Search Results (74)

Phosphine resistance represents a major challenge for stored product protection worldwide. In this study, we evaluated populations of Oryzaephilus surinamensis, Rhyzopertha dominica, and Cryptolestes ferrugineus collected from different regions using three diagnostic protocols: (i) the FAO test (30 ppm for 20 h); (ii) a dose–response bioassay (50–1000 ppm for 3 d); (iii) the Phosphine Tolerance Test (3000 ppm for up to 270 min). Results indicated that while several O. surinamensis populations remained susceptible, all tested populations of R. dominica and C. ferrugineus were resistant. The three protocols produced comparable outcomes, supporting their reliability for diagnosing resistant populations. This is the first study to simultaneously compare three diagnostic approaches across multiple beetle species, providing the basis for a harmonized global diagnostic framework. These findings underscore the need for continued monitoring and highlight the importance of standardized tools for resistance management. Full article

The present study highlights the critical role of surface type, insect species, and exposure duration in determining the efficacy of surface-applied insecticides in stored-product pest management. Four insecticides were sprayed and evaluated on different surfaces (concrete, metallic, plastic, and ceramic) against two beetles: the red flour beetle and the tobacco beetle. Alpha-cypermethrin and spinosad exhibited rapid and high efficacy, particularly on non-porous surfaces such as metal and ceramic, whereas pirimiphos-methyl was less effective initially and required extended exposure to achieve complete mortality, especially against Tribolium castaneum. In contrast, Lasioderma serricorne showed greater susceptibility across all insecticides and surfaces. Spinosad maintained high efficacy across all surface types, suggesting broader applicability under variable conditions. The reduced performance of insecticides on concrete surfaces underscores the influence of substrate porosity on insecticide bioavailability. Additionally, the observed delayed mortality effect in all treatments indicates that even brief exposure can result in lethal outcomes, emphasizing the long-term potential of these applications. These findings underscore the need for surface-specific application strategies and support the integration of surface treatments into comprehensive pest management programs. Further research is warranted under simulated field conditions to assess residual efficacy over time and in the presence of food, thereby enhancing the relevance of laboratory findings to real-world storage environments. Full article

Effective stored-grain insect pest detection is crucial in grain storage management to prevent economic losses and ensure food security throughout production and supply chains. Existing detection methods suffer from issues such as high labor costs, environmental interference, high equipment costs, and inconsistent performance. To address these limitations, we proposed PDA-YOLO, an improved stored-grain insect pest detection algorithm based on YOLO11n which integrates three key modules: PoolFormer_C3k2 (PF_C3k2) for efficient local feature extraction, Attention-based Intra-Scale Feature Interaction (AIFI) for enhanced global context awareness, and Dynamic Multi-scale Aware Edge (DMAE) for precise boundary detection of small targets. Trained and tested on 6200 images covering five common stored-grain insect pests (Lesser Grain Borer, Red Flour Beetle, Indian Meal Moth, Maize Weevil, and Angoumois Grain Moth), PDA-YOLO achieved an mAP@0.5 of 96.6%, mAP@0.5:0.95 of 60.4%, and F1 score of 93.5%, with a computational cost of only 6.9 G and mean detection time of 9.9 ms per image. These results demonstrate the advantages over mainstream detection algorithms, balancing accuracy, computational efficiency, and real-time performance. PDA-YOLO provides a reference for pest detection in intelligent grain storage management. Full article

Contact insecticides are classified into two categories: as grain protectants, which are applied directly on grains, and as surface treatments, which are applied on cracks and crevices. The aim of this study was to evaluate the long-term residual efficacy of these insecticides across different surfaces and target species. Thus, we investigated the efficacy of three insecticidal formulations, spinosad, alpha-cypermethrin, and pirimiphos-methyl against stored product beetles on different surfaces (concrete, metallic, plastic, and ceramic). Adults of Tribolium castaneum, Sitophilus granarius, and Lasioderma serricorne were used in the experiments. Bioassays were carried out during a six-month period, with mortality measured after 3, 7, 14, and 21 days after exposure. Among the different insecticides tested, spinosad was the least effective against T. castaneum, especially on concrete, where mortality had decreased to zero by Month 2, whereas in most of the cases, close to 100% was recorded. Regarding S. granarius, pirimiphos-methyl and spinosad remained effective on ceramic and metallic surfaces for a six-month period, whereas alpha-cypermethrin had the lowest mortality rate. For L. serricorne, spinosad caused high mortality levels, whereas pirimiphos-methyl was the least effective after Month 4. Based on our finding, among the tested insecticides, spinosad had the long-term residual effect on stored product protection. Full article

