Search

Sulfur dioxide (SO2) fumigation was studied in laboratory to determine its potential as an alternative treatment for postharvest control of stored product insects, confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), and rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Three-hour fumigations with 0.1%–2.0% SO2 were conducted against eggs, immature stages, and adults of the 2 insects at 20 °C. Effective control of both insects was achieved. However, there were considerable variations between the 2 insects and among different life stages. Confused flour beetle was more susceptible to SO2 fumigation than rice weevil. Complete control of adults and all life stages of confused flour beetle was achieved in 3-h fumigations with 0.5% and 2.0% SO2, respectively. For rice weevil, 3-h fumigation with 1.5% SO2 resulted in 96.5% adult mortality and the fumigation with 2.0% SO2 resulted in 99.27% mortality of adults and 87.5% mortality of immature stages. Three-hour fumigations with 1% SO2 resulted in <5% egg survival to adults. The study demonstrated high efficacy of SO2 fumigation against the insects and suggested that SO2 fumigation has good potential for postharvest pest control on stored products. [ABSTRACT FROM AUTHOR]

The essential oil and the aqueous and ethanolic extracts obtained from the aerial parts of Pelargonium graveolens cultivated in Morocco were studied for their antioxidant and insecticidal activity against rice weevils (Sitophylus oryzae). The total phenolic content of the extracts was determined by a spectrophotometric method and the phenolic compounds were extensively characterized by HPLC-PDA/ESI-MS. To evaluate antioxidant potential, three in vitro assays were used. In the DPPH test, the ethanolic extract was the most active, followed by the aqueous extract and the essential oil. In the reducing power assay, excellent activity was highlighted for both extracts, while in the Fe2+ chelating activity assay, weak activity was observed for both the essential oil and the ethanolic extract and no activity for the aqueous extract. Concerning insecticide activity, the toxicity of the essential oil and the extracts was tested against rice weevils; the lethal concentrations LC50 and LC99 were determined, as well as the lethal time required for the death of 50% (LT50) and 99% (LT99) of the weevils. The essential oil had the highest activity; 100% mortality of S. oryzae was observed around 5, 9, and 8 days for the essential oil and the aqueous and ethanolic extracts, respectively. [ABSTRACT FROM AUTHOR]

This work focuses on the profiling of semiochemicals (SCS) from Callosobruchus maculatus, Sitophilus oryzae and Tribolium castaneum by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC–MS) technique. Totally, 6, 9 and 8 volatile compounds (VCS) were detected from C. maculatus, S. oryzae and T. castaneum, respectively. As a result of pherobase analysis and preference bioassay, stearic acid (C. maculatus); nonanal, lauric acid and stearic acid (S. oryzae); stearic acid (T. castaneum) were identified as new SCS that could be useful for integrated pest management (IPM) practices. [ABSTRACT FROM AUTHOR]

Rice beetle Sitophilus oryzae L. is one of the pests that must be eradicated because it plays a role in reducing rice quality, especially in storage warehouses.Usually the warehouse staff eradicate the rice beetle Sitophilus oryzae with artificial insecticides. However, artificial insecticides are not very friendly to the environment. Researchers try to bring solutions to these problems. This research describes a solution to create natural insecticides derived from plants. It has been proven that natural insecticides are much more environmentally friendly than artificial insecticides. This research used the simplicia powder of the Butterfly Pea Clitoria ternatea L. and the Purple Lavender Lavandula officinalis L. as a test material to see its toxin ability against the rice beetle Sitophyllus oryzae to cause mortality. Researchers used quantities of 2 grams, 4 grams, 6 grams, and 8 grams which were supplemented with controls on each plant. The results of the data obtained are displayed in graphical form and using a Completely Randomized Design (CRD) and using a further test of Honest Significant Difference (BNJ) using the SPSS ver.25 application to find out the significant difference between the test materials. It can be concluded that the Purple Lavender simplicia powder Lavandula officinalis L.can kill the Rice Beetle Sitophyllus oryzae more, with the number of deaths reaching 63 tails and a quantity of 8 grams with the highest mortality rate. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticide seed treatments are commonly used in rice (Oryza sativa) production to control rice water weevil (Lisorhoptrus oryzophilus). With the use of neonicotinoid seed treatments, there is potential that honey bees (Apis mellifera) could be exposed to neonicotinoids through translocation to the pollen. Studies were conducted in 2015 and 2016 to determine the level of neonicotinoids present in flag leaves, pollen, and grain of rice. Thiamethoxam was applied as a seed treatment and foliar prior to flooding. Clothianidin was applied as a seed treatment and as a foliar at a preflood and postflood timing. Subsamples of flag leaves, pollen, and grain were analyzed for positive neonicotinoid detections and abundance. Thiamethoxam was detected in 8.9% of samples and clothianidin was detected in 1.4% of samples. For both thiamethoxam and clothianidin, more positive samples were observed in flag leaf samples than in pollen or grain. An average of 4.30 ng/g of thiamethoxam was detected in flag leaves from seed-applied thiamethoxam. An average of 1.25 ng/g of clothianidin was found in flag leaves from a preflood application of clothianidin. A survey of honey bees present in rice fields was conducted in Mississippi and Arkansas to determine the abundance of honey bees present in rice fields based on the time of day. Honey bee densities were low in rice, with less than 5% and 3% positive detections observed in Mississippi and Arkansas, respectively. More positive detections and higher densities of honey bees were observed for mid-day sampling than for morning or evening sampling. [ABSTRACT FROM AUTHOR]

The traditional manual sampling method for detecting stored grain insect pests is labor-intensive and time-consuming, often yielding non-representative samples. However, to achieve more accurate monitoring, it is necessary to understand the distribution patterns of different insect pests within grain silo and their correlation with monitoring and sampling data. This study aimed to assess the population density and distribution of Sitophilus oryzae (rice weevil) in bulk wheat grain to predict insect dynamics effectively. Utilizing a probe trap in a wheat silo, adult insects were tracked across different population densities. The traps recorded captured pests, alongside temperature and humidity data. The correlation analysis revealed that rice weevils were active throughout the silo but less prevalent at the bottom, with the highest distribution near the upper surface. Temperature and humidity significantly influenced their activity, particularly within the 22 °C to 32 °C range. Higher population densities correlated with increased relative humidity, impacting weevil activity. Trapping data aligned with overall population density changes in the silo. This study will provide an accurate assessment of the population density of adult rice weevils in grain silos based on temperature changes in the upper part of the grain silo. [ABSTRACT FROM AUTHOR]

