By Lukie Pieterse, Editor and Publisher of Potato News Today

As the global potato industry evolves to meet rising demand, sustainability goals, and consumer expectations, one critical threat continues to cast a long shadow across production systems worldwide: the growing risk of fungicide and insecticide resistance.

As the global potato industry evolves to meet rising demand, sustainability goals, and consumer expectations, one critical threat continues to cast a long shadow across production systems worldwide: the growing risk of fungicide and insecticide resistance.

For decades, chemical crop protection tools have been indispensable in the fight against devastating diseases such as late blight (Phytophthora infestans) and early blight (Alternaria spp.), as well as destructive insect pests including the Colorado potato beetle, wireworms, aphids, and leafhoppers. These pathogens and pests have the capacity to decimate yields, diminish tuber quality, and disrupt entire supply chains — making reliable protection strategies a cornerstone of modern potato farming.

But that foundation is now under increasing strain. In recent years, researchers and industry networks have documented alarming trends: reduced sensitivity or outright resistance to many key fungicides and insecticides is being reported with greater frequency across major production regions in North America, Europe, and beyond. Strains of late blight less sensitive to phenylamides and QoI fungicides are gaining ground. Early blight populations resistant to SDHIs are spreading. Colorado potato beetles are developing resistance to multiple classes of insecticides in areas where they were once controllable. And aphids — the vectors of costly viruses like PVY — are showing resistance to widely used pyrethroids and carbamates.

This is not a theoretical risk or a distant threat — it is a reality now being faced by growers in their fields. And it has profound implications for yield security, production costs, environmental stewardship, and the long-term sustainability of potato farming itself.

As Dr. Anne-Kristin Mahlein of the EuroBlight network observes: “Resistance is dynamic — it evolves rapidly if we do not manage it proactively. We must continuously adapt our practices if we want to preserve the tools that remain effective.”

In this in-depth feature for Potato News Today, we examine the current state of resistance in potato production, explore how it develops, highlight key regional hotspots, and share expert-driven strategies that growers and the industry can adopt to turn the tide.

The battle is far from over — but whether we win it depends on the choices made today.

The Escalating Challenge of Resistance

In potato production, few threats loom larger than diseases such as late blight (Phytophthora infestans) and early blight (Alternaria spp.), alongside a suite of economically damaging insect pests including aphids, Colorado potato beetles, wireworms, and leafhoppers.

For decades, chemical crop protection products have been indispensable allies in the fight to maintain yield and quality. However, the adaptive nature of these pathogens and pests is now putting unprecedented pressure on resistance management.

Around the world, concerning patterns are emerging:

• Late blight strains less sensitive to key fungicides such as phenylamides (including metalaxyl) and QoI (quinone outside inhibitor) fungicides have been detected in multiple European countries, North America, and even parts of South America.
• Early blight populations exhibiting resistance to SDHI fungicides are becoming increasingly widespread, particularly in fields where these products have been used for multiple consecutive seasons.
• Colorado potato beetle resistance to neonicotinoids, pyrethroids, and spinosyns has now been documented in nearly every major potato-producing region of North America, with particularly severe resistance hotspots in the US Great Lakes region and parts of Eastern Canada.
• Aphid resistance to pyrethroids and carbamates has been reported in Western Europe, Eastern Europe, and parts of the Pacific Northwest, raising new complications for managing virus transmission such as PVY.

These shifts are not isolated to one geography or pest — they are global, systemic, and accelerating.

How Did We Get Here?

Resistance is not a new phenomenon — it is a natural evolutionary process that occurs when pathogens or pests adapt to survive chemical controls. Yet in modern agriculture, several factors have made this process more rapid and widespread:

• Over-reliance on single modes of action: In many regions, growers have historically relied heavily on specific groups of fungicides or insecticides, such as strobilurins (QoIs) or neonicotinoids, applying them multiple times per season without sufficient rotation. This selection pressure drives resistance.
• Reduced availability of new active ingredients: The pipeline for new chemistries has slowed dramatically. Developing and registering new products is a costly, time-consuming process that faces increasingly stringent regulatory hurdles, particularly in Europe. This has led to fewer new options coming to market, leaving growers to depend on older tools.
• Limited rotation of protection strategies: Economic realities often lead to tighter crop rotations and repeated planting of potatoes in the same fields, which increases pathogen and pest carryover. In some cases, agronomic flexibility is limited, and cultural or biological controls are not fully integrated.
• Climate-driven shifts: Warmer temperatures and erratic weather patterns are extending the active season for pests and diseases. For instance, longer growing seasons or earlier springs can mean more generations of Colorado potato beetles or more favorable conditions for blight infection. This leads to increased use of crop protection products — and thus more resistance pressure.

