Climate & Agriculture: Leafhopper Pests Surge in Strawberry Fields

He looks pretty innocent, doesn't he.

Shifting Weather Patterns Create a Perfect World for Pests

From raging wildfires and floods to stifling heatwaves, it appears that "extreme weather events are increasing," reports NASA Science.

One environmental phenomenon that often flies under the radar is the rise of pest populations due to warmer weather, and what that means for global agricultural and food security. Of course, it's an incredibly complex problem that's ripe for further research.

A study out of Université Laval has revealed how leafhoppers — small, sap-sucking pests that are notorious for spreading diseases — are becoming markers of environmental change.

Core Findings: A Whole New World for Biodiversity

The study, published in Cell Reports Sustainability, explores how rising temperatures are reshaping biodiversity and, specifically, the behavior of leafhoppers in strawberry fields.

Those changes could undermine current pest management strategies and create challenges in maintaining crop health due to increased disease.

Here's what they found:

• Increased Populations: Researchers observed a marked increase in both migratory and non-migratory leafhopper populations across eastern Canadian strawberry fields. This surge was closely tied to warmer conditions that improved the insects' reproduction rates.

• Spread of Diseases: As populations increased, there was an uptick in the diseases leafhoppers carry and transmit. Specifically, phytoplasma disease doubled in strawberries over the last decade, exacerbated by temperature shifts.

The researchers also note that leafhoppers may be becoming more resistant to traditional insecticides, which is often driven by genetic adaptations fostered by continual exposure to these chemicals under changing climatic conditions.

"Our research provides evidence that leafhoppers are sensitive to the effects of climate change, making them ideal markers to research the effect of climate change on agriculture."

“Canadian agricultural pest advisories have doubled in the last decade, reflecting rising climate risks.”

— Government of Canada

Research Implications: Retooling Management Strategies

Given the state of environmental uncertainty across the globe, leaning on historical data to develop agricultural strategies isn't sufficient.

In Canada, for instance, temperatures have risen twice as fast as the global average. Below, you can see the chart indicates how much the temperature for a given year departs from the "normal" (based on baseline average temperature values from 1961 to 1990).

While leafhoppers are a significant concern for individual farms, they can now serve as critical climate-change markers. Monitoring changes in their behaviour can inform more sustainable agricultural practices, which are essential for the future of food security.

The Laval research also supports previous findings that adaptive, integrated pest management strategies using real-time data and predictive modeling will be needed to combat pest invasions.

From crop rotation to the development of pest-resistant crop varieties, integrated management strategies are becoming all the more urgent.

"In the coming years, the expected warmer climate will have a serious impact on insect pest distribution and disease incidence, posing a risk to food security."

Global Perspectives on Climate Change and Agriculture

Shifting weather patterns and global temperatures are believed be altering biodiversity, including the behaviours of many pest species. As pests move into new areas, they can bring diseases with them that ravage plants and reduce crop yields:

• 20% to 40% of global crop production is lost to pests annually

• Invasive insects cost the global economy ~$70 billion, while plant diseases costs ~$220 billion (FAO)

For example, warmer winters and extended growing seasons increase the activity of pests like the mountain pine beetle in North America and locust swarms in East Africa:

• The mountain pine beetle expanded its range northwards by hundreds of kilometers in Canada (Natural Resources Canada, 2023)

• The 2019-2020 locust swarms in East Africa (driven by unusual rainfall and warm conditions) were the worst in 70 years in Kenya and 25 years in Ethiopia and Somalia, threatening food security for over 20 million people (FAO, 2020)

Countries that depend heavily on agriculture for their economy and food supply, particularly in the Global South, are especially vulnerable and less resilient to agricultural shocks. The result? Livelihoods are threatened, risk of food scarcity increases, and food prices rise. Global supply chains are then disrupted, leading to market instability.

With more pests and disease comes an increased use of traditional chemical pest management. As chemical management increases, its effectiveness diminishes, as pests often evolve resistance to chemical insecticides and adapt to new environmental conditions.

• Pesticide use has increased by nearly 50% globally since 1990

• Pest resistance to insecticides is rising, with over 600 pest species now confirmed resistant to at least one type of chemical pesticide (Insecticide Resistance Action Committee, 2023)

This challenge is, unfortunately, compounded by the global nature of agricultural supply chains. Pests are easily transported across borders in shipments of agricultural goods.

“The escalation of pest invasions, a consequence of global warming, threatens food security in the typically cold northern hemisphere and exacerbates agriculture's impact on climate change by increasing pesticide usage.”

Future in Focus: Collaborative Tracking

What's increasingly clear is that international cooperation will be crucial, as shifting weather patterns and pests extend beyond borders, impacting us all.

By expanding our understanding of localized phenomena like leafhopper proliferation in strawberry fields — and shining a light on lesser explored areas environmental impact — researchers can help build a broader global strategy for agricultural resilience and food security.

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