Search Results (540)

Resistance to the fumigant phosphine (PH₃) was studied for 28 populations of Rhyzopertha dominica from eight states of the USA and four provinces of Canada, as well as for 34 populations of Tribolium castaneum from twelve states of the USA and four provinces of Canada, using both a discriminating dose bioassay and molecular marker analysis. We used a molecular marker analysis for a point mutation in the gene that encodes dihydrolipoamide dehydrogenase and facilitates the “strong resistance” phenotype in both species. Our results showed that PH₃ resistance was correlated with higher frequencies of the strong resistance R allele in both species (R² = 0.59 in R. dominica and R² = 0.79 in T. castaneum). We also found that recessive R allele frequency did not correlate well with the geographic distribution of the resistant populations of these two species (R² = 0.21 in R. dominica and R² = 0.15 in T. castaneum). Therefore, populations of both species with higher R allele frequencies had higher resistance levels to PH₃. Our results showed that the geographic distribution of PH₃ resistance in both species varied and was not related geographically, but this supports the idea that the adaptive evolution of PH₃ resistance in these species is caused by selection pressure for their resistance genes. Full article

Protecting the soil ecosystem’s functioning is one of the main goals of recent regulations of chemicals. It is important to take soil biodiversity into account when designing cropping systems and measuring their impacts. Our main objective was to evaluate the effects of an organic amendment on soil nematode biodiversity compared to two years of fumigation. The plot-trial was conducted on tomato and lettuce plants under greenhouse, and free-living nematodes were used as bio-indicators of soil health. Treatments included a soil fumigant (applied once or twice over time), water control, and an organic substance. Soil samplings were carried out to determine the Meloidogyne incognita reproduction factor and the soil nematode community analysis using soil biological indicators. Data showed that soil fumigation clearly made the soil increasingly dependent on chemicals. Furthermore, fumigants suppressed pests and pathogens as well as their natural antagonists, causing a lack of biodiversity. While soils treated with organic matter respond slowly to stressors, they are progressively more suppressive thanks to biodiversity enrichment. Nematodes have proven to be useful indicators of the soil biota in response to biotic or abiotic disturbances. Their species richness and functional diversity make them valid bioindicators of soil management impact. Full article

Aspergillus carbonarius is one of the main pathogens responsible for postharvest diseases in fruits and is also one of the main ochratoxin A-producing strains. It not only causes significant economic losses but also poses a risk to human health. We found an inhibitory effect of dimethyl fumarate fumigation on the growth of A. carbonarius. To further explore its antifungal mechanism, this study elucidated the functions of key pathway-related genes through a transcriptomics analysis. A total of 1402 differentially expressed genes (DEGs) were identified, including 987 up-regulated and 415 down-regulated genes. Dimethyl fumarate was found to significantly inhibit the growth of A. carbonarius by disrupting cell integrity and obstructing mycelium growth and secondary metabolism. These findings provide a basis for the potential application of dimethyl fumarate in the food industry to inhibit A. carbonarius and subsequent ochratoxin A contamination. Full article

Νatural compounds such as lactic, acetic, formic, and oxalic acid and thymol are currently registered for use against Varroa destructor in apiaries in Europe. Complex botanical extracts are yet to be authorized, despite their beneficial ecofriendly profile and advantages in terms of resistance management. This study examined the fumigant activity of the essential oil (EO) of oregano, clove, lavender, dittany, bay laurel, sweet orange, peppermint, blue gum, and lemon balm against V. destructor in laboratory bioassays (Petri dishes). The most effective EOs were those of Origanum vulgare, Syzygium aromaticum, and Origanum dictamnus. These three EOs yielded 33.75% carvacrol, 58.64% eugenol, and 69.77% carvacrol and exhibited significant activity from 18 h of exposure to 0.0013 μL/cm until 48 h of exposure to 0.0068 μL/cm³. Origanum vulgare’s first calculated LC₅₀ value was 0.003 μL/cm³ after 24 h of mites’ exposure to EO vapors. The LC₅₀ values stabilized for oregano, clove, and dittany at 0.001, 0.002, and 0.002 μL/cm³ of 24 h exposure, respectively. This first indication of fumigant miticidal activity in Petri dishes is a promising first step before scaling up to field experiments. Full article

The oriental fruit fly (B. dorsalis) poses a critical threat to domestic mandarin trade, necessitating effective phytosanitary measures. This study evaluated ethyl formate (EF) and phosphine (PH₃) fumigation as alternative disinfestation methods, either alone or in combination with cold treatment, using B. scutellata, pumpkin fruit fly, as a surrogate species. Eggs and third-instar larvae were tested under both naked and inoculated conditions. Results indicated that larvae were more susceptible to treatment than eggs. The LT_99% values for cold treatment (1.7 °C) were 8.6 and 12.4 days under naked and inoculated conditions, respectively. EF LCt_99% values were 265.7 and 1111.0 g h/m³. EF (LCt_50%) combined with PH₃ (1.0 g/m³) achieved up to 100% mortality, while EF (LCt_50%) followed by cold treatment (1.7 °C for 1–3 days) significantly enhanced mortality compared to cold treatment alone. This study offers foundational data to optimize EF-based quarantine treatments against B. dorsalis, supporting shorter treatment times and more cost-effective quarantine practices. Future studies should validate these findings under practical field conditions. Full article