Combination of crop protectants is an important approach to increase insecticidal efficacy and reduce the application rates. In this study, the insecticidal efficacy of spinosad and seven monoterpenes, alone and in binary combinations, was evaluated against Sitophilus oryzae (L.) (Coleoptera: Curculionidae) in stored wheat. Spinosad was tested at application rates of 0.1 and 0.5 mg/kg while monoterpenes were tested at 0.5, 1.0 and 2.0 g/kg. Mortality of adults after 7, 14 and 21 days, progeny reduction after 45 and 90 days, and grain weight loss were recorded for all treatments. The results showed that the complete mortality (100.0%) of S. oryzae adults was observed in wheat treated with 0.5 mg/kg of spinosad + 2.0 g/kg of carvone or P-cymene or menthone after 21 days. At the same time, no progeny of S. oryzae was resulted in the combined treatments (0.5 mg/kg of spinosad + 2.0 g/kg of carvone or 0.5 mg/kg of spinosad + 2.0 g/kg of P-cymene) after 45 and 90 days. The same trends were observed for grains weight loss as the binary treatments at highest application rates preserved the wheat seeds free from damage caused by S. oryzae for 90 days. [ABSTRACT FROM AUTHOR]

This study investigates the bioactivities of the leaf extract of Acalypha godseffiana (Muell Arg.) and the stem bark extract of Alstonia boonei (De Wild) against Sitophilus oryzae (Linnaeus) and Sitophilus zeamais (Motschulsky) at different concentrations (2.5, 5.0, 7.5, 10.0, and 12.5% %). The relative growth rate (RGR), relative consumption rate (RCR), and efficiency of conversion of ingested food (ECI) of both Sitophilus species were assessed using extract-treated wheat flour discs. The contact toxicity and effects of both extracts on the adult emergence of both weevils were also determined. Control experiments were set up for all the bioassays. Phytochemical compounds (tannins, saponins, anthraquinones, cardiac glycosides, flavonoids, and alkaloids) in each botanical extract were checked. Except for anthraquinones, which was lacking in A. boonei but marginally present in A. godseffiana, both extracts contain all the tested phytochemicals in either low, moderate, or high amounts. The LC50 values showed that both extracts had higher toxicity to S. zeamais at 24 and 48 h and to S. oryzae at 72 and 96 h. Both extracts at 12.5% significantly decreased adult emergence and evoked higher inhibition in adult emergence of both Sitophilus species relative to controls. RGR, RCR, and ECI generally decreased as extract concentrations increased. At 12.5%, A. boonei and A. godseffiana considerably decreased the RCR of S. oryzae and S. zeamais, respectively. Additionally, the ECI of both species was significantly lower relative to controls. Conclusively, the two extracts evoked insecticidal, anti-nutritional, and significantly reduced adult emergence of both Sitophilus species relative to controls. [ABSTRACT FROM AUTHOR]

Simple Summary: Many species of insects that infest stored products have developed a resistance to phosphine as a result of its widespread use to control stored-product pests. There is a significant opportunity for the development of natural fumigants as eco-friendly methods for controlling pests in stored products. A plant-derived molecule called methyl benzoate (MBe) is an example of a volatile organic compound that has potent insecticidal and fumigation toxicity. In this research, we examined its potential efficacy as a fumigation agent against phosphine-resistant strains of the lesser grain borer and rice weevil. Phosphine (PH3) has been widely used as a fumigant in food storage, but increasing PH3 resistance in major pests makes finding alternative fumigants urgent. Methyl benzoate (MBe), a volatile organic compound regarded to be a food-safe natural product, has recently demonstrated significant toxicity against a variety of insect pests. This study is the first evaluation of the fumigation toxicity of three benzoate compounds, MBe, vinyl benzoate, and ethyl benzoate, against PH3-susceptible and PH3-resistant strains of Rhyzopertha dominica and Sitophilus oryzae. All strains were exposed to the compounds at concentrations up to 20 µL/1.5 L air for 24 h. Compared to vinyl benzoate and ethyl benzoate, MBe induced higher mortality rates in all strains at all concentrations. When food was made available, the lethal median concentration for MBe was 10–17-fold higher than when tested without food. Moreover, no significant differences were observed between the responses of the PH3-susceptible and PH3-resistant strains to the compounds. Notably, S. oryzae was more susceptible to MBe. In laboratory settings, MBe successfully controlled PH3-resistant strains of R. dominica and S. oryzae, making it a viable option for PH3-resistance management. Thus, MBe might be suitable for food security programs as an environmentally benign alternative fumigant. [ABSTRACT FROM AUTHOR]

Maize is a major staple food in Africa, its production and post-harvest generally occurs on smallholder farmers' properties, where significant food losses occur in the field during harvesting, processing and storage. Most smallholder farmers lack access to modern methods of harvesting, processing and storage. Generally, the storage structures used are ineffective against storage pests, leading to postharvest losses due to insect pests that, in some cases, can reach about 40% of the total production. Pest control is generally scarce, and when adopted, it is based on local knowledge-based pest control alternatives or on the application of synthetic pesticides known to be harmful to the environment and human and animal health. So, alternative pest control methods commonly found include the use of inert dust as an integrated pest management approach, without residual effects and ideal for food safety. This study aimed to determine the efficacy of charcoal powder (CP) and rock dust (RD) alone or combined with diatomaceous earth (DE) in the control of rice weevil (Sitophilus oryzae). Maize grains were treated and infested by the addition of Sitophilus oryzae, on the day they were treated and, 30 and 60 days after treatment. Mortality was assessed at 10 and 20 days after each infestation. Emerged insects were counted 40 days after the second mortality assessment for each infestation period. At 90 days after treatment, the seed germination test was performed. The best treatments for Sitophilus oryzae control (mortality) and F1 emergence reduction were RD (0.5, 0.25 and 0.10 g/kg), RD+DE (0.5+0.05, 0.25+0.05 and 0.10+0.05 g/kg), and CP+DE (1.0+0.05, 0.50+0.05 and 0.25+0.05 g/kg). The RD and RD+DE remained efficient in maize treated and stored for 60 days. The treatments did not interfere with seed germination. Rock Dusts, RD+DE, and CP have the potential to be used as stored grain protectants, providing economically and environmentally friendly pest control alternatives, especially in small-scale agriculture. In developing countries, especially in sub-Saharan Africa, studies for optimization and introduction of inert dusts tested in this research, have the potential to reduce post-harvest losses, improving food security. [ABSTRACT FROM AUTHOR]

Based on popularity and specialty, seven traditional rice varieties were tested for resistance reactions in terms of physicochemical properties against rice weevil, Sitophilus oryzae and compared with the improved high yielding rice varieties during 2019-2021. The result revealed that the aromatic rice variety Kon joha was the least suffered (11.67%) under the husked condition, whereas the aromatic traditional rice variety Bokul joha was the least suffered (53.00%) under the dehusked conditions at 18 days after infestation. Amongst the traditional varieties, the Black rice variety suffered maximum weight loss of 60.16% under de-husked conditions. All tested physical and biochemical parameters revealed a significant positive correlation with weight loss (r=0.87), total soluble protein (r=0.86), 1000 grain weight (r=0.74), moisture content (r=0.54), germination loss (r=0.89) and seed vigor loss (r=0.54) at 180 days of infestation under husked condition, while significant positive correlation with weight loss (r=0.91), starch content (r=0.98), crude protein content (r=0.94), L/B ratio (r=0.88), 1000 grain weight (r=0.50) and moisture content (r=0.87) at 180 days of infestation under de-husked condition. The rice grains possessing a high percentage of starch and protein, but a low per cent of crude fat was found more prone to infestation by S. oryzae. [ABSTRACT FROM AUTHOR]

