replacement for existing chemistries, we knew we had to launch in the US. The agricultural market is many times bigger than the UK and is the place that we knew we needed to begin commercialization.
We began working with the College of Agriculture and Life Sciences (CALS) at Cornell in 2021 to conduct our wide-ranging field trials. Researchers at Cornell, experts in plant pathology and plant–microbe biology, started with apples and beetroots, demonstrating that Curezin was as effective as azoles and strobilurins. That work has continued through 2022 into 2023, covering all major crops in addition to working with other major research universities such as Purdue, Penn State, Wisconsin and Idaho on row crops and the University of Wageningen in Holland, for bananas.
Our collaboration with Cornell has moved beyond just testing. We have re-domesticated the company to the USA in 2022 and are now based next to the CALS Research Station in Geneva, New York. We plan to build a manufacturing plant at the Cornell Agriculture and Food Technology Park once we have regulatory approval.
Due to the successful collaborative effort on Curezin, VM Agritech is now working on three additional testing programs with Cornell including a sporicidal application for crops in addition to applications for our IP in human and veterinary health.
Strong links between business and academia can be highly valuable in commercializing and bringing new innovations to market. We have been extremely fortunate to have been able to partner with Cornell throughout the process in the US.
AB: Are there any available project updates on when Curezin might become available, or on any further rounds of testing?
CW: Further official field trial results will be available in October 2023. We also have commercial field trial programs this season across a range of specialty and row crops with universities, farmers and agricultural product retailers.
We are currently waiting for Environmental Protection Agency (EPA) regulatory approval in the USA and will have a product ready for the 2024 North American growing season. Once approved, we will take the product to market in the USA and will begin the process of regulatory approval in the rest of the world. Our core Curezin patent (for formulation and use) has already been granted in 56 countries, including the USA, Canada, China and the European Patent Area.
Ultimately, we want Curezin to be available everywhere. Fungicide resistance is a global challenge, and the solutions must be available to everyone. Our global food supply depends on it.
Chris Wightman was speaking to Alexander Beadle, Science Writer and Editor for Technology Networks.