Search Results (169)

The house cricket, Acheta domesticus, is found globally. It is an agricultural pest causing economic damage to a wide variety of crops including cereal seedlings, vegetable crops, fruit plants, and stored grains. Additionally, crickets act as mechanical vectors of pathogens by harboring bacteria, fungi, viruses, and toxins, causing foodborne illnesses. They can contaminate stored grains, packaged foods, or animal feed due to deposition of their feces, lowering the quality of the food and creating food safety risks. Synthetic insect repellents, such as pyrethroids and carbamates, have been used previously in integrated pest management practices to control crickets. Though successful as repellents, they have been associated with health and environmental risks and concerns. The use of organic green repellents, such as plant essential oils, may be a viable alternative in pest management practices. In this study, we tested the effects of 27 plant-based essential oils on the behavior of A. domesticus. A. domesticus were introduced into an open arena to allow them unrestricted movement. A transparent plastic bottle containing an essential oil treatment was placed in the arena to allow voluntary entry by the crickets. Following a predetermined observation period, the number of crickets that entered the bottle was recorded, and percent entry was calculated as the proportion of individuals inside the bottle relative to the total number in the arena. Analysis of the percentage entry into the bottles allowed for a comparative assessment of repellency of the selected essential oils examined in this study. Essential oils that elicited high levels of entry into the bottle were categorized as having weak or no repellency, while those that demonstrated reduced entry were classified as moderate or strong repellents. Our results indicated that A. domesticus responded with strong repellent behavior to nearly half of the essential oils tested, while four essential oils and two synthetic repellents evoked no significant repellent responses. Four strong repellent essential oils, namely peppermint, rosemary, cinnamon, and lemongrass, were tested at different concentrations and showed a clear dose-dependent repellent effect. The results suggest that selected essential oils can be useful in the development of more natural “green” insect repellents. Full article

To control maize weevils (Sitophilus zeamais), a major pest of stored grains, this study explores the use of essential oils from Eucalyptus globulus and Lantana camara as natural biopesticides. Given the risks of synthetic pesticides, these oils offer a sustainable alternative. The research first identified ten fungal pathogens associated with the weevils, including the dominant species, Fusarium solani. Preliminary results showed that both oils were then tested for their ability to kill the fungi and the weevils. Eucalyptus globulus oil proved to be a superior antifungal agent, inhibiting fungal growth by up to 93%, significantly outperforming Lantana camara oil. Both oils demonstrated potent insecticidal properties, achieving 100% weevil mortality at a 10% concentration within 24 hrs. However, Eucalyptus oil was more effective, maintaining 100% mortality even at a lower 5% concentration, unlike Lantana oil. Chemical analysis showed that Eucalyptus oil’s high effectiveness may be associated with its main component, eucalyptol (52.8%). Lantana oil had a more varied composition, with caryophyllene (31%) as its primary constituent. The findings suggest that Eucalyptus globulus essential oil is a promising, two-in-one biopesticide capable of controlling both maize weevils and their associated fungal pathogens. Full article

Microwave heating has been widely used for disinfestation in the food industry due to its selective heating. However, research on the effects of microwave heating on stored product insects is still relatively limited, which has restricted its broader application in grain pest control storage. Therefore, this study evaluated the lethal effects of different microwave powers and exposure times on three major pests in paddy and investigated the impact of microwave treatment on improving adult detection efficiency, intending to develop a rapid and efficient detection method for stored grain insects. The results showed that the mortality of Sitophilus oryzae, Tribolium castaneum, and Oryzaephilus surinamensis increased with the increase in microwave power and exposure time. Specifically, 100% mortality was achieved for both S. oryzae and T. castaneum at 700 W for 60 s exposure. However, higher power levels and longer exposure durations exacerbated the non-uniformity of grain temperature distribution and adversely affected the germination rate. In addition, microwave treatment at 350 W, 490 W, and 700 W significantly reduced fungal load in paddy. The moisture content and water activity of rice decreased with the increase in microwave power and exposure time, while the percentage of grain breakage remained largely unaffected. These findings indicated that microwave treatment can effectively control insects and fungi without significantly altering the main physical properties of paddy. Notably, microwave treatment with short exposure durations (20–30 s) at all three power levels is conducive to increasing the recovery percentage of S. oryzae adults, while microwave treatment at low power (350 W) with exposure durations of 25–40 s helps improve that of T. castaneum. Accordingly, microwave heating is not only a promising strategy for protecting stored grains but also has potential for development as a rapid detection method for specific insect pests. Full article