The foreign grain beetle, Ahasverus advena (Waltl) (Coleoptera: Silvanidae), has been reported from 110 countries on more than 162 commodities, more than 35 types of facilities, and 14 other habitats such as compost heaps and haystacks or manure. Compost heaps, haystacks, and manure heated by fermentation may allow overwintering in cold climates, making them important sources of infestation. From these sources the A. advena can fly and infest grain storage and processing facilities. A. advena has been found in empty grain storage bins, is often found in wheat immediately after harvest, and is most abundant early in wheat storage. Larvae and adults of A. advena are well adapted to feeding on several species of fungi and have higher chitinase levels and greater tolerance for fungal aflatoxins than other species. A. advena lay more eggs on the fungal species on which their offspring can develop most successfully. They are attracted to fungal odors and high moisture commodities and have the capability to disseminate grain fungi that cause hot spots within the grain mass. The presence of fungus beetles is indicative of poor storage conditions. A. advena is capable of feeding on some commodities and is a predator that may have a potential role in biological control. They are strong fliers but are distributed extensively with the movement of commodities in the marketing system. In countries with a zero tolerance for insects, their presence is sufficient for rejection of a load and associated economic losses. In other countries, contamination by A. advena is a problem, and in India, it is listed as a quarantine pest. Extension agents have had many requests for the identification of this species, and two other species of the same genus have been found in stored products. Some information is available for the effectiveness of nine pest management methods for A. advena. Full article

Background/Objectives: Phosphine resistance in insects involves a complex interplay of genetic and physiological factors, which are often poorly understood. Resistance to high concentrations of phosphine worldwide poses a formidable challenge for stored-product pest management and affects global food security. Understanding the genetic basis of phosphine resistance in the red flour beetle, Tribolium castaneum, is urgent because of the species’ status as a notorious insect pest of stored grains and their resistance to major classes of insecticides. In this study, we take advantage of T. castaneum as a model species for biological and genetic studies. Methods: To tease apart genetic mutations and the differential expression of genes responding to phosphine intoxication, we set up 16 different exposure tests to compare the effects of phosphine dose, exposure time, and sampling time on gene expression in phosphine-susceptible and -resistant T. castaneum adults. Results: We examined the enrichment of gene ontology terms in genes that were differentially expressed and found that the data further distinguished differences in gene expression by insect strain, phosphine dose, exposure time, and recovery from phosphine exposure. The gene-encoding cytochrome P450 9e2 was expressed more in phosphine-resistant compared to phosphine-susceptible insects under all treatment conditions and was significantly higher in expression in resistant insects that were sampled after short or long phosphine exposures. Therefore, this gene may serve as a new phosphine resistance marker in T. castaneum and can further be utilized as a diagnostic tool for resistance detection. Conclusions: These data are important to understand the complex molecular changes in insects that have reduced sensitivity to phosphine to develop new monitoring and resistance prevention strategies. Full article

Chlorobenzene is an industrial chemical with relatively high vapor pressure and has been used in the past to produce pesticide DDT (Dichlorodiphenyltrichloroethane). In this study, chlorobenzene was demonstrated to be an effective fumigant against two stored product insects: the confused flour beetle (Tribolium confusum) and rice weevil (Sitophilus oryzae). In small-scale fumigations in 1.9 L glass jars, the complete control of adults of both the confused flour beetle and rice weevil was achieved in 24 h at a dose of 150 μL/L at 21 °C. LC₉₅ values of chlorobenzene vapor concentration for adults of the confused flour beetle and rice weevil were estimated to be 1121 and 1114 ppm, respectively. In large-scale fumigations in a 60 L chamber, all life stages of the confused flour beetle and rice weevil in 20 kg of corn were fumigated for 24 h with 30 mL (500 μL/L) chlorobenzene at 21 °C. The complete control of adults and immature stages of the confused flour beetle was achieved. For the rice weevil, adults had 100% mortality, and immature life stages had 97.8% mortality. These results demonstrated that chlorobenzene is effective as a fumigant against stored product insects, and it is technically feasible to conduct large-scale fumigations for postharvest pest control on stored products. Full article