There is a high interest in utilizing natural bioactive products derived from plants as a substitute for synthetic chemicals in the industry. This research focuses on the phytochemical composition of essential oils (EOs) of Ammi visnaga L. and Trachyspermum ammi L and their insecticidal activity against Sitophilus oryzae (L.), a common pest found in stored cereals. The EOs were extracted through steam distillation and analyzed using gas chromatography coupled with mass spectrometry (GC-MS). The EOs of A. visnaga consisted of twenty-four components, with Abietadiene (41.23%) being the most abundant, followed by linalool (25.54%) and limonene (19.04%). On the other hand, the EOs of T. ammi consisted of twenty-eight main components, with isothymol being the most abundant (51.88%). The results revealed that the EOs of T. Ammi (DL50 = 0.1 µL EOs/L of air) were more toxic than A. visnaga (0.38 µL EOs/L of air), with the toxicity varying based on doses and exposure periods. To further understand the molecular mechanisms underlying this activity, molecular docking and dynamic simulations were performed using the major chemical constituents of the oils. The simulation results indicated that the major compounds, Abietadiene and isothymol, interact with the catalytic sites of the target proteins, inhibiting acetylcholinesterase and chitin synthase. These interactions form energetically favorable systems that remain stable throughout the molecular dynamic period. This research provides valuable insights into the potential of these EOs as natural insecticides and highlights the importance of molecular modeling in understanding the biological activities of plant-derived compounds. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Protection & Pathology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the ability of internal‐ and external‐infesting stored product insects to vector microbes is important for estimating the relative risk that insects pose to postharvest commodities as they move between habitat patches and in the landscape. Thus, the aim of the current study was to evaluate and compare the microbial growth in novel food patches at different dispersal periods by different populations of Sitophilus oryzae (e.g., internal‐infesting) and Lasioderma serricorne (e.g., external‐infesting). Adults of both species collected from laboratory colonies or field‐captured populations were either placed immediately in a novel food patch, or given a dispersal period of 24 or 72 h in a sterilized environment before entering a surrogate food patch. Vectored microbes in new food patches were imaged after 3 or 5 days of foraging, and microbial growth was processed using ImageJ while fungal species were identified through sequencing the ITS4/5 ribosomal subunit. We found that increasing dispersal time resulted in multiple‐fold reductions in microbial growth surrogate food patches by L. serricorne but not S. oryzae. This was likely attributable to higher mobility by S. oryzae than L. serricorne. A total of 20 morphospecies were identified from 13 genera among the 59 sequences, with a total of 23% and 16% classified as Aspergillus and Penicillium spp. Our data suggest that there is a persistent risk of microbial contamination by both species, which has important food safety implications at food facilities. The study investigated how Sitophilus oryzae and Lasioderma serricorne, two types of stored product insects (internal‐ and external‐infesting), affect microbial growth in new food patches over varying dispersal periods. We found that longer dispersal times led to a significant reduction in microbial growth in food patches for L. serricorne but not for S. oryzae, likely due to differences in mobility between the two species. This suggests an ongoing risk of microbial contamination from both insect types, with implications for food safety in storage facilities. [ABSTRACT FROM AUTHOR]

The bioefficacy of several inert materials, such as Diatomaceous earth (DE), bentonite, and biochar enhanced with pirimiphos-methyl against Sitophilus oryzae, was used to evaluate the insecticidal activity of three new formulations using the technique of mixing with grain. DE was the most effective material (LC50 3.198 g/kg), followed by biochar LC50 3.709 g/kg, whereas bentonite was the least effective (LC50 3. 979 g/kg). The three materials were loaded with pirimiphos-methyl (0.5%). The formula of Pirimiphos-methyl with DE reported the highest significant effect compared to the other two formulations, with an LC50 value of 0.082 g/kg. DE formula had a co-toxicity coefficient value that was 6.46 times greater than pirimiphos-methyl, followed by the biochar formula, which was 1.74 times more effective, and the bentonite formula, which had a 0.69-fold increase in activity. In the laboratory examination of the wheat's free and compact bulk densities after being treated with LC50s of each dust material, DE slightly affected wheat-free bulk density. Still, both bentonite and biochar reduced the free bulk density. However, all the tested materials decreased in compact bulk density. The germination percentages of wheat treated with LC50 values of DE and bentonite and biochar after 10 days of storage revealed no significant difference between treated and untreated seeds after 7 days of germination. [ABSTRACT FROM AUTHOR]

Sitophilus oryzae and Sitophilus zeamais are among the main pests of stored grains worldwide, they are very similar species and have great destructive potential, causing numerous damages to grain production. The control of these insects occurs, in general, through chemical insecticides such as the agrochemicals pirimiphos-methyl, an organophosphate, and bifenthrin, a pyrethroid, which are widely used to prevent infestation. Four strains of these two species were exposed to the two classes of agrochemicals mentioned. The polyacrylamide gel electrophoresis technique was used to identify the esterase patterns of the species and eight esterases were identified for S. zeamais, of which four cholinesterases, two carboxylesterases, one acetylesterase, and one arylesterase; and seven esterases for S. oryzae, being four cholinesterases, two carboxylesterases, and one acetylesterase. After exposure to agrochemicals, through dose-response bioassays, the LC50 was determined for each strain, with the SoB strain of S. oryzae being the most resistant to bifenthrin, the SzB strain of S. zeamais being the most resistant to pirimiphos-methyl and the SoA strain of S. oryzae was the most sensitive to both compounds. Analysis of the esterase patterns of insects exposed to these agrochemicals revealed the inhibition and probable involvement of carboxylesterases and cholinesterases in the detoxification processes of organophosphates and pyrethroids. [ABSTRACT FROM AUTHOR]