Mating disruption (MD) is an environmentally friendly pest management approach that uses synthetic pheromones to interfere with insect mate location and reproduction. This review summarizes current progress in the application of MD for stored-product pests, with emphasis on Lepidoptera (Plodia interpunctella Hübner and Ephestia kuehniella Zeller (Pyralidae)) and Coleoptera (Sitophilus spp. (Curculionidae)). For moth pests, numerous studies have demonstrated substantial suppression of mating and population growth under both laboratory and field conditions, particularly when MD is integrated with sanitation, monitoring and other IPM measures. Conversely, MD applications against beetles have been less successful due to their aggregation-based communication and lower volatility of their pheromones. Advances in pheromone formulation technology, including polymer dispensers, microencapsulated sprays and aerosol emitters, have improved pheromone stability and controlled release, although achieving uniform coverage in large and aerated storage environments remains challenging. The integration of MD with biological control, temperature management and reduced fumigant use offers promising directions for sustainable pest suppression. Continued development of smart-release devices, long-term field validation and integration with automated monitoring systems will further enhance the feasibility and cost-effectiveness of MD. Overall, MD represents a key behavioral component in reducing pesticide reliance and promoting sustainable management of stored-product pests. Full article

To address the issues of resistance and food safety stemming from the overuse of chemical fumigants in stored-grain pest control, this study aimed to systematically optimize the insecticidal process of pulsed electric field (PEF) treatment on Tribolium castaneum (T. castaneum) and to investigate its electro-neurotoxicity mechanism. Single-factor experiments were used to determine parameter ranges, and response surface methodology (RSM) was employed to analyze the effects of electric field strength, pulse frequency, and treatment time. The finite element method (FEM) was used to simulate the physical field distribution, and acetylcholinesterase (AChE) activity was measured to explore neurotoxicity. The results indicated that electric field strength, pulse frequency, and treatment time all had highly significant effects (p < 0.0001), with electric field strength being the primary factor. The optimal process parameters were determined to be: electric field strength of 26 kV/cm, pulse frequency of 20 kHz, and treatment time of 140 s. Under these conditions, the predicted and actual mortality rates were both 100%, and this efficacy was validated in rice samples. Simulation confirmed that PEF achieves physical targeting through a “tip effect” on the insect’s nerve endings; mechanism tests demonstrated that PEF treatment significantly inhibited AChE activity (p < 0.01). This study confirms the “electro-neurotoxicity” mechanism of PEF, providing theoretical support for this green physical control technology. Full article

Purple maize and canary beans are economically important crops in Peru, grown for domestic and international markets. However, postharvest storage losses are a major challenge along the value chain due to insect pests. This study evaluated the efficacy of the Purdue Improved Crop Storage (PICS) and polypropylene (PP) bags in storing both crops in the Arequipa region, Peru. Oxygen and CO₂ levels were monitored every month. Insect pests, germination rates, sugar content, peroxide index, moisture content, and colony-forming units (CFU) were measured at the start and nine months after storage to determine the level of grain deterioration. PICS maintained a hypoxic environment that suppressed insect development and limited grain damage and weight loss to below 1%. In contrast, PP bags allowed infestations to escalate, resulting in weight losses of about 20% for each crop. Germination declined markedly in PP for both crops; in PICS, it remained high for purple maize (87.5%) but fell substantially for canary beans (20.8%). Moisture rose modestly in PICS, yet deterioration markers, including sugar content and peroxide index, were lower than in PP bags. Although Fusarium, Aspergillus, and Penicillium were detected in purple maize across both systems, mold loads were far lower in PICS. Overall, hermetic storage in PICS bags is effective in reducing postharvest losses and preserving important quality characteristics of beans and maize in Peru. Full article

Sitophilus zeamais is one of the most destructive pests of stored grains. Both adults and larvae penetrate and consume the grains, thereby diminishing the grain quality and nutritional value. We determined the chemical composition of Angelica archangelica essential oil, its fumigation toxicity against S. zeamais, and its effects on the activities of detoxification enzymes in the insects. RNA-seq was performed to analyze the impact of the essential oil on the transcriptional level of S. zeamais, and qRT-PCR was conducted to validate the differentially expressed genes. Chemical analysis identified 35 components in essential oil, including δ-3-Carene (24.26%), Limonene (19.81%), and α-Pinene (14.96%). A significant positive correlation was observed between the fumigation activity of the essential oil and the applied dose. The median lethal concentrations (LC₅₀) values were 164.38, 132.62, and 90.35 mg/L air at 24, 48, and 72 h, respectively. Fumigation significantly inhibited the activities of the three detoxification enzymes. RNA-seq revealed a total of 3718 significantly differentially expressed genes (DEGs). qRT-PCR confirmed that the expression patterns of the DEGs were consistent with the RNA-seq data. This study comprehensively evaluates the control efficacy of A. archangelica essential oil against S. zeamais and provides data support for developing novel, eco-friendly, plant-based pesticides. Full article