Phosphine is a widely utilized fumigant insecticide in stored-product facilities; however, its excessive application and improper usage have contributed to the emergence of resistance in insect populations. Although phosphine resistance is globally recognized, limited studies address its effects across different developmental stages. This research investigates the efficacy of phosphine on the eggs of major stored-product pests, including Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), Tribolium castaneum, and T. confusum (Coleoptera: Tenebrionidae), focusing on strains with varying levels of phosphine susceptibility. Egg hatching rates were analyzed following exposure to phosphine concentrations ranging from 50 to 1000 ppm for durations of 1 to 7 days. Predictive models were constructed to correlate phosphine concentration and exposure time, facilitating the determination of optimal pest control strategies. The findings reveal significant differences in efficacy among species and strains, with eggs from susceptible strains experiencing complete hatch failure at 50 ppm, while resistant strains showed higher tolerance. Lethal time (LT50 and LT99) values were determined, with LT99 ranging from 6.91 to 12.95 days at 50 ppm, highlighting species-specific and age-related differences in phosphine susceptibility. Lethal concentration (LC₅₀ and LC₉₉) values could only be estimated for T. castaneum, with LC₉₉ for 1-day-old eggs ranging from 773.67 ppm to 923.03 ppm after 2.5 days of exposure. Furthermore, egg age influenced susceptibility, with 2-day-old eggs exhibiting greater mortality compared to 1-day-old eggs. This study underscores the critical role of phosphine concentration, exposure duration, and developmental stage in resistance management, providing valuable insights for enhancing fumigation protocols and improving the control of stored-product pests. Full article

The ability of entomopathogenic fungi, such as Beauveria bassiana, to infect insects by penetrating their cuticle is well documented. However, some insects have evolved mechanisms to combat fungal infections. The red flour beetle (Tribolium castaneum), a major pest causing significant economic losses in stored product environments globally, embeds antifungal compounds within its cuticle as a protective barrier. Previous reports have addressed the contributions of non-cuticular infection routes, noting an increase in mortality in beetles fed with conidia. In this study, we further explore the progression and dynamics of oral exposure in the gut of T. castaneum after feeding with an encapsulated B. bassiana conidia formulation. First, we characterized the formulation surface using atomic force microscopy, observing no significant topological differences between capsules containing and not containing conidia. Confocal microscopy confirmed uniform conidia distribution within the hydrogel matrix. Then, larvae and adult insects fed with the conidia-encapsulated formulation exhibited B. bassiana distributed throughout the alimentary canal, with a higher presence of conidia before the pyloric chamber. More conidia were found in the larval midgut and hindgut compared to adults, but no germinated conidia were observed in the epithelium. These results suggest that the presence of conidia obstructs the gut, impairing the insect’s ability to ingest, process, and absorb nutrients. This disruption may weaken the host, increasing its susceptibility to infections and, ultimately, leading to death. By providing the first direct observation of fungal conidia within the alimentary canal of T. castaneum, this study highlights a novel aspect of fungal–host interaction and opens new avenues for advancing fungal-based pest control strategies by exploiting stage-specific vulnerabilities. Full article

Floor traps were placed in a feed mill in Greece for a period of approx. 13 months to illustrate the relative abundance and distribution of the stored product insects found. More than 20 taxa were found, with most of them belonging to Coleoptera. The most abundant species found were the rice weevil, Sitophilus oryzae (L.), and the granary weevil, Sitophilus granarius (L.), which are common primary colonizers of grains, and the confused flour beetle, Tribolium confusum Jacquelin du Val, and the red flour beetle, Tribolium castaneum (Herbst), which are secondary colonizers that usually occur in processed amylaceous commodities. Interestingly, the highest population densities of all four species were recorded during the same period, with the secondary colonizers slightly preceding the primary colonizers. Although competition among these species has been recorded in previous studies, we found that these four species could coexist during the entire trapping period in the same sampling units, which indicates possible spatial segregation and different colonization patterns in space and time. Our results demonstrate that trapping in storage and processing facilities is an essential component of decision-making regarding stored product pest management strategies in localized applications, and can drastically reduce the need for treating the entire facility. Full article

Loss of stored plant products due to insect infestation is a problem that is likely to increase with global warming. Improved storage under hermetic conditions in oxygen deficiency can prevent or control infestation and preserve product quality. Oxygen levels in hermetic storage decrease due to different factors, one of which is the oxygen consumption of the insects present. Experiments were carried out using varying numbers (25, 50, or 200) of all developmental stages of the grain weevil Sitophilus granarius L. (eggs, larvae, pupae, and adult beetles) caged and placed in sealed 30-L containers containing 22 kg of wheat for at least 21 weeks. Oxygen levels were measured at regular intervals. The oxygen consumption depended on the number of insects and went below the critical threshold of 3% for S. granarius survival in most of the trials. Some surviving beetles were observed at the end of the hermetic experiments and 12 weeks afterwards during control for progeny, when oxygen levels did not fall below the critical threshold or the low level could not be maintained for a sufficient time. Monitoring oxygen levels in hermetic storage is therefore essential to ensure safe storage over long periods. Full article

