Stored Wheat Research Articles

Identification and control of toxin-producing fungus in wheat grain stores using environment friendly factors

Background: The problem of mycotoxins in wheat crops can lead to health issues for humans and animals. It is very important to find safe and efficient methods to prevent the growth of toxin-producing fungi or reduce and remove them from food to prevent their risks to humans, animals, and agricultural crops. The paper focuses on finding environmentally friendly materials to protect wheat grains from toxin-secreting fungi, particularly Aspergillus niger, reducing the production of aflatoxin B1.Methods: Eight fungal genera were isolated from wheat grain samples, and the most frequent fungus was A. niger. Plant extracts were used to reduce the growth of A. niger, and the culture media was used to test the ability of A. niger fungus isolates to produce aflatoxin toxins. The media was also used to sow wheat grains for the purpose of isolating the fungi associated with them, growing the fungi, and purifying it. The culture media was poured into sterile petri dishes with a diameter of 9 cm, with three replicates for each concentration, and the comparison treatment in which an untreated food media was used. Results: The paper found that A. niger was the frequent fungus among the isolated fungal genera in wheat grain samples. The plant extracts, particularly citrullus extract, showed a clear effect in inhibiting the growth of A. niger and reduced the AFB1 toxin that it produces. The paper recommends continuous examination of stored wheat grains to determine the amount of fungal contamination and to ensure good storage conditions before receiving the grains in grain stores.Conclusion: The paper aimed to detect fungi associated with local and imported wheat grains stored in the stores of Al-Muthanna Governorate and the possibility of reducing them by using some plant extracts. Keywords: Citrullus; Phylex; Aspergillus niger; AFB1

Impact of UV-C irradiation on pests and fungi in stored wheat

The application of UVC radiation in stored wheat grains in Brazil is still very recent and the study of the parameters of this technology in stored products becomes important for the advancement in the scientific as well as technological areas. This is mainly due to the fact that it is a cheap technology that does not leave residues, and can be used to replace chemical pesticides. Thus, the objective of the present work is to evaluate the effect of UV-C radiation on the control of insect pests and fungi in wheat grains. For this purpose, wheat grains containing 20 adult insects of Sitophilus sp were irradiated with UVC light for 15 and 30 minutes at intervals of 15 days for 120 days of storage. At the end of the period, live and dead insects, mass loss and total fungal count were evaluated. Based on the analyses carried out, the use of UV-C Light has been reaffirmed as an effective microbiological control method. On the other hand, the study of its use as a method of biological control, under the conditions of the experiment in which the plant material used were wheat grains with moisture content below 10%, is not feasible since the exposure of wheat grains infested with Sitophilus sp. During the 15 and 30 minute periods, every 15 days there was no statistical difference when compared to the control group.

The effect of the interactions of water activity, and temperature on OTA, OTB, and OTα produced by Penicillium verrucosum in a mini silo of natural and inoculated wheat using CO2 production as fungal activity sentinel

Ochratoxin A (OTA) is a nephrotoxin that contaminates grains in storage. Moisture and temperature sensors give delayed responses due to their slow kinetic movement within the silo. This study examines if CO2 production could predict OTA contamination and identify storage conditions exceeding the maximum limit (5 μg/kg). The impact of water activity levels (0.70–0.90 aw), temperatures (15 and 20 °C), and storage duration on (a)Penicillium verrucosum population, (b)CO2 respiration rates (RR), and (c)ochratoxins concentrations in stored wheat was investigated. 96 samples were analysed for ochratoxins with LCMS-MS. RR was >7 times higher at wetter conditions than at drier aw levels. A positive correlation between CO2, OTA, OTB, and OTα was observed at the wettest conditions. OTA exceeded the limit at >0.80 aw (16% moisture content) with RR > 0.01 mg CO2 kg−1 h−1. The knowledge of the RR of stored grain would alert grain farmers/managers to improve grain storage management.