Tenebrio molitor is a common stored grains pest. The conventional way for its management involves the use of synthetic fumigants. Despite their effectiveness, these can cause environmental damage. The use of essential oils has emerged as an alternative for its management. Therefore, the aim of this study was to assess Lantana camara essential oil (EO) and endo-borneol biological activities against T. molitor. Insecticidal activity and weight gain were evaluated through the impregnated paper method against larvae and adults, while repellency was conducted with a Y-tube olfactometer; L. camara EO showed higher mortality for T. molitor adults (LC₅₀ = 7.2 μL EO L⁻¹ air) than for larvae (LC₅₀ = 13.7 μL EO L⁻¹ air) after 30 d. Furthermore, L. camara EO was found to be repellent for T. molitor adults (RC₅₀ = 0.08 μL EO cm⁻²). Regarding the EO composition, endo-borneol was identified by GC-MS as a major compound with 14.24% abundance. Larvae exhibited higher susceptibility (LC₅₀ = 7.8 μL L⁻¹ air) to endo-borneol than adults (LC₅₀ = 46 μL L⁻¹ air) after 72 h. Notably, endo-borneol demonstrated significantly higher repellent activity (RC₅₀ = 0.03 μL cm⁻²) than L. camara EO (RC₅₀ = 0.08 μL EO cm⁻²). These findings suggest that endo-borneol has potential as a natural source alternative for T. molitor management. Full article

Nitrogen-modified atmosphere technology, due to its effectiveness in pest control, is widely used in grain storage as an eco-friendly preservation method. This study compared the quality changes in unhulled rough rice (paddy) stored under nitrogen-modified atmosphere and conventional conditions. Fatty acid value (FAV), reactive oxygen species (ROS) content, coenzyme levels, antioxidant enzyme activities, and concentrations of central carbon metabolism-related metabolites of paddy were monitored during storage under different storage conditions. The results revealed that compared to conventional storage, nitrogen-modified atmosphere resulted in lower FAV and ROS levels, as well as higher pyridine nucleotides contents and antioxidant enzyme activities, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione reductase (GR). Metabolomic profiling demonstrated that N₂-MAS induced metabolic changes characterized by the down-regulation of 2-hydroxyglutaric acid and the up-regulation of fructose 6-phosphate, glucose 1-phosphate, glycerol 3-phosphate, gluconic acid, fumaric acid, and malic acid, which collectively contribute to reduced oxidative damage and enhanced preservation quality. These findings elucidated the mechanism of N₂-MAS-delayed quality deterioration and revealed the regulatory role of the antioxidant system and central carbon metabolism. Full article

Botanical insecticides have gained interest due to a rising demand for environmentally friendly pest control methods for stored-product protection. The insecticidal effectiveness of the essential oil (EO) obtained from the oleo-gum-resin of myrrh (Commiphora myrrha (Nees) Engl.), against Prostephanus truncatus (Horn) and Sitophilus zeamais Motschulsky, and the metabolic shifts of the two species, were investigated in this work. A thorough gas chromatography-mass spectrometry (GC-MS) investigation showed that the composition of this EO was dominated by furanosesquiterpenes, specifically, furanoeudesma-1,3-diene and curzerene. Commiphora myrrha EO treatments, especially at 1000 ppm, resulted in high adult mortality for P. truncatus (up to 85.6%), while S. zeamais showed only moderate mortality (up to 25.6%). To investigate the different species-specific effectiveness of the EO, untargeted GC-MS metabolomic profiling was conducted to elucidate the impact of the EO on the metabolism of the insects, with subsequent data analysis employing multivariate, univariate, and network methods. Each species reacts differently to the treatments (myrrh EO versus the synthetic insecticide pirimiphos-methyl (PM)), according to the analysis results. In particular, myrrh EO caused distinct shifts in metabolic pathways that varied between P. truncatus and S. zeamais. Overall, C. myrrha EO exhibits potential as a botanical insecticide, especially against P. truncatus, and it causes metabolic disturbances specific to the species. The results demonstrate the significance of metabolomic technologies in assessing bioinsecticide mechanisms and lend credence to their possible incorporation in integrated pest management methodologies or their contribution to the creation of diagnostic indicators of insecticidal exposure. Full article

The relative efficacy of amorphous silica dusts, malathion, and pirimiphos methyl was assessed against S. oryzae and T. castaneum in stored wheat under laboratory conditions. Insecticidal performance was influenced by physical properties such as particle size, surface area, bulk density, and oil/water adsorption capacity. Fumed silicas showed the highest toxicity, particularly Wacker HDK H20 (LC₅₀ = 19.4 mg/100 g at 12% moisture). Precipitated silica, Sipernat 22, though less potent (LC₅₀ = 46.6 mg/100 g), displayed consistent efficacy across different moisture levels, making it a suitable inert carrier. Increasing grain moisture to 15% significantly reduced the effectiveness of all dusts. When insecticides were combined with silica, their toxicity increased markedly. Malathion on silica (0.2%) reduced LC₅₀ values to 21.5 and 23.3 µg a.i./100 g for T. castaneum and S. oryzae, respectively, compared to 52.3 and 84.7 µg a.i./100 g on talc. Pirimiphos methyl on silica (0.1%) was the most effective, achieving LC₅₀ values of 13.4 and 15.5 µg a.i./100 g. Long-term bioassays over 25 weeks showed declining mortality rates, particularly at 15% moisture. However, pirimiphos methyl on silica maintained over 90% mortality at 12% moisture throughout the period, indicating strong residual efficacy. The results highlight the synergistic potential of combining silica with chemical insecticides and the crucial role of environmental humidity in stored grain pest management. Full article