In this study, bacteria residing in the gut of the rice weevils (Sitophilus oryzae L.) (Coleoptera: Curculionidae) feeding on aflatoxin-contaminated corn kernels were isolated and evaluated for their ability to suppress Aspergillus flavus and to remove/degrade aflatoxin B1 (AFB1). Four morphologically distinct S. oryzae gut-associated bacterial isolates were isolated and identified as Bacillus subtilis (RWGB1), Bacillus oceanisediminis (RWGB2), Bacillus firmus (RWGB3), and Pseudomonas aeruginosa (RWGB4) based on 16S rRNA gene sequence analysis. These bacterial isolates inhibited A. flavus growth in the dual culture assay and induced morphological deformities in the fungal hyphae, as confirmed by scanning electron microscopy. All four bacterial isolates were capable of removing AFB1 from the nutrient broth medium. In addition, culture supernatants of these bacterial isolates degraded AFB1, and the degradation of toxin molecules was confirmed by liquid chromatography-mass spectrometry. The bacterial isolates, B. subtilis RWGB1, B. oceanisediminis RWGB2, and P. aeruginosa RWGB4, were capable of producing antifungal volatile organic compounds that inhibited A. flavus growth. These results suggest that the bacterial isolates from S. oryzae gut have the potential to bind and/or degrade AFB1. Further research on their application in the food and feed industries could enhance the safety of food and feed production. [ABSTRACT FROM AUTHOR]

Rice grains are often infested by Sitophilus oryzae and Corcyra cephalonica, causing quality and quantity losses. In this study, the insecticidal effects of inert dust (diatomaceous earth (DE), calcium carbonate, kaolin (KA), rock phosphate and silica gel) on S. oryzae adults and C. cephalonica larvae were assayed. Four concentrations of each inert dust were tested at 2,3,4 and 5% on rice grains. Results indicated that diatomaceous earth and phosphate rock 5% lead to the highest insecticidal action with adult mortality of 98.3 and 96.6% for S. oryzae adults, 15 days post-treatment, respectively. As well, diatomaceous earth and phosphate rock 5% lead to the highest insecticidal action with larval mortality of 100.0% for C. cephalonica larvae after 7 days. On the contrary, treatment with 5% silica gel recorded the lowest toxicity to S. oryzae adults (65.66%) after 15 days of exposure. While calcium carbonate 5% resulted from the lowest toxicity C. cephalonica larvae (61.2%) after 7-day exposure. According to the obtained results, the highest reduction in the progeny of S. oryzae adults was registered in treatments with diatomaceous earth (5%) and kaolin (5%), being 91.4 and 91.3%, respectively. As for the highest reductions in the progeny of C. cephalonica larvae, in treatments with diatomaceous earth (5%) and phosphate rock (5%), those were 97.4and 97.2%, respectively. All treatments with inert dust caused a reduction of weight loss and damage of rice grains 60 days post-treatment in comparison with untreated grains. Results showed that all the tested inert dusts treatments except silica gel increased germination percentages of seeds than the control. The obtained results indicated that inert dusts may be considered, safe and available in the local environment, so, they are used as alternatives to insecticides for the control of S. oryzae and C. cephalonica infestations to stored rice grains. [ABSTRACT FROM AUTHOR]

Phosphine is the most common fumigant used for stored product protection, and its use intensified with the global phasing out of methyl bromide due to its ozone depletion characteristics. These use patterns led to phosphine resistance, which was subjected to a globe-wide survey in the 1970's, but without a subsequent (global) update. Thus, the present work aimed to undertake a comprehensive review of the phosphine resistance literature published since the initial survey in 1975 until 2021. Next, meta-analyses were used to synthesize and quantify the resistance observed within the main insect pest species of stored products. Forty-six papers were recognized surveying 13 species of stored product insect species, encompassing 980 populations around the world; 72.96% of these populations exhibited phosphine resistance, and 10 out of the 13 species evaluated exhibited resistance in more than 60% of the populations tested. The most widespread problems were observed with the lesser grain borer (Rhyzopertha dominica), the rice weevil (Sitophilus oryzae), and the red flour beetle (Tribolium castaneum). The frequency of resistant individuals ranged from 12 to 48% for the populations. The levels of phosphine resistance were higher for the lesser grain borer (73-fold on average), followed by the red flour beetle (32-fold), and the maize weevil (28-fold). Furthermore, a considerable variability was observed within species and among localities. Therefore, phosphine resistance remains an ongoing problem and worldwide concern, with increasing levels and prevalence among key pest species of stored products, although reports and monitoring are largely circumscribed to four countries–Australia, Brazil, Greece, and the US. [ABSTRACT FROM AUTHOR]

The rice weevil (Sitophilus oryzae L.) and the cigarette beetle (Lasioderma serricorne F.) are primary and secondary insect pests that cause significant damage to stored grains and commodities. The goal of this study was to evaluate the physicochemical properties and insecticidal activity of Origanum vulgare (L.) (OV) and Laurus nobilis (L.) (LN) essential oils (EOs) in polymeric nanoparticles (PNs) prepared using the melt dispersion technique with polyethylene glycol (PEG 6000) as the matricidal material. In PNs, the monocyclic monoterpenes were retained in high proportions after encapsulation. Physicochemical analyses revealed that OV and LN PNs had mean sizes of 295 and 429 nm, respectively, with a loading efficiency of almost 90%, and a polydispersity index ≤ 0.25 (monodisperse samples). Against Sitophilus oryzae, only OV PN significantly enhanced the lethal effect of EO, whereas on L. serricorne, both PNs. It was demonstrated that, on both pests, OV EO and its PNs increased their sensitivity to pyrethroids, whereas LN oil and their PNs promote this effect only on S. oryzae. The PNs of OV and LN altered the nutritional physiology and behavior variables of both stored product pest and prolonged the repellent effect of the EOs on S. oryzae and L. serricorne up to 60 and 48 h. Ecotoxicity bioassays demonstrated that OV and LN EOs and their PNs were harmless to terrestrial non-target organisms and had slight negative effects on aquatic non-target organisms. Finally, PNs did not affect viability of primary osteoblast cells. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Journal of Agricultural Sciences (SJAS) is the property of Beni Suef University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The preservation of post-harvest storage products, such as grains and rice, is often plagued by insect pests, with the rice weevil (Sitophilus oryzae L.) standing out as important. This study evaluates the efficacy of spice extracts of Syzygium aromaticum, Trigonella foenum-graecum and Ferula assa-foetida against S. oryzae at varying concentrations. Extracts exhibited toxicity that inhibited egg development and larval progression, with deformations observed at lower concentrations leading to larval death at higher concentrations. Qualitative and quantitative assessment of insect α-amylase activity revealed significant decreased activity with prolonged exposure. The study demonstrated increasing mortality rates with the combined spice extracts displaying the highest efficacy followed by S. aromaticum, T. foenum-graecum, and F. assa-foetida extracts, indicating promising insecticidal activity against S. oryzae. [ABSTRACT FROM AUTHOR]

