Rising temperatures and market shocks are rewriting economics of crop protection

Rising pest pressure, climate instability, and volatile crop markets are forcing a rethink of one of agriculture's most established economic rules: when to spray and when to wait. A new review states that the traditional formulas used to decide when pest control becomes economically justified are no longer sufficient in a warming, digitized, and globally interconnected food system. The study warns that without adaptive, climate-aware thresholds, farmers risk either overspending on unnecessary interventions or delaying action until yield losses are irreversible.

Published in the journal Agriculture, the study titled Conceptualisation of Economic Injury Level and Economic Threshold: Agricultural Management, Food Security, Climate Factors, and Value Chain re-examines two cornerstone concepts of integrated pest management, the Economic Injury Level (EIL) and the Economic Threshold (ET), within the broader realities of climate change, food security risk, supply chain vulnerability, and artificial intelligence-driven decision systems.

Climate and market volatility redefine pest control economics

For decades, the Economic Injury Level has been defined as the lowest pest population density at which the cost of control equals the value of the crop loss prevented. The Economic Threshold, set below that point, signals when action should be taken to stop pests from reaching economically damaging levels. In simple terms, EIL identifies the break-even point, while ET provides the practical trigger for intervention.

The author traces the origins of these concepts to mid-twentieth-century efforts to rationalize pesticide use and embed economic reasoning into pest management. The original formula linked control cost, crop value, damage per unit injury, injury per pest, and control effectiveness. The logic was clear: treat only when the expected loss exceeds the cost of action.

But the review argues that the once-stable relationships underpinning these thresholds have fractured under modern pressures.

One major disruption is climate change. Rising temperatures accelerate insect metabolism and shorten generation cycles, allowing pest populations to reach damaging densities faster than historical models predicted. Warmer and more humid conditions increase feeding rates, intensify crop injury, and expand pest ranges into new regions. In storage facilities, warming microclimates are boosting post-harvest pest reproduction, raising contamination risks and threatening grain quality further along the value chain.

These biological changes compress the gap between ET and EIL. Farmers now have less time to respond before pest populations cross the economic damage threshold. Static thresholds derived under past climate conditions are increasingly unreliable.

At the same time, market volatility is reshaping the economic side of the equation. Crop prices fluctuate sharply due to global supply shocks, geopolitical tensions, and extreme weather. When comThe authorty prices rise, the economic value of each unit of yield increases, effectively lowering the EIL and justifying earlier intervention. When prices fall, or when pesticide and fuel costs surge, the EIL rises, making treatment less profitable.

Both control cost and crop value sit at the core of the EIL formula. A doubling of spray cost can significantly raise the pest density required to justify treatment. Conversely, higher maize or horticultural prices reduce the pest density at which intervention becomes economically sound.

Ignoring these economic signals risks misaligned decisions. Early spraying under low crop prices can erode margins. Delayed action under high crop prices can magnify losses. The author concludes that EIL and ET must be recalibrated dynamically rather than applied as fixed numbers.

Natural enemies, crop stages, and the push for precision IPM

The review highlights ecological complexity often overlooked in simplified threshold systems. Pest density alone does not determine economic risk. The presence of natural enemies, such as predators and parasitoids, can significantly suppress pest growth and delay the point at which economic damage occurs.

Strong biological control can effectively raise the ET by reducing expected pest population growth between scouting intervals. Conversely, pesticide overuse can disrupt beneficial organisms, triggering secondary pest outbreaks and reinforcing a cycle of dependency on chemical control. The study stresses that threshold decisions must incorporate predator-prey dynamics to avoid ecological backlash.

Crop stage also plays a decisive role. Early vegetative stages in maize and other crops can be highly sensitive to pest injury. Damage per pest is not constant across the season. During flowering or grain filling, injury may translate into greater yield loss per pest equivalent. This means the damage coefficient in the EIL formula shifts over time, lowering the economic threshold during vulnerable growth stages.

The review draws on maize case studies involving fall armyworm and stem borers to illustrate stage-specific thresholds. Early infestations may require rapid response due to exponential pest growth and high vulnerability, while late-stage infestations must weigh diminishing yield return against treatment cost.

The traditional break-even formula remains valid in principle, but its parameters are dynamic. Pest growth rate, crop sensitivity, control efficacy, natural enemy pressure, and market price must all be monitored in real time.

This is where precision agriculture enters the picture. The study details how remote sensing, smart traps, environmental sensors, and artificial intelligence are transforming integrated pest management. Weather-driven forecasting models can predict pest emergence based on temperature and rainfall anomalies. IoT networks track microclimate conditions in fields and storage units. AI models analyze pest pressure trends and estimate when populations are likely to cross economic thresholds.

Rather than relying on fixed threshold tables, farmers can use predictive systems that integrate climate data, pest surveillance, and crop condition indicators. These tools allow ET to function as an adaptive, context-sensitive trigger rather than a static guideline.

However, the review cautions that digital systems must remain aligned with biological and economic fundamentals. Early-warning frameworks that prioritize risk detection may inadvertently lower thresholds excessively, triggering premature intervention and undermining the principle that some pest injury is tolerable. Without integration of natural enemy indicators and economic calibration, predictive systems could reintroduce the over-spraying behavior that EIL was designed to prevent.

Food security and the value chain at risk

The study expands the EIL and ET discussion beyond field-level profitability to global food security. Pest damage is estimated to account for a large share of global crop losses, particularly in regions such as sub-Saharan Africa where smallholder farming dominates. In such contexts, timely threshold-based intervention can directly influence food availability, household income, and supply chain stability.

By preventing pest populations from exceeding economically damaging levels, EIL and ET frameworks reduce avoidable yield loss and improve farm profitability. The review cites evidence linking pest alert systems and threshold-guided decision tools to higher adoption of integrated pest management practices, as well as measurable gains in yield and income.

Food access is closely tied to farm income. Over-application of pesticides increases production costs and reduces margins, while delayed intervention can slash output. Rational, threshold-based pest management supports stable earnings and strengthens purchasing power in rural communities.

Food utilization and safety are also implicated. Excessive or mistimed pesticide use can leave residues on produce and disrupt beneficial ecological services. In post-harvest systems, rising temperatures accelerate pest growth in storage facilities, increasing contamination and quality degradation. Climate-aware ET systems applied across production, storage, and distribution stages can protect both yield and food safety.

EIL and ET tools aren't only for individual farm management but for supply chain resilience. Pest outbreaks at the production stage ripple through processing, distribution, and retail, affecting price stability and consumer access. Adaptive thresholds that account for climate stress, invasive species expansion, and market volatility can help stabilize output across entire regions.

The author also examines the integration of predictive risk frameworks with classical thresholds. Continuous monitoring, climate modeling, and digital early-warning systems offer significant advantages in forecasting outbreaks and improving response timing. However, the study warns that such systems are data-intensive and may be impractical in resource-limited settings without institutional support. Simplified, farmer-friendly interfaces and regionally coordinated surveillance are identified as key to successful adoption.