Aflatoxin contamination poses a significant food safety risk, particularly during the storage of dried chili peppers. This study evaluated the efficacy of formic acid treatment, ultraviolet (UV) treatment, and combined UV-formic acid treatment in both preventing and controlling Aspergillus flavus in dried red chili powder. Efficacy was assessed by measuring the growth diameter of A. flavus colonies on un-colonized and already colonized dried red chili powder. The optimal treatment conditions for the UV-formic acid combination were determined through single-factor experiments, orthogonal experiments, and quality assessment. Finally, the effects of the UV-formic acid combination on the cell membrane, antioxidant system, and energy metabolism of A. flavus were investigated. The results revealed that fumigation of un-colonized dried red chili powder with 5% formic acid for 24 h inhibited A. flavus growth by 93.29% and toxin synthesis by 99.41%. In contrast, treatment of already colonized chili powder with 10% formic acid inhibited A. flavus colony growth by 50%. Through a three-factor, three-level orthogonal experiment followed by quality testing, the optimal conditions were determined to be 8% formic acid concentration, a UV irradiation distance of 15 cm, and a treatment time of 75 min. This optimized combined treatment reduced the required fumigation time from 24 h to 1.25 h. This technique achieved complete suppression of aflatoxin B₁ synthesis on un-colonized dried red chili powder. On already colonized chili powder, the mycelial growth inhibition rate was 48.05 ± 6.68%, and aflatoxin B₁ synthesis was inhibited by 91.32 ± 3.15%. Quality assessment revealed that the UV-formic acid co-treatment parameters did not significantly affect key quality indicators including color, capsaicin content, total phenolic content (p > 0.05). Furthermore, UV-formic acid treatment disrupt the cell membrane structure of A. flavus, impairs its antioxidant and energy metabolism systems, and induces mitochondrial dysfunction. The study confirmed the synergistic antifungal effect of formic acid and UV, providing a potential industrialized solution for enhancing the safety and storage stability of dried chili products. Full article

Drosophila suzukii, classified as a quarantine pest in some countries, poses a serious threat to global trade due to its ability to damage berries and cherries. Recent studies indicate that low-temperature phosphine (PH₃) fumigation effectively controls this pest without compromising fresh produce quality. However, the specific protocol for managing D. suzukii larvae in cherries using this method remains underexplored. This study evaluates the efficacy of low-temperature PH₃ fumigation in controlling D. suzukii larvae across three cherry varieties at 3 °C and investigates potential effects on key quality metrics. Tolerance assessments revealed that 3rd instar larvae exhibit the highest resistance to PH₃ among all developmental stages. A concentration of 800 mL/m³ PH₃ for 84 h at 3 °C achieved phytosanitary efficacy for 0.99997 with no negative effect on the quality attributes of the tested cherry varieties. These results support low-temperature PH₃ fumigation as a viable postharvest treatment for D. suzukii management in sweet cherries. Full article

Cowpea, Vigna sp., is an important, low-cost protein source in subtropical and semi-arid regions, where seasonal rainfall makes storage necessary. However, the weevils Callosobruchus maculatus and C. chinensis cause significant grain losses during storage. While synthetic fumigants are commonly used to control these pests, their risks to mammals have prompted the search for safer alternatives. In this context, we tested palo santo, Bursera graveolens, essential oil with limonene, α-phellandrene, o-cymene and β-phellandrene, menthofuran, and germacrene-D as a sustainable approach. This plant is readily accessible, produces high fruit yields, and is used in households for various purposes. We evaluated the fumigant toxicity, repellency, and ovicidal effects of B. graveolens essential oil on both Callosobruchus species. Our results showed that B. graveolens oil was toxic to C. maculatus (LC₅₀ = 80.90 [76.91–85.10] µL) and C. chinensis (LC₅₀ = 63.9 [60.95–66.99] µL), with C. chinensis being more susceptible (SR = 1.27). Molecular docking analyses revealed that all the oil’s compounds bind to both the GABA and octopamine receptors, exhibiting high energy affinities; however, germacrene shows the strongest affinity in these receptors. C. chinensis was strongly repelled at all concentrations, while C. maculatus was repelled only at lethal concentrations. No ovicidal effect was observed in either species. In conclusion, our findings suggest that B. graveolens essential oil is a promising and sustainable protectant for stored cowpeas in small-scale storage units. Full article