The influence of different abiotic conditions on the concentrations of free and conjugated deoxynivalenol and zearalenone in stored wheat

Environmental factors influence fungal growth and mycotoxin production in stored grains. However, the concentrations of free mycotoxins and their conjugates and how they are impacted by different interacting environment conditions have not been previously examined. The objectives of this study were to examine the impact of storage conditions (0.93–0.98 aw) and temperature (20–25 °C) on (a) the concentrations of deoxynivalenol and zearalenone and their respective glucosides/conjugates and (b) the concentrations of emerging mycotoxins in both naturally contaminated and irradiated wheat grains inoculated with Fusarium graminearum. Contaminated samples were analysed for multiple mycotoxins using Liquid Chromatography Tandem Mass Spectrometry (LC–MS/MS). Method validation was performed according to the acceptable performance criteria set and updated by the European Commission regulations No. 2021/808/EC. As an important conjugate of deoxynivalenol, the concentrations of deoxynivalenol-3-glucoside were significantly different from its precursor deoxynivalenol at 0.93 aw (22% moisture content- MC) at 25 °C in the naturally contaminated wheat with a ratio proportion of 56:44% respectively. The high concentrations of deoxynivalenol-3-glucoside could be influenced by the wheat’s variety and/or harvested season/fungal strain type/location. Zeralenone-14-sulfate concentrations were surprisingly three times higher than Zearalenone in the naturally contaminated wheat at 0.98 aw (26% MC) at both temperatures. Emerging mycotoxins such as moniliformin increased with temperature rise with the highest concentrations at 0.95 aw and 25 °C. These findings highlight the influence and importance of storage aw x temperature conditions on the relative presence of free vs conjugated mycotoxins which can have implications for food safety.

Biology of Sitophilus oryzae (Coleoptera) on stored Wheat Genotypes

The biology of five different genotypes of rice weevil in stored wheat was studied in the laboratory of PG Department of Botany, Jai Prakash University Chapra (Bihar). The study found that the different developmental stages of the rice weevil were longer in winter than in summer. HUW 214 recorded the lowest incubation period of 7.53 days, while HI 8498 recorded the longest incubation period of 9.68 days. HUW 214 had the lowest total larval period (23.27 days), while HI 8598 had the highest larval period (32.38 days). The total growth period was lowest in HUW 214(41.81 days) and highest in HI 8498(56.04 days).

Potential fungicidal and antiaflatoxigenic effects of cinnamon essential oils on Aspergillus flavus inhabiting the stored wheat grains

Wheat is one of the essential crops for the human and animal nutrition, however, contamination with aflatoxigenic fungi, due to the improper storage conditions and high humidity, was the main global threats. So, preventing the growth of aflatoxigenic fungi in stored wheat grains, by using different essential oils was the main objective of this work. Aspergillus flavus EFBL-MU12 PP087400, EFBL-MU23 PP087401 and EFBL-MU36 PP087403 isolates were the most potent aflatoxins producers inhabiting wheat grains. The effect of storage conditions of wheat grains “humidity, temperature, incubation period, and pH” on growth of A. flavus, was assessed by the response surface methodology using Plackett-Burman design and FCCD. The highest yield of aflatoxins EFBL-MU12 B1 and B2 by A. flavus grown on wheat grains were 145.3 and 7.6 μg/kg, respectively, at incubation temperature 35°C, 16% moisture contents, initial pH 5.0, and incubated for 14 days. The tested oils had a powerful antifungal activity for the growth and aflatoxins production by A. flavus in a concentration-dependent manner. Among these oils, cinnamon oil had the highest fungicidal activity for A. flavus at 0.125%, with about 85-90 % reduction to the aflatoxins B1 and B2, conidial pigmentation and chitin contents on wheat grains. From the SEM analysis, cinnamon oils had the most deleterious effect on A. flavus with morphological aberrations to the conidial heads, vegetative mycelia, alteration in conidiophores identity, hyphae shrank, and winding. To emphasize the effect of the essential oils on the aflatoxins producing potency of A. flavus, the molecular expression of the aflatoxins biosynthetic genes was estimated by RT-qPCR. The molecular expression of nor-1, afLR, pKsA and afLJ genes was suppressed by 94-96%, due to cinnamon oil at 0.062% compared to the control. Conclusively, from the results, cinnamon oils followed by the peppermint oils displayed the most fungicidal activity for the growth and aflatoxins production by A. flavus grown on wheat grains.

