Black soldier fly, H. illucens larvae, efficiently convert low-value organic substrates into high-value products, offering solutions to global challenges in sustainable food production and biotechnology. This study investigated the impact of dietary protein levels (10%, 14%, 16%, and 20% crude protein, CP) on BSFL growth, nutrient utilization, and energy retention using isoenergetic diets (18.5 ± 0.3 MJ/kg dry matter) under commercial-scale conditions. Larvae were harvested after 8 days of feeding, with 5 replicates per treatment. Optimal growth performance and feed conversion ratios were observed in larvae fed 14% CP diet, with a quadratic relationship between dietary CP and biomass gain (p < 0.001, R² = 0.870). Ash and calcium deposition peaked in CP20-fed larvae and were lowest in CP14-fed larvae. Phosphorus and glucosamine deposition remained unaffected, while chitin deposition correlated positively with larval weight. Nitrogen and amino acid retention were highest in CP14-fed larvae but reduced in CP20-fed larvae (p < 0.001, R² = 0.573–0.902). CP10-fed larvae showed impaired growth and nitrogen deposition but increased fat deposition. These findings establish the CP14 diet as the optimal formulation for scalable BSFL production, providing critical insights into dietary protein effects on BSFL physiology and enabling the development of efficient feeding strategies for industrial-scale farming.

Climate change increasingly threatens potato production through intensified drought stress and emergence of vector-transmitted diseases. This study evaluated straw mulch application as a dual-purpose climate adaptation strategy to enhance potato performance under drought conditions and reduce the incidence of bacterial potato tuber wilt (BPW) caused by ‘ Candidatus Arsenophonus phytopathogenicus’ and ‘ Candidatus Phytoplasma solani’, transmitted by the planthoppers Pentastiridius leporinus and Hyalesthes obsoletus . Field trials conducted from 2022 to 2024 in Bingen am Rhein, Germany, tested five potato cultivars under mulched and unmulched conditions. Complementary greenhouse choice experiments investigated oviposition preferences of P. leporinus in response to soil type and mulch cover. The magnitude of mulch benefits correlated directly with drought severity, demonstrating greatest efficacy under high-stress conditions. Mulch application increased tuber yield by 33% overall, though effects varied significantly across years ( p = 0.003) and cultivars ( p = 0.006), with cultivar Darling showing exceptional drought responsiveness (119% yield increase under severe drought conditions). Mulch significantly reduced rubbery tuber incidence by 22% ( p = 0.019) and showed marginal reduction in wilting symptoms (29%, p = 0.072). In contrast, greenhouse experiments revealed mulch significantly increased vector oviposition ( p < 0.001), particularly at the straw surface layer. These findings demonstrate that mulch operates through complex ecological pathways that buffer drought stress and enhance disease tolerance despite increased vector reproduction. The net positive outcomes for both yield and disease management under drought conditions support strategic mulch deployment as a valuable climate adaptation tool, particularly when integrated with drought-responsive variety selection and precision management frameworks that balance enhanced vector habitat with improved plant resilience under combined abiotic and biotic stresses. This research provides the first comprehensive evaluation of cultivar-specific responses to mulch under combined drought and bacterial pathogen pressure, offering practical insights for sustainable potato production in changing climatic conditions.

Climate change increasingly challenges potato production through intensified drought stress and emerging vector-transmitted diseases. This study evaluated straw mulch application as a climate adaptation strategy across three field seasons (2022–2024) in Bingen am Rhein, Germany, testing five potato cultivars under varying drought conditions and bacterial pathogen pressure from Pentastiridius leporinus , a vector of 'Candidatus Phytoplasma solani' and 'Candidatus Arsenophonus phytopathogenicus'. Complementary greenhouse choice-experiments investigated vector oviposition preferences on different soil types and mulch coverage.Field trials revealed significant year × variety interactions in yield responses to mulch treatment, with effects strongly correlated to drought severity. Under mulch treatment, Darling achieved a 119% yield increase during severe stress conditions (2022), while Almonda and Jule showed substantial responses to mulching (77% and 90% increases respectively in 2023). Mulch treatment significantly reduced bacterial potato tuber wilt incidence by 22% (p = 0.019) and reduced wilting symptoms by 29% (p = 0.072). The magnitude of mulch benefits correlated directly with drought severity, demonstrating greatest efficacy under high stress conditions. Controlled greenhouse choice-experiments provided insights into vector behavior, revealing that P. leporinus preferred straw-covered over bare soil (χ²=25.15, p < 0.001) and loam over sandy substrates (χ²=15.54, p < 0.001) for oviposition.These findings demonstrate that mulch operates through multifaceted mechanisms involving stress tolerance and complex plant-vector-pathogen interactions rather than simple vector deterrence. The net positive outcomes for both yield and disease management under drought conditions support strategic mulch deployment as a valuable climate adaptation tool, particularly when integrated with cultivar selection and environmental forecasting. This research provides the first comprehensive evaluation of cultivar-specific responses to mulch under combined drought and bacterial pathogen pressure, offering practical insights for sustainable potato production in changing climatic conditions.

The rearing of black soldier fly larvae represents a sustainable approach to organic waste valorisation and animal feed production. However, substrate composition is known to influence larval growth, nutrient assimilation and body composition. This study evaluated the effects of seven food industry by-products – carrot scraps, grape pomace, biscuit meal, bread crumbs, wheat bran, wheat pulp and rapeseed cake – compared to the standard Gainesville diet under commercial rearing conditions. Larvae were maintained in 144 containers (approximately 14 000 larvae per container) within a climate-controlled room. Each of the eight treatments was replicated 18 times, with six replicates harvested on days 4, 8 and 12 post-hatching for analysis. Substrate type significantly affected growth, survival and feed conversion, with interactions between substrate and harvest time ( ). Wheat bran yielded the highest survival rate, biomass gain and feed conversion efficiency, whereas carrot scraps and grape pomace resulted in the lowest values. Nitrogen retention was greatest in larvae fed wheat bran, while wheat pulp and rapeseed cake showed the lowest retention. Biscuit meal and bread crumbs improved energy retention compared to carrot scraps and grape pomace. Frass composition closely reflected substrate nutrient profiles, particularly nitrogen and energy content. Harvest timing also significantly influenced both larval and frass composition. These findings highlight the critical role of substrate selection in optimising nutrient utilisation, growth performance and biomass yield in BSFL production.