Periodic Reporting for period 2 - REACT (Rapid elimination of invasive insect agricultural pest outbreaks by tackling them with Sterile Insect Technique programs)
Reporting period: 2024-05-01 to 2025-10-31
REACT (Rapid elimination of invasive insect agricultural pest outbreaks by tackling them with Sterile Insect Technique programmes) develops rapid, environmentally sustainable tools to protect EU fruit and vegetable production, trade and biodiversity from invasive fruit flies. It targets two EU-priority pests, Bactrocera dorsalis (Bd) and Bactrocera zonata (Bz), which can cause severe yield and quality losses and costly emergency measures. Increased trade and mobility, together with changing climatic conditions, raise the likelihood of introductions and establishment, making prevention, early detection and rapid response essential.
REACT’s pathway to impact is an EU-ready rapid response package combining: (i) faster detection and reliable species identification, including at the larval stage; (ii) improved evidence and predictive models describing establishment, spread and seasonal dynamics under European conditions; and (iii) operational readiness for area-wide control using the Sterile Insect Technique (SIT). SIT suppresses populations by releasing sterile males that mate with wild females, producing no viable offspring and a progressive reduction in pest abundance. As a species-specific method compatible with Integrated Pest Management (IPM), SIT is a sustainable alternative to broad-spectrum insecticides while maintaining effective area-wide control.
Social sciences and humanities contribute through structured stakeholder consultation and socio-economic analyses, enabling transparent comparison of response options (costs, benefits, constraints and expected outcomes) and supporting evidence-based decision-making.
REACT’s pathway to impact is an EU-ready rapid response package combining: (i) faster detection and reliable species identification, including at the larval stage; (ii) improved evidence and predictive models describing establishment, spread and seasonal dynamics under European conditions; and (iii) operational readiness for area-wide control using the Sterile Insect Technique (SIT). SIT suppresses populations by releasing sterile males that mate with wild females, producing no viable offspring and a progressive reduction in pest abundance. As a species-specific method compatible with Integrated Pest Management (IPM), SIT is a sustainable alternative to broad-spectrum insecticides while maintaining effective area-wide control.
Social sciences and humanities contribute through structured stakeholder consultation and socio-economic analyses, enabling transparent comparison of response options (costs, benefits, constraints and expected outcomes) and supporting evidence-based decision-making.
REACT advanced a coherent set of technical and scientific components required for a rapid, area-tailored response to invasive fruit fly incursions.
To enable earlier and more targeted action, REACT developed and validated diagnostic tools for larval interception. A portable Prototype Interception Kit (PIK) was tested on field samples and demonstrated high identification accuracy in blind trials. Molecular reagents remained functional for approximately six months under cold storage, supporting practical deployment in operational settings. The diagnostic workflow was further extended to include higher-throughput options, such as pooled-larva testing and exploratory whole-fruit homogenate approaches, to simplify sample preparation during inspections.
The project generated new biological evidence relevant for preparedness and risk assessment, including studies on invasion drivers, survival and seasonal performance. Overwintering experiments under fluctuating winter temperature regimes showed that adults can survive for more than 200 days and revealed species-specific differences in cold tolerance between Bd and Bz. These findings strengthen the evidence base for establishment potential under European climatic conditions. Population structure and dispersal studies further provided insights into seasonal population dynamics, supporting improved timing of surveillance and intervention measures.
REACT strengthened modelling and decision-support capacity by developing species-specific Bd and Bz sub-models within the PESTonFARM platform. Scenario simulations were used to explore how climate, landscape structure, and intervention timing influence outbreak development and response requirements. In parallel, a multidimensional cost-benefit model was advanced to compare management strategies, incorporating environmental and health dimensions associated with pesticide use and enabling more comprehensive evaluation of response options.
Operational readiness for the SIT progressed through advances in mass-rearing and quality improvements. REACT established an emergency-response rearing capacity of up to 500,000 sterile males per week and developed improved diets and quality-control procedures to support consistent production of competitive sterile males. Diet optimization included the use of bacterial biomass (including Enterobacter-based approaches) and cost-reduction strategies based on food-industry by-products, while maintaining biological performance.
For longer-term SIT implementation, REACT accelerated progress toward Genetic Sexing Strains (GSS), which enable male-only releases and improve SIT operational efficiency. CRISPR-based “white pupae” mutant lines were created and characterised as entry points for GSS development, supported by improved genome assemblies, sex-chromosome discovery pipelines, and proof-of-concept work on Y-linked marker approaches. Complementary metabolomics and related pipelines were established to identify objective biomarkers associated with male quality, strengthening evidence-based quality management for SIT programmes.