Comparative study on the repellency and chemical profiles of different chilli peppers formulations against Sitophilus oryzae L. (Coleoptera: Curculionidae) in stored wheat

The weevil Sitophilus oryzae L. (Coleoptera: Curculionidae) is the major insect pest of stored grains, including wheat. This study tested the repellency effectiveness of three formulations, including chilli dry powder (CDP), chilli ethanol extract (CEE), and chilli crude extract (CCE), from different chilli peppers of Capsicum annuum L. and Capsicum chinense Jacquin varieties (Solanaceae), against S. oryzae using a modified cup bioassay arena. Repellency responses varied significantly (P ≤ 0.001) within the three different formulations, where the CEE formulation at the concentration of 5 g (w/w) demonstrated the highest effectiveness, effectively deterring the highest number of insects (mean number of repelled insects ± SE) after 24 h of treatment across tested chilli varieties such as Guntur Sannam chilli (GSC) (15.0 ± 0.6), Kashmiri chilli (KC) (16.0 ± 0.0), and Bhut Jolokia chilli (BJC) (18.0 ± 0.6). CDP formulation closely followed, displaying notable repellency activity against the same varieties. Conversely, the CCE formulation exhibited the least effectiveness in repelling the adult weevils. Thus, the repellency activity observed was time-, concentration-, and formulation-dependent. Further, the percentage repellency (PR) assay conducted by following the area preference method demonstrated that the Bhut Jolokia chilli exhibited the highest repellency percentage (61.2%) at a concentration of 0.251 μg/cm2, by categorizing it as a class IV repellent. Gas chromatography-mass spectrometry (GC-MS) analysis detected the presence of capsaicinoids like capsaicin and dihydrocapsaicin, alongside various non-capsaicinoids such as n-hexadecanoic acid and n-pentadecylacetamide, etc., in the ethanolic fraction of chilli pepper varieties, suggesting that the observed differences in the repellency activity might be attributed to varying chemical compositions, warranting further detailed exploration in this domain. These findings provide valuable primary insights into the prospective application of chilli pepper formulations from different varieties as a repellent against S. oryzae.

Biopesticidal Potential of Indigenous Plant Extracts against Rice Weevil in Stored Wheat

Stored products are significantly affected by certain well-known stored grain pests, with Sitophilus oryzae L. (Coleoptera: Curculionidae) being one of the most destructive pests of stored products. It is a primary pest that causes substantial quantitative and qualitative losses. The present study was conducted to investigate the insecticidal efficacy of different plant extracts from four commonly grown plants in Pakistan: ginger (Zingiber officinale), neem (Azadirachta indica), clove (Syzygium aromaticum), and tobacco (Nicotiana tabacum) against S. oryzae infesting stored wheat. Crude extracts from these plants were applied to stored wheat at various dose rates (20, 40, 60, 80 mg). Adults of S. oryzae were introduced to the treated wheat and observed for mortality, repellency, and grain damage. The results of the study indicated that the maximum mortality of S. oryzae (99.17%) was recorded due to the application of crude extract of Z. officinale, while the minimum mortality of S. oryzae (67.50%) was recorded due to the crude extract of N. tabacum at an 80 mg dose rate after a 10-day exposure interval. The maximum grain damage due to S. oryzae (0.19%) was observed in N. tabacum treated crude extract at an 80 mg dose rate, while the minimum grain damage due to S. oryzae (0.04%) was observed in Z. officinale treated crude extract at an 80 mg dose rate. Z. officinale also exhibited the maximum repellent effect on S. oryzae (95.77%). This study concluded that Z. officinale emerged as a potent, readily available biopesticide against S. oryzae, surpassing current alternatives with near-eradication efficacy, minimal grain damage, and a proactive repellent effect, paving the way for sustainable and eco-friendly pest management. Further research is needed to optimize extraction methods, dosage recommendations, and assess long-term effects on grain quality and storage stability.