The Broader Implications

The escalating problem of fungicide and insecticide resistance is not just an agronomic concern — it carries ripple effects across the entire potato value chain, from farm to consumer. If left unchecked, resistance can undermine not only production profitability but also food security, market stability, and public trust in modern agriculture.

At the farm level, growers face rising input costs as they are forced to apply more frequent sprays, increase dosage rates, or turn to more expensive chemistries to maintain control. In regions where resistance is already severe, some growers are forced to apply products prophylactically, further compounding costs and driving environmental risk.

As resistance spreads, yield and quality losses also become more likely. In cases where no effective chemical option remains, outbreaks of late blight, early blight, Colorado potato beetle, or aphid-borne viruses can devastate a crop — leading to contract penalties for processors, rejection of loads, or outright crop failure.

The environmental consequences of resistance must also be considered. When growers lose access to selective, modern products, there is a temptation — or in some cases, no alternative — to fall back on older, broader-spectrum chemistries. These may carry greater risks to beneficial insects, soil health, water quality, and non-target organisms, running counter to the industry’s long-term sustainability goals.

From a market perspective, resistance-driven outbreaks can trigger sudden disruptions in supply. For example, a late blight epidemic in a processing region could limit delivery volumes and force processors to seek tubers from further afield, disrupting logistical chains and inflating costs. Similarly, an unexpected spike in virus incidence could lead to seed shortages or downgraded seed quality for future seasons.

At the level of consumer perception, resistance can fuel broader concerns about pesticide use in food production. If resistance forces increased chemical use, or leads to media-visible crop failures, this may erode public trust — particularly in markets with strong demand for sustainably produced food.

Finally, there are regulatory implications. Policymakers are paying increasing attention to resistance trends, particularly in Europe, where legislative pressure to reduce pesticide use is strong. If resistance continues to escalate, it could trigger stricter regulatory responses or accelerate product withdrawals, further limiting growers’ options.

In short, the broader implications of resistance are systemic and profound:

• Higher costs of production
• Increased crop losses and supply disruptions
• Environmental trade-offs
• Market instability and logistical disruptions
• Erosion of consumer trust
• Heightened regulatory scrutiny

For the potato sector, addressing resistance is not just a technical challenge — it is a strategic imperative for ensuring the long-term viability and resilience of the entire industry.

Are We at a Tipping Point?

While many current fungicides and insecticides still provide effective control when used within a disciplined, integrated program, there is growing consensus among researchers and industry leaders that the potato sector is approaching a critical juncture in its battle against resistance.

On the surface, it may appear that growers still have tools available for managing late blight, early blight, Colorado potato beetle, and aphid vectors. But beneath that surface, the margin for error is narrowing — and the window of opportunity to preserve these tools is closing faster than many realize.

In certain hotspots in North America, entire classes of insecticides have already been rendered largely ineffective. As Dr. Neil Gudmestad warns: “Growers cannot assume the same tools will remain effective season after season — proactive resistance management is no longer optional.”

In Europe, fungicide resistance in late blight and early blight populations is forcing growers to rely increasingly on fewer remaining modes of action — a dangerous trajectory that risks creating new resistance bottlenecks.

Why is this a tipping point moment?