Plant volatilomics such as essential oils (EOs) and volatile phytochemicals (PCs) are known as potential natural sources for the development of biofumigants as an alternative to conventional fumigant pesticides. This present work was aimed to evaluate the fumigant toxic effect of five selected EOs (cinnamon, garlic, lemon, orange, and peppermint) and PCs (citronellol, limonene, linalool, piperitone, and terpineol) against the Callosobruchus maculatus, Sitophilus oryzae, and Tribolium castaneum adults. Furthermore, for the estimation of the relationship between molecular descriptors and fumigant toxicity of plant volatiles, quantitative structural activity relationship (QSAR) models were developed using principal component analysis and multiple linear regression. Amongst the tested EOs, garlic EO was found to be the most toxic fumigant. The PCs toxicity analysis revealed that terpineol, limonene, linalool, and piperitone as potential fumigants to C. maculatus (< 20 µL/L air of LC50), limonene and piperitone as potential fumigants to T. castaneum (14.35 and 154.11 µL/L air of LC50, respectively), and linalool and piperitone as potential fumigants to S. oryzae (192.27 and 69.10 µL/L air of LC50, respectively). QSAR analysis demonstrated the role of various molecular descriptors of EOs and PCs on the fumigant toxicity in insect pest species. In specific, dipole and Randic index influence the toxicity in C. maculatus, molecular weight and maximal projection area influence the toxicity in S. oryzae, and boiling point and Dreiding energy influence the toxicity in T. castaneum. The present findings may provide insight of a new strategy to select effective EOs and/or PCs against stored product insect pests. [ABSTRACT FROM AUTHOR]

Interactions between animals and microbes are ubiquitous in nature and strongly impact animal physiology. These interactions are shaped by the host immune system, which responds to infections and contributes to tailor the associations with beneficial microorganisms. In many insects, beneficial symbiotic associations not only include gut commensals, but also intracellular bacteria, or endosymbionts. Endosymbionts are housed within specialized host cells, the bacteriocytes, and are transmitted vertically across host generations. Host–endosymbiont co-evolution shapes the endosymbiont genome and host immune system, which not only fights against microbial intruders, but also ensures the preservation of endosymbionts and the control of their load and location. The cereal weevil Sitophilus spp. is a remarkable model in which to study the evolutionary adaptation of the immune system to endosymbiosis owing to its binary association with a unique, relatively recently acquired nutritional endosymbiont, Sodalis pierantonius. This Gram-negative bacterium has not experienced the genome size shrinkage observed in long-term endosymbioses and has retained immunogenicity. We focus here on the sixteen antimicrobial peptides (AMPs) identified in the Sitophilus oryzae genome and their expression patterns in different tissues, along host development or upon immune challenges, to address their potential functions in the defensive response and endosymbiosis homeostasis along the insect life cycle. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'. [ABSTRACT FROM AUTHOR]

Simple Summary: Natural insecticides are currently given high priority in Integrated Pest Management (IPM) protocols. To this end, diatomaceous earth (DE) has gained a lot of attention as an environmentally friendly alternative to conventional insecticides that can successfully repel and control a diverse variety of the most important stored-product insect pests, such as the species Sitophilus, Rhyzopertha, Tribolium, and others. However, most published research about the DEs' insecticidal efficacy has been conducted in simplistic short-term laboratory experiments, excluding the evaluation of the persistence of such ingredients in grain applications. In this study, we evaluated two different DE formulations derived from a single deposit from Greece, when applied in wheat and maize against two primary stored-product insect pests, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). Based on the results, the DE application was effective and persistent as a grain protectant against major stored-product insects for a storage period of six months. This study provides more evidence for the successful utilization of these natural insecticides for long-term protection of stored products from insect infestations, as an alternative to residual insecticides and fumigants that are commonly used in stored-grain protection systems or as part of integrated pest management (IPM) strategies. 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. [ABSTRACT FROM AUTHOR]

Simple Summary: The two closely related maize and rice weevils exhibit differential host preferences among stored maize, wheat, and paddy grains. The maize weevil adults prefer to select maize, followed by paddy and wheat, while rice weevil adults mainly migrate towards wheat. The 2-ethylhexanol, piperitone, and (+)-Δ-cadiene are the major components in volatiles from both maize and wheat, but the abundance of these chemicals is much lower in maize than in wheat. The volatile limonene was only detected in paddy. The 2-ethylhexanol, piperitone, and (+)-Δ-cadiene were all attractive to both weevils, whereas limonene was attractive only to rice weevils. The different volatile profiles among the grains and the sensitivity of the two pest species towards these volatiles may explain the behavioral differences between maize and rice weevils in selecting host grains. The variance in sensitivity of maize and rice weevils towards host volatile chemicals with abundance differences is likely a determinant driving the two insect species to migrate towards different host grains. The Sitophilus zeamais (maize weevil) and Sitophilus oryzae (rice weevil) are two insect pests that have caused huge economic losses to stored grains worldwide. It is urgent to develop an environmentally friendly strategy for the control of these destructive pests. Here, the olfactory-mediated selection preference of the two weevil species to three stored grains was analyzed, which should help establish a pull–push system in managing them. Bioassays showed that maize weevil adults prefer to select maize, followed by paddy and wheat, while rice weevil adults mainly migrate towards wheat. Volatile analyses revealed that 2-ethylhexanol, piperitone, and (+)-Δ-cadiene are the major components in volatiles from both maize and wheat, but the abundance of these chemicals is much lower in maize than that in wheat. The volatile limonene was only detected in paddy. Y-tube bioassays suggest that 2-ethylhexanol, piperitone, and (+)-Δ-cadiene were all attractive to both weevils, whereas limonene was attractive only to rice weevils. Overall, maize weevil appeared more sensitive to the tested volatiles based on having much lower effective concentrations of these volatiles needed to attract them. The differences in volatile profiles among the grains and the sensitivity of the two species towards these volatiles may explain the behavioral differences between maize and rice weevils in selecting host grains. The differences in sensitivity of maize and rice weevils towards host volatile components with abundance differences are likely determinants driving the two insect species to migrate towards different host grains. [ABSTRACT FROM AUTHOR]