Predicting early mycotoxin contamination in stored wheat using machine learning

With continued global population growth and current rate of climate change, grain loss during storage remains a major contributor to postharvest losses of wheat (Triticum aestivum L.). Infection with mycotoxin leads to degradation or even discarding of stored grain, causing economic losses and risks to food security. Deep learning models have been used in the agricultural domain for detecting prevalent diseases or contamination; however, data scarcity remains a critical bottleneck for rapid implementation of computer vision in this field. Herein, a compact convolutional transformer (CCT)–based model was applied to classify contaminated wheat by deoxynivalenol (DON) and aflatoxins (AFB1, AFB2, AFG1, and AFG2), which was divided into three main classes: healthy, incipient, and contaminated. The classification was performed based on elevated CO2 respiration rate (≥31.20 ± 0.62 mg CO2 kg−1 h−1) and visual appearance of mold formation in initial and severe stage since the start the storage experiment. The proposed CCT model achieved an accuracy of 83.33%, with the contaminated class demonstrating the highest performance metrics, including precision (1.0), recall (0.90), and F1-score (0.95), followed by the healthy and incipient classes. At the same time, explicit classification between the healthy and incipient classes deserves further improvement because it is highly relevant for the timely detection of spoilage and prevention of proliferation of mycotoxins in stored wheat.

Laboratory Study of Repellent Property of Bhut Jolokia Chilli against Sitophilus oryzae (Coleoptera: Curculionidae) in Stored Wheat

Abstract This study investigated the repellent property of ‘Bhut Jolokia’ chilli pepper, a Capsicum chinense Jacquin cultivar, against the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), in stored wheat, Triticum aestivum L., in laboratory assays using a modified cup bioassay apparatus. Contact and fumigation repellency assays were conducted with the Bhut Jolokia chilli dry powder at concentrations of 3 and 5% (w/w) of the total weight of grain and the Bhut Jolokia chilli ethanol extract at volumes of 3 and 5 ml. In the contact repellency test, the number (mean ± SE) of test insects repelled (7.90 ± 0.23) increased with increasing concentration (5%) and time interval (24 h), whereas in the fumigation repellency test, the mean number of repelled insects increased (8.2 ± 0.2) with increasing volume (5 ml) and decreased (3.80 ± 0.13) with increasing time interval (60 min). Gas chromatography–mass spectrometry (GC-MS) analysis identified that the active compounds present in the Bhut Jolokia chilli ethanol extract were the capsaicinoids capsaicin (21.50%) and dihydrocapsaicin (4.44%) and the noncapsaicinoids n-hexadecanoic acid (29.34%), n-pentadecylacetamide (12.92%), and others. Our findings provide a preliminary assessment of the repellent property of Bhut Jolokia chilli against S. oryzae in stored wheat under laboratory conditions and serve as an impetus for continued research.