• Because the development pipeline for new chemistries is too slow to easily replace lost tools. It can take 10 to 15 years — and hundreds of millions of dollars — to bring a new product to market. Meanwhile, resistance can evolve in just a few seasons if stewardship falters.
• Because regulatory pressure is accelerating in key markets, particularly in the EU. If resistance drives misuse or overuse of products, it will feed into the policy cycle pushing for more stringent pesticide reductions and product withdrawals.
• Because climate change is exacerbating the risk landscape. Warmer winters, earlier springs, and longer growing seasons are giving pests and pathogens more generations per year — and creating more opportunities for resistance to emerge.
• Because the economic pressures on growers — from contract demands, input inflation, and sustainability targets — make it tempting to stick with familiar tools rather than adopt more complex integrated strategies.
• And because regional disparities in stewardship can create “leakage” effects — where poor resistance management in one area undermines control efforts across entire regions or countries.

In other words: even though many tools still work today, the current trajectory is unsustainable without a significant shift in how resistance is managed.

If the industry continues on its current path, it risks entering a vicious cycle: as resistance reduces efficacy, growers use products more intensively, accelerating further resistance — until critical tools are lost entirely. At that point, it becomes extremely difficult, if not impossible, to recover lost ground.

The tipping point is not theoretical — it is here. Whether the industry moves toward a virtuous cycle of proactive stewardship and innovation, or a downward spiral of reactive overuse, will depend on the actions taken today and in the coming seasons.

Strategies for Turning the Tide

Fortunately, there is a clear path forward — but it requires commitment from all levels of the industry:

• Integrated pest management (IPM): Growers should prioritize non-chemical tools where possible, including resistant varieties, improved irrigation and nutrition management, biological controls, and cultural practices that reduce pest and disease pressure.
• Rotation of modes of action: Rigorous adherence to FRAC (Fungicide Resistance Action Committee) and IRAC (Insecticide Resistance Action Committee) guidelines is essential. This means rotating between chemical groups, avoiding back-to-back applications of the same mode of action, and alternating products across seasons.
• Optimal application practices: Full label rates, precise timing based on disease forecasting or pest thresholds, and correct coverage are crucial to maintaining efficacy and avoiding sub-lethal exposure that fosters resistance.
• Monitoring and diagnostics: Regional networks such as EuroBlight, AphidWatch, and academic surveillance projects play a key role in tracking emerging resistance. Growers and advisors should engage with these resources and adapt programs based on the latest data.
• Support for innovation: The industry must continue advocating for investment in new solutions — not just new chemistries, but also biologicals, precision application technologies, and resistant cultivars.
• Regional collaboration: Resistance is not a farm-by-farm issue. Coordinated approaches across grower groups, cooperatives, and entire regions can reduce overall selection pressure and preserve the tools that remain effective.

The Role of the Potato Research Community

The global potato research community is playing an indispensable role in the industry’s response to the growing challenge of fungicide and insecticide resistance. Across North America, Europe, and other key potato-producing regions, public and private sector researchers are working across multiple fronts to develop new solutions, inform best practices, and equip growers with the knowledge they need to stay ahead of resistance trends.

1. Breeding for Durable Resistance

Perhaps the most powerful long-term weapon against resistance is the development of potato varieties with durable, stacked genetic resistance to key diseases and pests.

Breeders in both public programs and private companies are now advancing cultivars with multi-gene resistance to late blight, early blight, and even virus transmission by aphids. The integration of resistance genes sourced from wild Solanum species has opened new frontiers in breeding programs from the Netherlands to the UK, Germany, the US, and Canada.

Importantly, breeding efforts are shifting toward quantitative resistance — which is less likely to be overcome by pathogens — rather than reliance on single resistance (R) genes alone. This approach aims to provide more durable protection that can be combined with integrated crop protection programs.

2. Advancing Biological Solutions

Biological crop protection products — including microbial biopesticides, plant extracts, and RNAi-based insecticides — represent a promising frontier for reducing reliance on traditional chemistries.

Researchers are testing a wide range of biological agents for their ability to suppress late blight infection, inhibit spore germination, deter insect feeding, or disrupt pest reproduction. Several biologicals are now commercially available in Europe and North America, and more are advancing through regulatory pipelines.

Of particular interest are RNA interference (RNAi) technologies, which offer highly targeted modes of action against pests like Colorado potato beetle — with minimal non-target effects. Field trials in North America and Europe are yielding promising results.