Sitophilus zeamais, a major pest of stored grains, causes significant post-harvest losses and challenges effective control. While synthetic insecticides pose risks of resistance and toxicity, essential oils (EOs) offer a safer alternative. However, the insecticidal potential of their individual volatile constituents (VCs) remains largely unexplored. This study evaluated the insecticidal activity of 51 EO-derived volatile compounds (VCs) against S. zeamais, identifying the most toxic ones, optimizing 15 synergistic mixtures, and assessing their effects on key insect enzymes. A structure–activity relationship (SAR) analysis determined functional groups associated with insecticidal activity, while a cluster analysis pre-selected 29 ternary mixtures, later refined using response surface methodology (RSM). Additionally, enzymatic assays explored their impact on detoxification and nervous system enzymes, providing insights into potential mechanisms of action. Among the 51 VCs tested, 37 exhibited significant toxicity, with 11 acting as fumigants and 13 displaying contact toxicity. Monocyclic monoterpenoids with ketone or alcohol functional groups and exocyclic unsaturation demonstrated the highest insecticidal activity via both exposure routes. Notably, pulegone enantiomers were particularly effective (LC₅₀ < 0.1 mg/L, LD₅₀ < 7.5 µg/adult). Among the optimized mixtures, 10 displayed strong insecticidal effects, 8 were active through both routes, and 5 exhibited synergistic fumigant interactions. The most effective formulations were M2 (R-pulegone + S-pulegone + S-carvone, LC₅₀ 0.48 mg/L) and M20 (isopulegone + δ-3-carene, LC₅₀ 2.06 mg/L), showing the strongest fumigant and synergistic effects, respectively. Enzymatic assays revealed that while some compounds mildly inhibited GST and CAT, others, such as δ-3-carene (IC₅₀ 0.19 mg/L), significantly inhibited AChE. Five mixtures exhibited synergistic neurotoxicity, with M20 (IC₅₀ 0.61 mg/L) and M12 (IC₅₀ 0.81 mg/L) emerging as the most potent AChE inhibitors. These findings highlight the potential of plant-derived volatile compounds as bioinsecticides, leveraging synergistic interactions to enhance efficacy, disrupt enzymatic pathways, and mitigate resistance. Full article

Recently, a new solarization method gained a great deal of attention thanks to various advantages in comparison with both the traditional one and soil fumigation (alternative soil treatment based on the use of chemical agents). This method implements traditional solarization by spraying a biodegradable black liquid over the soil surface before the application of a thermic film. This creates a thin black film that acts like a “black body”, significantly increasing soil temperatures at various depths. Thanks to higher temperatures, it is possible to eliminate most of the pathogens in shorter times compared to traditional solarization. In the present paper, the results of different trials carried out on green beans, Romanesco broccoli, and lettuce were reported. The aims of this work were to demonstrate the efficacy on soil borne pathogens, its lower impact on living soil fungal biodiversity and the agronomical performance of the new solarization method. All crops tested showed a significant yield increase when grown in soil treated with the innovative solarization method. Romanesco broccoli also exhibited improved inflorescence quality. Solarization had a positive impact on overall crop productivity: green beans showed a maximum yield increase of 165.3%, lettuce yields rose by 47.5%, and Romanesco broccoli yields were 111.5% higher compared to the non-solarized control. These results confirm that the new solarization method is more effective, as well as environmentally, economically, and socially sustainable compared to traditional methods. Full article

In this study, a historically significant journal subject to fungal colonization was used as a case study for experimenting with a fumigation treatment using essential oils. The experiments were carried out both in vitro and in vivo directly on the artifact. Post-treatment monitoring showed that the succession of two fumigation treatments (alternately using rosemary and lavender oil) resulted in the complete disinfection of the first and second populations detected on the substrate. The latter was identified as Trichoderma longibrachiatum, a human pathogenic species, which was found to be sensitive to various concentrations of rosemary essential oil (1.2% v/v) and lavender essential oil (0.4% v/v), while it was not contained by the standard biocide based on benzalkonium chloride. The results obtained allowed the proposal of an application protocol for the fumigation of paper items that need to undergo biocidal treatment, which consists of alternating essential oils to increase the action spectrum of the natural substances and implementing a rotation principle to prevent the development of bio-resistances. Full article