Application of Two Ocimum Species Powders in the Control of Red Flour Beetles, Tribolium castaneum Herbst (Coleoptera: Tenebronidae), during Wheat Grain Storage

Pest insects on stored goods are a problem everywhere in the world because they lower grain yields and quality. This has the impact of creating a significant danger to global food security, which could negatively affect people's well-being. In the human endeavor to lessen the threat caused by these insects, the use of synthetic chemical insecticides has unfavorable effects. Recently, there has been advancement in the use of botanicals and agricultural wastes in the control of these pests. This research investigated the effects of Ocimum gratissimum (African basil) and O. basilicum (common basil) powders against Tribolium castaneum infesting wheat grains in storage. Powders were tested singly and mixed at doses of 0.2, 0.4, 0.6, 0.8 and 1.0 g per 20 g of wheat grains. The following parameters were determined: adult mortality, adult emergence rates, seed damage %, weight loss %, and beetle perforation index. The data showed that two Ocimum powders were efficacious and their effectiveness increased with increasing the dosage and also the exposure time. The population of adult T. castaneum on treated wheat grains was significantly (p < 0.05) decreased by the two tested Ocimum species powders. After 24 hours of treatment, 1.0 g of O. basilicum powder caused 50% mortality of adult T. castaneum. However, the combination of O. gratissimum and O. basilicum powders caused 40% of beetles' mortality. On the other hand, O. gratissimum powder was the least toxic on adult T. castaneum with 30% only mortality. The lethal doses of both tested powders and their combination required to cause 50% mortality of the T. castaneum population after the first day of exposure were 1.09, 1.44, and 1.45 g, respectively. While, the lethal dose required to cause 90% mortality (LD90) was 4.24, 8.44, and 5.38 g after the first day post exposure. This study demonstrated the toxicity of O. gratissimum and O. basilicum powders on the survival of T. castaneum on wheat grains. The least deadly dose was recorded on O. gratissimum. Therefore, it is recommended that poor resource farmers and food vendors use Ocimum powder as a biocontrol to manage the red-rust flour beetle in stored wheat grains.

Insecticidal activity of crude olive pomace oils from Kabylia (Algeria) against the infestation of Rhyzopertha dominica (F.) and Sitophilus oryzae (L.) in stored wheat grains

The insecticidal effect of four crude olive pomace oils extracted from pomace collected from four localities of Kabylia, refined olive pomace oil and extra virgin olive oil were assessed under laboratory conditions for the control of adults of Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrychidae)) and Sitophilus oryzae (Linnaeus, 1763) (Coleoptera: Curculionidae). The doses used ranged from 0.1 to 0.4 ml/25 g of durum and soft wheat seeds. In addition, the quality indices and the fatty acid composition of these oils were evaluated. The results show that the legal quality indices were well within the legal limits for crude olive-pomace oil (COP), refined pomace oil (ROP) and extra-virgin olive oil (EVO) categories. The effectiveness of these vegetable oils is highly dependent on the insect species, the dose rate, the exposure time and the type of oil tested The main fatty acids from all samples tested, were oleic (61.89–79.25%), palmitic (8.34–15.71%) and linoleic (8.17–16.52%) acids. For both species and substrates tested, mortality is dose and time of exposure dependent. The highest dose (0.4 ml/25 g) causes ≥ 63.75% mortality, after 24 h of exposure. Comparison of LD50 (ml/25 g) indicates that olive oil was generally more toxic than crude and refined pomace oils, for both insects and substrates, values varies from 0.005 to 0.189. The most sensitive insect was S. oryzae for most vegetable oils tested. Likewise, oils significantly reduced the F1 offspring of both insects and seed weight losses. No progeny were observed in the two pests at the highest dose, and therefore no weight loss was recorded. The results also revealed that the six oils affect the germination capacity of durum and soft wheat seeds when the dosage is increased. The results collected remain encouraging for the recommendation of natural substances as part of integrated pest management programmes against insect pests of stored grains.