Despite being successful in preventing pests from entering stored goods, residual synthetic pesticides have had a negative impact on the environment. However, the prohibitive cost of synthetic pesticides and the risk of target pests developing insecticide resistance have prompted researchers to develop alternative management strategies. Since plant-based pesticides are biodegradable and less dangerous for organisms other than the target species, they are a useful alternative to chemical pesticides. The aim of the present study was to investigate the effectiveness of plant extract in preventing the rice weevil Sitophilus oryzae (Linnaeous) (Coloptera: Curcolinidae) from infesting stored-products. For toxicity and synergism against S. oryzae, aqueous extracts of Cannabis sative L., Dodonaea visicosa L., and Parthenium hysterophorus L., were evaluated at different concentrations. D. viscosa and P. hysterophorus extract concentrations were 0.25, 0.5, 1.0, 2.0, and 3.0%, and C. sativa extract concentrations were 0.62, 1.25, 2.5, 5.0, and 7.5%. A completely random design with three replications was used, with distilled water serving as the control. The experimental setting was kept at 27± 2oC and 65±5% R.H. The findings showed that D. visicosa, P. hysterophorus, and C. sativa caused 97%, 90%, and 83% of mortalities at the highest doses, respectively. At highest concentrations, the mortalities found for binary combinations of D. viscosa and P. hysterophorus, D. viscosa and C. sativa, and P. hysterophorus and C. sativa, respectively, were 80%, 77%, and 70%. When used in combination, the effects of D. visicosa, P. hysterophorus, and C. sative produce 100% mortalities, indicating synergism. In single applications for all treatments, plant extracts were the most toxic. However, when used in combination, S. oryzae is completely killed. Phytochemical screening test all the compounds were detected but saponins and coumarins were higher in D. visicosa and P. hysterophorus. As a result, mixing plant extract greatly increases the effectiveness of reducing S. oryzae in storage facilities. Smallscale farmers may benefit from the study's findings since they may offer them a grain storage approach that is both practical and affordable. [ABSTRACT FROM AUTHOR]

Insufficient storage practices and frequent infestations of insect pests pose significant obstacles to sesame production and storage, adversely affecting the quality and quantity of seeds. This forces farmers and traders to sell their crops at lower prices immediately after threshing to avoid market rejection caused by pests and mold damage during storage. The objective of this study was to investigate the insect species dynamics and the losses of on-farm-stored sesame seeds during the 2017- 2018 production year. Sesame seed samples obtained from randomly selected 431farm households in five districts were analyzed to determine the insect species present, insect density, seed weight loss, seed damage, germination percentage, and dockage using R software version 4.2.2. Biophysical parameters such as inter-granular temperature, seed moisture, and relative humidity were also recorded. Furthermore, interviews were conducted with the 431 farm households to gather information on their seed storage methods, practices for controlling insect pests, and the varieties of sesame they produce and store. The findings revealed the presence of 13 arthropod species from four orders (Coleoptera, Hemiptera, Hymenoptera, and Lepidoptera) which belongs to eight families (Tenebrionidae, Silvanidae, Bostrichidae, Curculionidae, Carabidae, Coreidae, Formicidae, and Pyralidae) in the stored sesame seeds at the study site. The most prevalent species was the flour beetle (Tribolium spp.), accounting for 44.26% of the infestation, followed by the rice moth, lesser grain borer, and rice weevil, which constituted 28.2%, 15.72%, and 4.88% of the infestation, respectively. The farmers grew and stored nine different cultivars along with one improved sesame variety called setit-1. On average, there was a 1.97% loss in seed weight, with insect pests causing damage to 8.3% of the seeds. The study districts exhibited an average of 3.79 insects per kilogram of sesame seeds, and the seeds showed a mean germination rate of 77%, which was significantly influenced by the extent of insect damage. The study underscores the significant challenges faced by sesame production and storage in Ethiopia due to inadequate storage practices and infestation by insect pests, resulting in diminished seed quality and quantity. To mitigate the losses incurred from storing sesame on farms, effective measures should be implemented, including improved storage practices and efficient pest control methods. [ABSTRACT FROM AUTHOR]

Due to global warming, the rice weevil is an increasing threat. Various species of weevils coexist with endosymbiotic Sodalis pierantonius. This study aimed to check whether different chemical properties of different cultivars of common wheat and barley grain cause disturbances in insect feeding and rearrangements of the rice weevil microbiome. It has been observed that foraging increases in the case of cultivars with low protein content, high steric acid content, and low antioxidant activity. Cultivars with higher antioxidant activity, a tendency was observed to increase the number of adult insects and the intensity of feeding. However, the correlation of number of offspring generations and antioxidants was different depending on species of cereals (R2=0.9 for barley, R2<0.1 for wheat). Changes of dominance classes of selected Enterobacteriaceae partially shifted the microbiomes of insects feeding on different barley varieties. In contrast, in some wheat cultivars, displacement of the dominant genus Sodalis by genera Staphylococcus or Mammaliicoccus was observed, severely reducing the rice weevil's foraging ability. Nevertheless, Sodalis sp. almost always dominated (from 16.7 to 90.07% for wheat and from 63.4 to 90.9% for barley), and no correlation was observed between species and variety factors of cereals and their abundance. [ABSTRACT FROM AUTHOR]

Background: A number of storage pests viz., Rhyzopertha dominica (F.), rice weevil, Sitophilus oryzae (L.), granary weevil, Sitophilus granarius (L.) and Khapra beetle, Trogoderma granarium (Evert.) damage stored wheat. However, S. oryzae is considered a primary pest of stored wheat and has been reported to prefer soft textured wheat cultivars. Methods: The grains of three bread (soft textured) viz., HD2967, PDW314, PBW658 and three durum wheat (hard textured) cultivars viz., WHD943, PBW621, PDW291 were screened for feeding response by rice weevil, Sitophilus oryzae L. in the laboratory. Each cultivar seed was properly cleaned and disinfested before its use. A 100 g seed sample of each cultivar was taken into the plastic jars. Of the pure culture, ten 1-2 week young one insects (1:1 sex ratio) were released into the jars each containing different cultivar grains. The jars were covered with white muslin as three separate storage sets, i.e., 30, 60 and 90 days after storage to record data observations. Result: Durum wheat cultivars being low in protein contents were comparatively less preferred for pest feeding and cultivar PDW291 was found highly resistant based on low insect emergence, grain damage and weight loss. The bread wheat cultivars due to high protein contents were highly preferred by the pest and cultivar HD2967 showed maximum preference. The biochemical properties like ash contents and crude fibres showed positive while crude fats and protein a negative correlation with the pest infestation. [ABSTRACT FROM AUTHOR]

Cyclohexanone is a major precursor for nylon production and is also used as a pesticide solvent. In this study, cyclohexanone was evaluated as a fumigant against rice weevil adults, confused flour beetle adults, western flower thrips larvae and adults, spotted wing drosophila adults, and subterranean termite workers. Cyclohexanone fumigation was effective against all 5 insects, and there were considerable variations in susceptibility to cyclohexanone fumigation among the 5 species. At 20 °C, complete control of spotted wing drosophila adults was achieved in 1-h fumigation with 25 μl/l of cyclohexanone and complete control of eastern subterranean termite workers was achieved in 3-h fumigations with 50 μl/l dose of cyclohexanone. Stored-product insects confused flour beetle, and rice weevil adults were more tolerant to cyclohexanone fumigation. Fumigations of 24 h with 75 μl/l dose of cyclohexanone caused 100% mortality of rice weevil adults and 98% mortality of confused flower beetle adults. Even at a 100 μl/l dose, the 24-h fumigations did not achieve 100% mortality of confused flour beetle adults. At 5 °C, complete control of western flower thrips was achieved in 3- and 6-h fumigations with 100 and 50 μl/l doses of cyclohexanone, respectively. Cyclohexanone vapor concentrations were measured using cyclohexanone detector tubes. Vapor concentrations were far below the expected saturation concentration indicating that most cyclohexanone did not exist as vapor in fumigation chambers. The results of effective control of all 5 insect species suggest that cyclohexanone has the potential to be used as a fumigant for postharvest pest control. [ABSTRACT FROM AUTHOR]