Plodia interpunctella is a globally significant pest of stored grains, posing a major threat to food safety. To explore its cold-adaptation mechanisms, this study evaluated the physiological and developmental responses of different life stages following short-term cold acclimation at 4 °C. Results showed that cold acclimation significantly reduced the supercooling points (SCPs) of larvae and pupae, with the greatest reduction observed in the second instar larvae. Antioxidant enzyme assays revealed marked increases in the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), indicating enhanced oxidative stress resistance. Developmental durations were significantly shortened at lower temperatures in acclimated individuals, and fecundity was notably increased at 24 °C, although no significant changes were observed at higher temperatures. These findings suggest that cold acclimation improves the cold tolerance and reproductive performance of P. interpunctella under low-temperature conditions, offering insights into insect adaptability and providing theoretical support for the development of low-temperature-based pest management strategies in stored grain systems. Full article

Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) is one of the most destructive pests of stored grains worldwide. Sublethal concentrations of insecticides are known to influence insect behavior, potentially disrupting critical processes such as mating. This study investigated the effects of λ-cyhalothrin at the lethal concentration (LC) values LC₁₀ and LC₃₀ and lateralization on the mating behavior patterns of S. zeamais males. Results showed that the exposure to sublethal concentrations of λ-cyhalothrin significantly altered the copulation success rate and key time-related parameters, including mate recognition and copulation duration, while the lateralization caused significant differences in mating time-related parameters within each tested group (control, LC_10, and LC₃₀). Additionally, the λ-cyhalothrin-treated groups showed prolonged mate recognition times and required more mounting attempts to achieve mating. These findings highlight the potential of sublethal insecticide applications to control S. zeamais populations by impairing reproduction. Full article

In this study, the seeking behaviour and food acceptance of larvae of Plodia interpunctella Hübner (Lepidoptera: Pyralidae) were analysed under laboratory conditions. Larval orientation and feeding preferences were assessed using a selection arena for neonate larvae and a four-way olfactometer for third-instar larvae. Stimulants included amaranth bars with additives (honey and chocolate) and natural amaranth (toasted grain only). The results showed that amaranth volatiles influence the orientation and feeding behaviour of this polyphagous insect. A marked preference for sugar-rich foods was observed, with amaranth with honey and amaranth with chocolate being the food sources most frequently chosen by the neonate larvae. These individuals exhibited a gregarious feeding behaviour and did not engage in cannibalism. The third-instar larvae also showed a preference for sweet food but were more attracted to the amaranth–additive combination. In the four-way olfactometer bioassays, chocolate was the most frequently chosen stimulus, while cellophane did not differ significantly from air. An analysis of volatile compounds by gas chromatography mass spectrometry (GC-MS) revealed that amaranth with chocolate releases more volatile compounds (16) compared with honey (12) and natural amaranth (6), suggesting that these volatiles could possibly influence the larvae’s choice of food source. Full article

This study investigated the physiological regulatory mechanisms by which exogenous trehalose intake enhances the adaptation of the global stored-grain pest T. castaneum to high-concentration carbon dioxide (CO₂) stress. By supplementing exogenous trehalose under high-CO₂ controlled atmosphere stress, we measured the activities of key detoxification enzymes (e.g., carboxylesterase and cytochrome P450) and the levels of carbohydrate substances (e.g., glycogen, glucose, and trehalose). The results demonstrated that trehalose feeding significantly alleviated CO₂ induced mortality in T. castaneum and prolonged their survival time. In terms of detoxification metabolism, a trehalose-rich diet significantly reduced the activities of cytochrome P450 and carboxylesterase, while the glucose content in the beetles decreased markedly. These findings indicate that trehalose accumulation mitigates physiological damage caused by high-CO₂ stress in T. castaneum. Furthermore, exogenous trehalose intake did not disrupt carbohydrate metabolic homeostasis in the beetles, as trehalase activity and the levels of various carbohydrates remained relatively stable. This study elucidates the role of trehalose metabolism in T. castaneum’s adaptation to high-CO₂ environments, providing a theoretical foundation for optimizing controlled atmosphere grain storage technology and developing novel pest control strategies. Full article