Pesticide residues in stored wheat and their action on Sitophilus oryzae and Rhyzopertha dominica

The concern over supplying safe foods and discarding food lots with agrochemical residues over the legal limits has been the target of alerts from various agencies. Products derived from wheat are widely consumed in Brazil, and thus studies that aim at detecting agrochemical residues in this cereal grain and their risks are of utmost importance. The aims of this study were to evaluate the presence of agrochemical residues in wheat stored in a silo in Rio Grande do Sul and verify if there was residual action of the insecticides detected in the wheat. The first experiment consisted of multiresidue analyses of agrochemicals over a period of 10 months of storage. The second consisted of infesting samples from the previous experiment with Sitophilus oryzae and Rhyzopertha dominica to evaluate mortality. Nine agrochemicals were detected in the wheat, of which six were below the maximum limit of residues and three were above, according to Brazilian legislation. There was 100% mortality of Sitophilus oryzae after 96 h of exposure of this insect to the grain in all the samples evaluated, indicating that the residues of insecticide were still active even after the withholding period. No mortality was observed for Rhyzopertha dominica in the samples analyzed.

A winning formula: sustainable control of three stored-product insects through paired combinations of entomopathogenic fungus, diatomaceous earth, and lambda-cyhalothrin.

This research aimed to assess the effectiveness of Metarhizium robertsii, diatomaceous earth (Protect-It), and lambda-cyhalothrin, for the long-term protection of stored wheat against three destructive grain insect pests, Rhyzopertha dominica, Tribolium castaneum, and Trogoderma granarium. Different treatments were applied, both alone and in paired combinations in laboratory and persistence trials. Single treatments exhibited significantly lower mortality rates in comparison to the paired treatments for all tested insect species. Among the single treatments, lambda-cyhalothrin (Lamb) resulted in significantly higher mortality rates in laboratory trials, followed by diatomaceous earth (DE) and M. robertsii (Mr), with insignificant differences between Mr and DE. Evidently, DE exhibited the highest persistence after 120days of storage for all insect species and initial exposures, although variations in mortality rates among treatments were mostly insignificant. Overall, the most effective treatment in terms of mortality in laboratory, and persistence trials, and progeny production was DE + Lamb, followed by Mr + Lamb, and Mr + DE for all tested insect species. In general, the most susceptible insect species was R. dominica, followed by T. castaneum and T. granarium. This research highlights the effectiveness of M. robertsii, DE, and lambda-cyhalothrin in providing prolonged protection of stored wheat against all the examined grain insect species.

Sustainable Solutions for Wheat Grain Protection: Evaluation of Inert Materials against Rice Weevil (Sitophilus oryzae L.)

This study investigated the potential of three readily available inert materials – apple wood ash, kaolin, and silica – for controlling the rice weevil (Sitophilus oryzae L.), a pest of stored grains. We evaluated their efficacy at three concentrations (2%, 4%, and 8%) against adult weevils over an 8-day treatment period. Apple wood ash emerged as the most potent material, achieving a remarkable 100% cumulative mortality rate on the eighth day at the highest concentration, statistically exceeding the performance of kaolin (90%) and silica (40%). The untreated control group exhibited a significantly lower mortality rate of 6.66%. Beyond immediate mortality, both apple wood ash and kaolin demonstrated outstanding ability to protect wheat grains from infestation damage. Treatment at 8% significantly reduced the emergence of new adult weevils, minimized grain damage percentage, and mitigated of weight loss. Apple wood ash displayed remarkable effectiveness, with protection values exceeding 95% for all three parameters (emergence: 96.02%, damage: 89.09%, weight loss: 91.68%). Kaolin also performed well, achieving close to 90% protection in all categories (emergence: 89.55%, damage: 84.13%, weight loss: 88.24%). Conversely, silica displayed a significantly lower efficacy, with protection values hovering around 55% for all parameters (emergence: 56.40%, damage: 51.48%, weight loss: 56.64%). These findings highlight the promising potential of readily available inert materials, particularly apple wood ash and kaolin, as eco-friendly alternatives to synthetic insecticides for managing rice weevil populations in stored wheat. Their integration into pest management programs offers a sustainable and effective approach to minimizing grain losses and preserving food security.