This correction notice addresses errors in a publication about the repellent effects of fungal volatile organic compounds (VOCs) on the banana black weevil. The correction includes a mistake in the legend for Figure 4 and clarifies that the olfactometric tests were conducted with a different compound due to availability. The corrected abstract highlights the potential use of these VOCs for managing the weevil in the field. The conclusion suggests further research to evaluate the effectiveness of new VOCs as weevil repellents. The article discusses the benefits of integrated pest management for banana crops and its potential impact on global food production. The scientific conclusions of the study remain unchanged. [Extracted from the article]

The management of stored-grain insects, including the rice weevil Sitophilus oryzae, is a challenge to ensure sound healthy grains. Botanical insecticides are safe and effective alternatives to chemical insecticides and are recommended to be used in the Integrated Pest Management program. Also, the manipulation of storage temperature is a promising tool in the management of stored-product insects. Laboratory experiments on the effects of 9 different plant powders at 5% concentration and two temperatures 20 and 25 °C, on the biology and damage potential of rice weevil are conducted. Neem Seed Kernel Powder (NSKP) was the most effective treatment recording fecundity of 3.87 and 7.42 eggs, egg to the adult stage of 41.2 and 34.9 days, adult emergence rate of 3.58 and 5.95%, male longevity of 3.0 and 2.4 days, female longevity of 3.3 and 2.8 days, mortality rate of 92.14 and 96.51%, seed weight loss of 0.62 and 1.10% and seed damage of 5.92 and 7.53% at 20 and 25 °C, respectively. Chili dried fruit and Calotropis leaf powders exhibited good results. Lantana leaf powder was the least effective at both temperatures and for all the above parameters. The use of NSKP, chili dried fruit and Calotropis leaves powders at a low temperature of 20 °C is an effective measure for controlling rice weevil while preserving the vitality and activity of the seeds as much as possible. [ABSTRACT FROM AUTHOR]

Abstract Understanding the ability of internal‐ and external‐infesting stored product insects to vector microbes is important for estimating the relative risk that insects pose to postharvest commodities as they move between habitat patches and in the landscape. Thus, the aim of the current study was to evaluate and compare the microbial growth in novel food patches at different dispersal periods by different populations of Sitophilus oryzae (e.g., internal‐infesting) and Lasioderma serricorne (e.g., external‐infesting). Adults of both species collected from laboratory colonies or field‐captured populations were either placed immediately in a novel food patch, or given a dispersal period of 24 or 72 h in a sterilized environment before entering a surrogate food patch. Vectored microbes in new food patches were imaged after 3 or 5 days of foraging, and microbial growth was processed using ImageJ while fungal species were identified through sequencing the ITS4/5 ribosomal subunit. We found that increasing dispersal time resulted in multiple‐fold reductions in microbial growth surrogate food patches by L. serricorne but not S. oryzae. This was likely attributable to higher mobility by S. oryzae than L. serricorne. A total of 20 morphospecies were identified from 13 genera among the 59 sequences, with a total of 23% and 16% classified as Aspergillus and Penicillium spp. Our data suggest that there is a persistent risk of microbial contamination by both species, which has important food safety implications at food facilities.

A reduction in rice quality may result from pest infestations in storage facilities. In addition to being a major pest of rice, the rice weevil (Sitophilus oryzae L.) is a problem in warehouses. Attacks by rice weevils may result in lower-quality rice. Using white pepper powder as a pesticide is one way to solve this issue. The purpose of this study is to ascertain how white pepper powder, a botanical pesticide, affects rice weevil pest mortality, as well as the optimal dosage and mode of administration. In this study, there were six treatments and four replications in a single factor totally randomized design. The rate at which rice weevil bugs died and the percentage of rice weight loss were the study's parameters. The results showed that the death of rice weevil pests was influenced using white pepper powder. The highest mortality rate was L5 at 52.5%, which is the best dose.

Sitophilus oryzae or commonly known as Rice Weevil is a pest that infests stored rice grains. The feeding and movement of this pest within the grain produce sounds that are audible to a high-performance microphone sensor. This study presents a method for early detection of Rice Weevils based on the frequency of the sound they produce. Sound features were extracted using MFCC and utilized as input features to train a Convolutional Neural Network (CNN). The classifier was evaluated using 2800 acoustic samples containing positive and negative datasets. The experimental results show that the method can be an alternative approach for the early detection of the presence of rice weevils in stored rice grains. [ABSTRACT FROM AUTHOR]

Chickpea (Cicer arietinum L.) is the most important winter season food legume in Ethiopia. Despite being a major producer and consumer of chickpeas, Ethiopia experiences lower yields due to biotic and abiotic stresses, particularly insect pest infestations during storage. This study aimed to evaluate the impact of different storage technologies and durations on the losses of stored chickpea seeds in terms of both quantity and quality. The experiment involved five storage technologies and three durations, spanning a period of 6 months, with data collected at 2‐month intervals. The results showed that the Purdue Improved Crop Storage (PICS) and Super GrainPro (SGP) bags effectively maintained intergranular temperature, seed moisture content, and relative humidity throughout the storage period, followed by the modified hermetic metal silo. In contrast, traditional bags exhibited a significant increase in these parameters. The PICS and SGP bags also exhibited the lowest numbers of total insect pests after 6 months, while the jute bags had the highest infestation. Common insect species found in the stored chickpea seeds were Callosobruchus chinensis (L.), Sitophilus oryzae (L.), and Tribolium confusum (duVal). Furthermore, hermetic bags (PICS and SGP) demonstrated the least grain damage and weight loss, while jute bags had relatively higher values. Seed viability was well maintained in hermetic bags but significantly decreased in traditional bags. Overall, hermetic storage technologies, such as the PICS and SGP bags, effectively suppressed insect development, reduced losses, and preserved seed viability without the need for insecticides. It is recommended that farmers use these hermetic storage bags after proper drying to enhance food security and income generation. By implementing these recommendations, Ethiopia can enhance its chickpea storage practices, reduce post‐harvest losses, and contribute to improved food security and economic sustainability in the chickpea sector. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The excessive use of synthetic pesticides has detrimental impacts on humans, non-target organisms, and the environment. Insect pest management strategies are shifting toward biopesticides, which can provide a feasible and environmentally friendly green solution to the pest problem. The key objective of the present research work was the preparation of Mentha piperita-based nanobiopesticides with enhanced stability, solubility, and pesticidal potential. Nanobiopesticides based on the Mentha piperita extract were prepared using the antisolvent precipitation method. The central composite design of response surface methodology (RSM) was utilized to optimize different process parameters, e.g., the amounts of the stabilizer and plant extract. The nanosuspension of Mentha piperita prepared with the stabilizer SLS showed a particle size of 259 nm and a polydispersity index of 0.61. The formulated biopesticides in the form of nanosuspensions showed good antibacterial activities as compared to the Mentha piperita extract against two phytopathogenic bacterial strains, Clavibacter michiganensis and Pseudomonas syringae. The M. piperita nanosuspension had higher antifungal efficacy against A. niger and F. oxysporum than the Mentha piperita extract. The M. piperita extract and its nanosuspensions were tested for pesticidal activity against the stored-grain insects Tribolium castaneum and Sitophilus oryzae. Mentha piperita-based nanobiopesticides demonstrated significantly high (p  <  0.05) average mortality of 84.4% and 77.7% against Tribolium castaneum and Sitophilus oryzae, respectively. Mentha piperita-based nanobiopesticides showed enhanced pesticidal potential and could be used as a good alternative to synthetic chemical pesticides. [ABSTRACT FROM AUTHOR]

