Semiochemicals in Agricultural Entomology: A Critical Synthesis of Pest Monitoring, Mass Trapping and Integrated Pest Management

Abstract

Semiochemicals occupy a distinctive position in agricultural entomology because they can convert species- and context-specific chemical communication into tools for surveillance, behavioural manipulation and population suppression. This critical narrative review evaluates the evidence for semiochemical use in pest monitoring, mass trapping, attract-and-kill, mating disruption and integrated pest management, with particular attention to the transition from chemical discovery to reliable field performance. The literature was selected from agricultural, biological and multidisciplinary scholarly sources for the period 1 January 1990 to 19 June 2026, while retaining seminal studies needed to interpret current practice. The evidence is strongest for sex-pheromone monitoring and for mating disruption in well-characterised lepidopteran systems. Monitoring benefits from high sensitivity and taxonomic selectivity, but trap catch is not a direct measure of population density or crop injury unless lure performance, trap design, crop phenology, weather and management context are calibrated. Mass trapping and attract-and-kill can suppress pests, yet their success is more conditional because it depends on population density, immigration, target sex, lure competitiveness, trap retention, spatial deployment and persistence of the killing or release system. Plant volatiles, aggregation pheromones, repellents and herbivore-induced cues broaden the behavioural repertoire available for integrated pest management, although context dependence is greater and field validation is less mature. Digital camera traps, machine vision, receptor-guided discovery and biodegradable controlled-release matrices are important advances, but each introduces new validation requirements rather than eliminating ecological uncertainty. Across applications, the central translational weakness is a tendency to infer crop protection from behavioural response or trap capture without demonstrating injury, yield, economic or area-wide outcomes. Future progress requires standardised reporting of release rates and trap performance, multi-site field validation, explicit spatial design, integration with economic thresholds and biological control, and independent assessment of non-target and adoption consequences. Semiochemicals are therefore best understood not as stand-alone replacements for pesticides, but as information-rich components of ecologically designed pest management systems.