To enable earlier and more targeted action, REACT developed and validated diagnostic tools for larval interception. A portable Prototype Interception Kit (PIK) was tested on field samples and demonstrated high identification accuracy in blind trials. Molecular reagents remained functional for approximately six months under cold storage, supporting practical deployment in operational settings. The diagnostic workflow was further extended to include higher-throughput options, such as pooled-larva testing and exploratory whole-fruit homogenate approaches, to simplify sample preparation during inspections.
The project generated new biological evidence relevant for preparedness and risk assessment, including studies on invasion drivers, survival and seasonal performance. Overwintering experiments under fluctuating winter temperature regimes showed that adults can survive for more than 200 days and revealed species-specific differences in cold tolerance between Bd and Bz. These findings strengthen the evidence base for establishment potential under European climatic conditions. Population structure and dispersal studies further provided insights into seasonal population dynamics, supporting improved timing of surveillance and intervention measures.
REACT strengthened modelling and decision-support capacity by developing species-specific Bd and Bz sub-models within the PESTonFARM platform. Scenario simulations were used to explore how climate, landscape structure, and intervention timing influence outbreak development and response requirements. In parallel, a multidimensional cost-benefit model was advanced to compare management strategies, incorporating environmental and health dimensions associated with pesticide use and enabling more comprehensive evaluation of response options.
Operational readiness for the SIT progressed through advances in mass-rearing and quality improvements. REACT established an emergency-response rearing capacity of up to 500,000 sterile males per week and developed improved diets and quality-control procedures to support consistent production of competitive sterile males. Diet optimization included the use of bacterial biomass (including Enterobacter-based approaches) and cost-reduction strategies based on food-industry by-products, while maintaining biological performance.
For longer-term SIT implementation, REACT accelerated progress toward Genetic Sexing Strains (GSS), which enable male-only releases and improve SIT operational efficiency. CRISPR-based “white pupae” mutant lines were created and characterised as entry points for GSS development, supported by improved genome assemblies, sex-chromosome discovery pipelines, and proof-of-concept work on Y-linked marker approaches. Complementary metabolomics and related pipelines were established to identify objective biomarkers associated with male quality, strengthening evidence-based quality management for SIT programmes.
REACT integrates field-ready diagnostics, strengthened evidence on establishment and persistence, decision-support modelling and SIT building blocks into a single rapid-response framework tailored to European conditions, moving beyond fragmented tools toward an end-to-end response pathway.
The PIK addresses a key early-detection gap by enabling portable, species-level identification in about 90 minutes, scalable for borders and outbreak investigations, particularly at the larval stage.
Experimental evidence on extended adult overwintering and species-specific cold tolerance refines preparedness assumptions and improves risk assessment and planning of surveillance and control across seasons. Combined with species-specific modelling and multidimensional cost-benefit analysis, REACT enables more transparent, evidence-based comparison of response options under realistic ecological and economic conditions.
For SIT, “white pupae” mutants and improved genomic resources establish a transferable framework to accelerate GSS development, a prerequisite for efficient male-only releases. Metabolomics-based indicators introduce objective, biology-driven measures that complement traditional quality metrics and support standardisation and reliability in SIT operations.
To maximise uptake, further steps include continued validation of diagnostics in official phytosanitary and control settings, completion of fitness and stability assessment for emerging GSS prototypes, and deeper integration of biological, modelling and economic outputs into practical outbreak-response playbooks across crops and regions.
The PIK addresses a key early-detection gap by enabling portable, species-level identification in about 90 minutes, scalable for borders and outbreak investigations, particularly at the larval stage.
Experimental evidence on extended adult overwintering and species-specific cold tolerance refines preparedness assumptions and improves risk assessment and planning of surveillance and control across seasons. Combined with species-specific modelling and multidimensional cost-benefit analysis, REACT enables more transparent, evidence-based comparison of response options under realistic ecological and economic conditions.
For SIT, “white pupae” mutants and improved genomic resources establish a transferable framework to accelerate GSS development, a prerequisite for efficient male-only releases. Metabolomics-based indicators introduce objective, biology-driven measures that complement traditional quality metrics and support standardisation and reliability in SIT operations.
To maximise uptake, further steps include continued validation of diagnostics in official phytosanitary and control settings, completion of fitness and stability assessment for emerging GSS prototypes, and deeper integration of biological, modelling and economic outputs into practical outbreak-response playbooks across crops and regions.