3. Modeling and Forecasting Tools

Digital agriculture is becoming an increasingly valuable tool for resistance management. Researchers are developing advanced forecasting models that integrate weather data, pathogen life cycle modeling, and pest population dynamics to help growers optimize spray timing.

For example, EuroBlight’s late blight forecasting platforms and various university-led early blight and Colorado potato beetle models are helping growers reduce unnecessary applications — a critical step in slowing resistance development.

Similarly, AphidWatch and other virus-monitoring networks are improving aphid management by enabling more targeted control strategies.

4. Surveillance and Diagnostics

Resistance management is impossible without accurate, timely data on what’s happening in the field. Research networks are conducting ongoing resistance monitoring to track shifts in pathogen and pest populations.

• EuroBlight publishes annual reports on fungicide sensitivity trends in European late blight populations.
• US and Canadian researchers are conducting systematic screening for Colorado potato beetle resistance to neonicotinoids and other classes.
• Aphid resistance is being mapped across European seed production zones — informing virus management programs.

Such surveillance allows researchers and extension advisors to issue timely alerts and guide growers in adjusting their crop protection programs accordingly.

5. Extension, Education, and Stewardship

Finally, the research community plays a vital role in educating growers, advisors, and industry leaders about best practices in resistance management.

Extension specialists such as Dr. Andy Robinson (North Dakota State University / University of Minnesota), Dr. Steven B. Johnson (University of Maine Cooperative Extension), and Dr. Jeff Miller (Miller Research, Idaho), among others, are leading the charge in translating research into actionable guidance for the industry.

Through workshops, webinars, publications, and field days, these experts are helping growers adopt:

• More diversified IPM programs
• Rigorous MOA rotation
• Precision application strategies
• Monitoring-based decision-making

In Summary

The potato research community is not standing still — it is delivering an expanding toolkit of solutions:

• Breeding for stacked, durable resistance
• Biologicals to complement or replace chemical options
• Forecasting models to optimize application decisions
• Monitoring to detect and track resistance trends
• Education to foster a culture of proactive stewardship

Yet for these efforts to succeed, they must be fully embraced by the industry. Collaboration between researchers, growers, crop consultants, processors, and policymakers is essential to translating scientific advances into field-level impact.

A Call to Action

As global potato production moves into an era defined by sustainability, climate resilience, and supply chain security, the industry can no longer afford to treat fungicide and insecticide resistance as a secondary issue. The evidence is clear: resistance is evolving, spreading, and threatening the tools that farmers depend upon to protect yields and quality.

Whether the battle is won or lost will hinge on how swiftly and decisively growers, agronomists, researchers, and industry leaders embrace a culture of resistance stewardship.

The battle against fungicide and insecticide resistance is far from lost — but it cannot be won through business as usual.

For the global potato industry, this is a moment of truth: will we collectively embrace the best science and stewardship practices available, or will we risk sliding into an era where our crop protection arsenal is fatally compromised?

The tools we have today represent decades of innovation and investment. Preserving them — while accelerating the development of next-generation solutions — is one of the most pressing challenges facing modern potato production.

For growers, agronomists, researchers, and industry leaders, the message is clear: resistance is everyone’s responsibility. The time to act is now — because, as many experts remind us, resistance is dynamic — and so too must be our response.

Key Takeaways: Managing Resistance in Potato Production

• Resistance is real and accelerating: Global hotspots of fungicide and insecticide resistance are being documented in key potato-growing regions.
• Multiple threats in play: Late blight, early blight, Colorado potato beetle, and aphid resistance are among the most pressing concerns.
• How it happens: Over-reliance on single modes of action, limited chemical rotation, climate-driven shifts, and declining innovation pipelines all contribute to resistance development.
• Broader impacts: Increased input costs, crop loss risk, market disruptions, and environmental concerns make resistance a critical industry-wide issue.
• Action needed now: Integrated pest management, rigorous MOA rotation, precision application, ongoing monitoring, and support for innovation are key to preserving effective tools.
• Stewardship is everyone’s responsibility: Growers, advisors, researchers, suppliers, and policy-makers must collaborate to build a culture of proactive resistance management.

Author: Lukie Pieterse, Editor and Publisher of Potato News Today
Cover image: Credit Joaquin from Pixabay