GC-IMS determination of volatile organic compounds as potential indicators of wheat germination rate

The objective of this research was to investigate the correlation between volatile organic compounds (VOCs) and the germination rate of stored wheat, as well as to identify the potential markers for predicting the germination rate. The findings of this study are expected to contribute to the advancement of a non-destructive and rapid method for evaluating the quality of wheat storage, thereby establishing a theoretical foundation for further research in this area. Gas chromatography-ion mobility spectrometry (GC-IMS) was utilized to analyze the VOCs of wheat samples subjected to accelerated storage condition at 40 °C, RH 65%, as well as natural storage condition at room temperature. A total of 68 and 79 VOCs were detected under accelerated and natural storage conditions, respectively. The germination rate of wheat was found to decreased significantly with prolonged storage time under both storage conditions. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were utilized to differentiate wheat samples stored for varying durations. Furthermore, correlation analysis revealed that 31 VOCs exhibited a significant correlation (p < 0.05) with the germination rate. Through multiple linear stepwise regression analysis, four VOCs—namely isoamyl butyrate, (Z)-3-nonen-1-ol, 1-propanol, and Propanal—were identified as potential markers. Subsequently, a prediction model was constructed using these markers. The results of this study demonstrate that these VOCs can serve as indicators for predicting the germination rate, thus facilitating the evaluation of the germination ability and quality of stored wheat. This research holds implications for enhancing the efficiency of wheat storage management and ensuring food security.

Efficacy of the entomopathogenic fungus, Metarhizium anisoplae, against Khapra beetle Trogoderma granarium (Coleoptera: Dermestidae) under laboratory conditions

The khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is an important pest of stored wheat worldwide. This study assessed the efficacy of two isolates of M. anisoplae (commercial and local isolates). Different conidial concentrations (1×108, 1×106, 1×104) conidia/ml-1 and fungal filtrate (100, 75, 50) % of M. anisoplae were evaluated. In both fungal isolates, corrected mortality of T. granarium after exposure varied according to fungal concentrations conidial concentration of conidia/ml-1, and the fungal filtrate at a concentration of 75% caused the highest mortality rates. In addition, mortality rates were significantly varied according to the beetle's developmental stage. Both isolates of M. anisoplae caused between 41 and 67.6 % reduction in total fecundity of the female adults. The results demonstrate no significant differences between the local isolate of M. anisoplae and commercial formulation (Met 52 EC). Further studies under commercial storage conditions are required. Keywords: Insects storage pests, biological control, Entomopathogenic fungi

Efficacy of pulegone, and eugenol alone and in combination with synthetic insecticides for the management of three stored product beetle pests

The rising public concern over the safety and environmental impact of synthetic insecticides, along with the evolution of resistance, are driving entomologists to search for new pest control alternatives. Essential oils and their constituents have been proposed as the most promising alternatives due to their wide spectrum of biological activity and synergistic interaction with traditional insecticides. Therefore, the present work evaluated the toxicity of a monoterpene, pulegone (250 and 500 mg/kg), and a phenylpropene, eugenol (250 and 500 mg/kg), alone and in combination with deltamethrin (0.1 and 0.25 mg/kg), pirimiphos-methyl (2.5 and 5.0 mg/kg), and thiamethoxam (0.1 and 0.5 mg/kg) against Rhyzopertha dominica, Sitophilus oryzae, and Tribolium castaneum on wheat grains. Pulegone exerted significant toxicity at 250 and 500 mg/kg against the three beetle species, with complete mortality after 14 days of exposure, complete inhibition of progeny production, and complete protection of treated wheat grain after 75 days of treatment. While eugenol at the higher application rate tested (500 mg/kg) caused 68.3, 31.7, and 5.0 % mortality in adults of R. dominica, S. oryzae, and T. castaneum, with reduction in progeny production of 81.3, 67.7, and 79.7%, respectively. In combination treatments, pulegone reduced toxicity against tested insect species when mixed with the three insecticides, indicating an antagonistic effect. While treated wheat grains with binary mixtures of eugenol (500 mg/kg) with deltamethrin, pirimiphos-methyl, and thiamethoxam enhanced their toxicity, resulting in higher mortality rates, fewer emerged adults, and a lower loss in weight of wheat grains than those obtained in individual treatments. Based on these findings, we suggest that pulegone and eugenol might be viable options for usage in protecting stored wheat against the tested insect species. Additionally, eugenol has the potential to enhance the toxicity of synthetic insecticides, which could reduce their application rates and manage the resistance to these insecticides.

