Crop pests: why the 2026 season highlights the importance of enhanced monitoring

High moth populations, early flights, highly variable crop damage and development cycles disrupted by weather conditions: the 2026 growing season has once again demonstrated the complexity of managing insect pests. In this context, monitoring pest populations and anticipating their development are becoming essential for adapting crop protection strategies.

2026: high moth populations, but highly variable crop damage

The 2026 season was marked by high populations of several moth species that are major agricultural pests, particularly Helicoverpa armigera (cotton bollworm) and Lobesia botrana (European grapevine moth). However, this intense adult activity did not systematically result in significant caterpillar infestations in the fields. This situation can largely be explained by the exceptional summer weather conditions.

According to Météo-France, summer 2026 was the hottest recorded in France since 1900, with average temperatures 3.6°C above seasonal norms. It was also marked by a rainfall deficit of nearly 40% and historically severe soil drought. These extreme conditions had a major impact on insect pest development, with consequences sometimes varying considerably from one field to another.

While high temperatures can accelerate the development of many insects, extreme heat combined with low humidity can also cause significant mortality, particularly at the egg stage. As a result, despite sometimes substantial moth flights, some eggs failed to hatch, locally limiting crop damage.

Conversely, in fields with more humid conditions, or where eggs were laid in protected parts of the plants rather than on leaf surfaces, survival rates may have been higher. Caterpillars were then able to continue developing, sometimes causing significant crop damage.

Weather conditions make pest monitoring more challenging

The 2026 season clearly illustrates the influence of climate on insect pest population dynamics. Temperature plays a key role in insect development rates. Under favourable conditions, rising temperatures can shorten the duration of different biological stages and accelerate the succession of generations.

This year, this acceleration was particularly reflected in earlier-than-usual flights of certain pest species. For species such as the European grapevine moth (Lobesia botrana) and Cryptoblabes gnidiella (honeydew moth), some flights were observed several weeks earlier than usual. These shifts in biological timing make monitoring even more important: pest activity periods no longer necessarily follow historical patterns, and monitoring practices must adapt accordingly.

However, when temperatures become excessively high or very dry conditions persist, insect development can be disrupted, with particularly significant effects on the survival of eggs and young larvae. These factors explain why high adult populations do not necessarily lead to high larval pressure, and why two neighbouring fields may experience very different levels of infestation.

Under these conditions, monitoring must cover several stages of the pest life cycle:

• Adults (moths): to identify flight periods, including unusually early ones, and anticipate potential egg-laying.

• Eggs: to assess reproductive activity and identify periods of increased risk.

• Larvae (caterpillars): to confirm the actual presence of the pest, assess infestation severity and determine whether intervention is necessary.

Combining flight monitoring with field observations is essential for effective and well-informed crop protection decisions.

Anticipating risk periods through pest development modelling

To support farmers and agricultural advisers in this approach, Cap 2020 has introduced a new pest life cycle modelling feature for selected insect pests during the 2026 season, directly integrated into the CapTrap platform.

Using pest population monitoring data and temperature conditions, this feature estimates when the different developmental stages of a pest are likely to occur: eggs, larvae, pupae and the emergence of new adults. The aim is to move beyond simply monitoring moth flights towards better anticipation of periods when crops may be at risk.

More specifically, this modelling feature makes it possible to:

• Anticipate egg-laying and hatching periods, based on observed moth flights.

• Predict periods of larval presence, as caterpillars are responsible for crop damage in many moth species.

• Target field inspections more effectively, focusing monitoring efforts on the most relevant periods.

• Optimise the timing of interventions, when field observations confirm a level of risk that justifies treatment.

• Anticipate subsequent generations, ensuring appropriate monitoring throughout the growing season.

It is important to note, however, that these models describe the potential development of pests based on temperature conditions. They do not account for mortality that may occur under unfavourable weather conditions, such as drought or extreme heat.

This is precisely what the 2026 season demonstrated: modelling is a valuable tool for anticipating risk periods, but it must be combined with field observations to assess actual pest pressure.

CapTrap: automating pest monitoring for better crop protection

As pest monitoring needs to become increasingly accurate and responsive, connected trapping solutions offer a practical response to the needs of agricultural professionals.

Developed by Cap 2020, the CapTrap range of connected insect traps enables automated monitoring of pest populations directly in the field.

With different trap configurations adapted to target species (funnel, delta, cage, vertical traps, etc.), CapTrap devices automatically detect and count insects before transmitting the results to a dedicated web platform. Users can therefore access regularly updated information on pest population trends without having to systematically visit each trap for manual inspections.

The CapTrap service offers several key benefits:

• Remote pest population monitoring, with automated and regularly updated insect counts.

• Early detection of initial flights and activity peaks, helping identify periods requiring increased vigilance, even when flights occur earlier than expected.

• Reduced travel and time spent on manual trap inspections, particularly valuable for extensive monitoring networks.

• Centralised data management and analysis, with graphs that make it easier to understand pest population dynamics.

• Enhanced decision support, through the integration of development models for selected pest species.

By combining trapping data with biological development models, CapTrap helps users better anticipate critical periods and organise field observations more efficiently. The aim is not to replace the expertise of farmers and agricultural advisers, but to provide them with reliable and relevant information to support their decisions.

Towards increasingly sustainable and targeted crop protection

In a context of growing climate variability and a decreasing range of available plant protection products, access to accurate and up-to-date information on pest populations is becoming a major challenge. This is where combining automated monitoring, pest development modelling and field observations provides real value.

Through its CapTrap service, Cap 2020 supports this transition by offering tools designed to simplify pest monitoring, anticipate risks and optimise crop protection strategies.

Because a better understanding of pest populations and their development dynamics ultimately makes it possible to intervene at the right time, when necessary, to protect crops effectively while promoting a more targeted and sustainable approach to pest management.

Would you like to learn more about CapTrap connected insect traps and the available modelling features? Contact us!