Background: Food security is an increasingly pressing global issue, and by 2050, food production will not be sufficient to feed the growing population. Part of global food insecurity can be attributed to post-harvest losses, including quantity and quality losses caused by stored-product pests like insects. It is thus timely to find management strategies to mitigate these losses and counteract food insecurity. The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), a global stored-product pest with a wide range of food sources, was used in this study to assess repellency to a selection of essential oils. Methods: Multiple behaviorally relevant methods were used to determine the efficacy of the essential oils in assays to pinpoint the most promising repellents. Experiments were used to assess individual and group behaviors with or without airflow and examined the behavioral variation in distance moved and the time spent away from the oil. Results: It was found that exposure to essential oils and conditions of experimentation considerably influenced T. castaneum’s behavioral response, but a clear candidate for repellency could not be chosen based on the collected data. Conclusions: Follow-up research is needed to pinpoint repellents for integrated pest management practices to protect grains from stored-product pests and to justify their use in and around commodities. Full article

The skin beetle Reesa vespulae is regularly found beyond North America where it originated. The larvae cause considerable concern in museums, as they damage hides or furs in addition to being a special source of damage to collections of dried plants in herbaria or collections of insects and other zoological specimens. Reesa vespulae arrived in Europe in the mid-20th century and was associated mostly with stored food products, but over time, it has become recognised as a museum pest. Although it is still uncommon and may only be observed in a small fraction of museums, when the insect is found in large numbers, it can cause problems. Catches from blunder traps in Austrian museums and from an online database in the UK were used to track changing concern over the insect. As a single female beetle can continue to reproduce because the species is parthenogenetic, its presence can persist over long periods of time. Although small populations in museums are typically found in the adult form, the larval forms are more common where a site is infested by high numbers, perhaps because the larvae and adults must range more widely for food. Although R. vespulae can be controlled using pesticides, it is also possible to kill the larvae within infested materials through freezing or anoxia. Full article

We evaluated the persistence and efficacy of two different, in granulometry and content of diatoms, diatomaceous earth (DE) formulations (i.e., DE5 and DE6), against two major beetle species of stored products, i.e., Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). The formulations were applied as powders in soft wheat and maize in two doses of 500 and 1000 mg kg⁻¹ (ppm). Samples of the treated grains were taken on the day of application and every 30 days until completion of the six-month period of storage. Adults of S. oryzae and R. dominica were exposed to the treated grains at 25 °C and 55% relative humidity, and the mortality was measured after 7, 14, and 21 days of exposure. Rhyzopertha dominica survival was not affected by any combination of DE formulation, dose, and commodity. Contrariwise, the DEs caused significant adult mortality of S. oryzae, in most of the cases tested. We observed that DE6 was equally effective in both wheat and maize, and no considerable variations were observed in S. oryzae mortality during the 6-month experimental period. Furthermore, DE6 was more effective against S. oryzae than DE5, a difference that could have potentially contributed to the variations in the diatom granulometry between these two DEs. Thus, a DE treatment of 1000 ppm was shown to provide long-term protection of wheat and maize against S. oryzae, but this is strongly dependent on the DE formulation, commodity, and insect species. Overall, such natural resource-based inert silicaceous deposits could be used with success in stored-product protection with only some minor modifications, such as sieving and drying of the raw deposit. Full article

Food storage has been important since the dawn of agriculture and human settlement. Insect pests cause major losses to food grains during storage and production. Essential oils are good alternatives for chemical insecticides for the management of storage pests. Red bottlebrush, Callistemon lanceolatus, is a flowering plant of the Myrtaceae family. This research work aimed to extract the oil from bottlebrush leaves, and chemically characterize and assess their repellent and insecticidal properties against the cowpea seed beetle, Callasobruchus maculatus (F.) (Coleoptera: Chrysomelidae), cigarette beetle, Lasioderma serricorne (F.) (Coleoptera: Ptinidae), and red flour beetle, Tribolium castaneum (Herbst.) (Coleoptera: Tenebrionidae), for the first time. The essential oil yielded by hydro-distillation of bottlebrush leaves was 1.02 ± 0.01%. GC-MS analysis determined the chemical composition of the volatile oil comprised 1,8-cineole (19.17%), α-terpineol (11.51%), α-pinene (10.28%), and α-Phellandrene (9.55%). The C. lanceolatus leaf oil showed potent repellence, contact toxicity, and fumigation toxic effects. In the contact toxicity assay, at 24 h, the LC₅₀ values were 1.35, 0.52, and 0.58 mg/cm² for the red flour beetle, cigarette beetle, and cowpea seed beetle, respectively. Likewise, in the fumigation assay observed after 24 h, LC₅₀ values of 22.60, 5.48, and 1.43 µL/L air were demonstrated for the red flour beetle, cigarette beetle, and cowpea seed beetle, respectively. Additionally, there was no significance found by a phytotoxicity assay when the paddy seeds were exposed to C. lanceolatus oil. The results show that the volatile oils from red bottlebrush leaves have the potential to be applied as a biopesticide. Therefore, C. lanceolatus leaf oil can be utilized as a bio-insecticide to control stored product insects. Full article