EVALUATION OF DIFFERENT STRAINS OF ENTMOPATHOGENIC FUNGI AS POTENTIAL AGENTS FOR THE MANAGEMENT OF TRIBOLIUM CASTANEUM

The global economic significance of wheat (Triticum aestivum) is undeniable, as it serves as a primary food source for 40% of the human population. T. castaneum, a notable economic pest, particularly impacts stored wheat grains and flour. In the pursuit of sustainable pest control, entomopathogenic fungi (EPF) have emerged as advanced microorganisms, providing viable alternatives to harmful synthetic chemical insecticides. This study employed four fungal strains—Beauveria bassiana, Isaria cateniannulata, Trichoderma harzianum, and Metarhizium attenuatum—against mixed adult populations of T. castaneum under controlled laboratory conditions. Different concentrations (1×10², 1×10⁴, 1×10⁶, 1×10⁸, 1×10¹⁰ cfu/ml) for each fungus were employed, and mortality data, LC50, and LT50 were recorded at post-exposure intervals of 4, 6, 8, and 10 days. The application method involved using the fungus through a filter paper dip, and red flour beetle adults were introduced to wheat grains. The highest mortality, observed at the concentration of 1×10¹⁰ cfu/ml, was 80% for both M. attenuatum and B. bassiana. Conversely, the lowest mortality, recorded at the concentration of 1×10² cfu/ml, was 64% for I. cateniannulata, while T. harzianum demonstrated 70% mortality at 1×10¹⁰ cfu/ml. The utilization of entomopathogenic fungi for insect control represents an emerging strategy. B. bassiana and M. attenuatum emerge as promising alternatives for managing T. castaneum in stored grains.

Formulation of pectin-Citrus aurantium essential oil-based packaging film and assessment of insecticidal performances against Rhyzopertha dominica on stored wheat

In stored wheat products, Rhyzopertha dominica (F) (Coleoptera: Bostrichidae) is an important pest that results in significant economic losses. Insect physiology and behavior can be affected by bioactive compounds extracted from plant wastes, which are important tools for developing bioincesticides. The purpose of this study is to develop an insecticidal packaging film based on pectin and essential oil (EO) extracted from Citrus aurantium (L., 1753) fruit peels.The encapsulation efficiency (EE) and cumulative release (CR) of C. aurantium EO into pectin film were determined. Further, Film packaging was tested against Rhyzopertha dominica adults reared on Karim and Khiar durum wheat (Tritichum durum Desf.) varieties. The fumigant toxicity was assessed after 10, 20, 30 and 40 days of storage. Moreover, emergence inhibition of R. dominica adults was determined. In addition, germination rate, weight loss and grain damage were examined.Results revealed that the lethal concentration that killed 50 % of the exposed adults developed into karim and khiar varieties were 278.45 and 688.79 µL/L air, respectively. Moreover, high encapsulation efficiency of C. aurantium essential oil into pectin film with an EE = 80.6 %. Moreover, pectin: EO film achieved complete (100 %) mortality and emergence inhibition of R. dominica adults for all storage periods. Also, pectin: EO film represent the better treatment which preserve the quality and quantity of wheat grains as well as grain damage, weight loss and germination rate. To concludepectin- C. aurantium EO film showed a significant fumigant effect against R. dominica adults and the emergence of their descendants after different storage periods and could be recommended as an active ingredient for a natural packaging against stored product insects.