To study the effects of different microbial agents on the microbial community structure of continuously cropped strawberry soil after soil fumigation, seven treatments were applied: T1 (Trichoderma harzianum + Bacillus subtilis + actinomycetes), T2 (Trichoderma harzianum + Bacillus subtilis), T3 (Trichoderma harzianum + actinomycetes), T4 (CK) (water control), T5 (Bacillus subtilis), T6 (actinomycetes) and T7 (Trichoderma harzianum). A high-throughput sequencing platform (Illumina HiSeq 2500) was used to analyze the soil bacterial and fungal communities and their compositions. Compared with the T4 (CK) treatment, the application of microbial agents increased the richness and diversity of soil bacteria and fungi, and the effects of single microbial agents and compound microbial agents differed. The richness, diversity indices and population sizes of bacteria and fungi in the T6 treatment were the highest. The Chao1, observed species and Shannon indices of bacteria were 22.51%, 23.56% and 5.61% greater, respectively, than those of T4 (CK). The Chao1, observed species, Shannon and Simpson indices of fungi were 41.28%, 41.83%, 128.02% and 88.65% higher, respectively, than those of T4 (CK). At the genus level, the bacterial community compositions of T2 and T6 were the most similar, and the fungal community compositions of T1 and T5 were the most similar. Analysis of the genera in the dominant communities revealed that the application of microbial agents after dazomet fumigation increased the numbers and recovery rates of soil bacteria and fungi, especially the beneficial fungal genera, Lecanicillium, Cladosporium, Saccharomyces and Aspergillus. An investigation of strawberry growth and yield-related indicators revealed that the T6 treatment resulted in the lowest seedling mortality and the highest yield. In summary, adding microbial agents to soil with continuous cropping of strawberry after fumigation with dazomet is a scientifically sound and effective method for reconstructing the balance of the soil microbial flora and overcoming the obstacles associated with continuous cropping. In this study, the T6 (actinomycetes) treatment presented the best performance. Full article

Pest control in industrial buildings, such as silos and storage facilities, is critical for maintaining food safety and economic stability. Traditional methods like fumigation face challenges, including insect resistance and environmental concerns, prompting the need for alternative approaches. Heat treatments have emerged as an effective and eco-friendly solution, but optimizing their duration and efficiency remains a challenge. This study leverages machine learning (ML) to predict the duration of heat treatments required for effective pest control in various industrial buildings. Using a dataset of 1423 heat treatment time series collected from IoT devices, we applied exploratory data analysis (EDA) and ML models, including random forest, XGBoost, ridge regression, and support vector regression (SVR), to predict the time needed to reach 50 °C, a critical threshold for pest mortality. Results revealed significant variations in treatment effectiveness based on building type, geographical location, and ambient temperature. XGBoost and random forest models outperformed others, achieving high predictive accuracy. The findings highlight the importance of tailored heat treatment protocols and the potential of data-driven approaches to optimize pest control strategies, reduce energy consumption, and improve operational efficiency in industrial settings. This study underscores the value of integrating IoT and ML for real-time monitoring and adaptive control in pest management. Full article

The contributions of de novo synthesis to terpene emissions from Eucalyptus globulus subsp. globulus were determined by fumigating branchlets with ¹³CO₂ in a gas exchange system. Of more than thirty-four terpenes emitted by this species, only four, i.e., isoprene, iso-valeraldehyde, cis-ocimene, and trans-caryophyllene, incorporated ¹³C into the terpene carbon skeleton during the ~5–6 h experiment. ¹³C incorporation into isoprene and iso-valeraldehyde reached a maximum of ca. 82% of the carbon skeleton, similar to cis-ocimene, with a maximum of 77% ¹³C incorporation after ~2.5 h exposure to ¹³CO₂. Only ca. 20% of carbon was labelled in trans-caryophyllene after 5–6 h. the incorporation of ¹³C was observed only in compounds emitted from leaves, and was not detected in either individual oil glands or in bulk leaf tissue. The results suggest the de novo synthesis of some terpenes (isoprene, cis-ocimene, trans-caryophyllene, and iso-valeraldehyde) and their emission is independent of emissions of terpenes stored in oil glands. Full article

The house fly, Musca domestica L., is a pest of great medical and agricultural importance, serving as a vector for various diseases and undermining the quality of agricultural products. Traditionally, synthetic insecticides have been the primary means of control; however, their efficacy has declined over time, and they are now less preferred due to their safety and environmental concerns. This study evaluated the insecticidal and repellent properties of essential oils from Eucalyptus globulus, Foeniculum vulgare and Salvia officinalis against M. domestica. All EOs exhibited insecticidal activity: eucalyptus achieved 100% fumigant mortality at 34 µL L⁻¹ air and showed the lowest LC₅₀ (18.1 µL L⁻¹ air), while fennel and sage required 50 µL L⁻¹ air. In contrast, fennel showed the highest contact toxicity (100% mortality at 150 µL L⁻¹). Repellency exceeded 87% for all EOs, with sage being the most repellent at the lowest concentration tested (94% at 5 µL L⁻¹). These results highlight the potential use of essential oils and their constituents as environmentally friendly alternatives for the control of M. domestica. However, further field validation and studies on individual components and their synergistic combinations are needed to understand their efficacy and fully optimize their use. Full article