In order to explore the influence of stored cereal volatiles on the behavior of Sitophilus oryzae, the olfactory responses of adult rice weevils to the volatiles of different rice cultivars [Red brown rice (RBR), Daohuaxiangmi (DHXM), Baishuigongmi (BSGM), Yashuixinmi (YSXM), and white glutinous rice (WGR)] were studied using electroantennography (EAG) and behavioural bioassays in different types of olfactometers. S. oryzae showed significantly different preferences for these rice cultivars, in the order RBR > DHXM = YSXM ≥ BSGM > WGR. Furthermore, 26 components were identified in the volatile profile of RBR. Nonanal (29.37%), hexanal (16.08%), and 1-octen-3-ol (8.83%) were the most abundant compounds. EAG recordings showed that the antennae of S. oryzae were able to perceive these three compounds in a dose-dependent manner. The compounds elicited significant EAG responses at various concentrations, with the strongest responses at 100 μg μL−1. S. oryzae had a significant positive behavioural response to nonanal, hexanal, and 1-octen-3-ol at various concentrations, with the most attractive being 50, 100, and 100 µg µL−1, respectively. The olfactory preferences of S. oryzae, based on a comparison of these compounds at their optimal concentrations, were nonanal > 1-octen-3-ol = hexanal. These results indicated that the volatiles of the preferred rice cultivar (RBR) were perceived by the peripheral olfactory system of S. oryzae adults and individually elicited positive chemotaxis. These findings offer new insights into the mechanism of host preferences of stored-grain pests. Nonanal showed the greatest potential for use as a novel monitoring and control tool against this storage-beetle pest. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Taiwan Agricultural Research is the property of Taiwan Agricultural Research Institute, Council of Agriculture, Executive Yuan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Plant Protection & Pathology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Insects living in nutritionally poor environments often establish long-term relationships with intracellular bacteria that supplement their diets and improve their adaptive and invasive powers. Even though these symbiotic associations have been extensively studied on physiological, ecological, and evolutionary levels, few studies have focused on the molecular dialogue between host and endosymbionts to identify genes and pathways involved in endosymbiosis control and dynamics throughout host development. Results: We simultaneously analyzed host and endosymbiont gene expression during the life cycle of the cereal weevil Sitophilus oryzae, from larval stages to adults, with a particular emphasis on emerging adults where the endosymbiont Sodalis pierantonius experiences a contrasted growth-climax-elimination dynamics. We unraveled a constant arms race in which different biological functions are intertwined and coregulated across both partners. These include immunity, metabolism, metal control, apoptosis, and bacterial stress response. Conclusions: The study of these tightly regulated functions, which are at the center of symbiotic regulations, provides evidence on how hosts and bacteria finely tune their gene expression and respond to different physiological challenges constrained by insect development in a nutritionally limited ecological niche. C-ALjyaRxUENP7MJ-64adU Video Abstract [ABSTRACT FROM AUTHOR]

Copyright of Arab Journal of Plant Protection is the property of Arab Society for Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Plant Protection & Pathology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The traditional manual sampling method for detecting stored grain insect pests is labor-intensive and time-consuming, often yielding non-representative samples. However, to achieve more accurate monitoring, it is necessary to understand the distribution patterns of different insect pests within grain silo and their correlation with monitoring and sampling data. This study aimed to assess the population density and distribution of Sitophilus oryzae (rice weevil) in bulk wheat grain to predict insect dynamics effectively. Utilizing a probe trap in a wheat silo, adult insects were tracked across different population densities. The traps recorded captured pests, alongside temperature and humidity data. The correlation analysis revealed that rice weevils were active throughout the silo but less prevalent at the bottom, with the highest distribution near the upper surface. Temperature and humidity significantly influenced their activity, particularly within the 22 °C to 32 °C range. Higher population densities correlated with increased relative humidity, impacting weevil activity. Trapping data aligned with overall population density changes in the silo. This study will provide an accurate assessment of the population density of adult rice weevils in grain silos based on temperature changes in the upper part of the grain silo.

Simple Summary: This study investigated the effectiveness of combining spinosad and alpha-cypermethrin against major wheat storage pests, including Rhyzopertha dominica, Tribolium castaneum, Cryptolestes ferrugineus, Sitophilus oryzae, Oryzaephilus surinamensis, and Trogoderma granarium. Spinosad was tested at two concentrations and alpha-cypermethrin was used at one concentration in laboratory conditions. The results show that combining both treatments led to higher pest mortality compared to individual treatments. The most effective treatment combination was the application of the high dose of spinosad with alpha-cypermethrin, resulting in the highest mortality and substantial progeny reduction. Trogoderma granarium was found to be the most tolerant pest, followed by O. surinamensis, C. ferrugineus, T. castaneum, S. oryzae, and R. dominica. This study suggests that combining alpha-cypermethrin and spinosad can be an effective strategy for protecting stored wheat against multiple insect pests. The deterioration of stored wheat due to pest infestations is a significant concern, with pests like Rhyzopertha dominica, Tribolium castaneum, Cryptolestes ferrugineus, Sitophilus oryzae, Oryzaephilus surinamensis, and Trogoderma granarium being major contributors. This study examined the efficacy of spinosad and alpha-cypermethrin, individually and in combination, against these pests under laboratory conditions. Spinosad was tested at two concentrations (0.05 and 0.1 mg/kg), while alpha-cypermethrin was applied at 0.05 mg/kg. The combined application of both insecticides led to significantly higher pest mortality compared to single treatments. Importantly, all treatments caused substantial pest mortality and exhibited the ability to suppress pest progeny production over time, as observed in both laboratory and persistence trials. Among the various treatment combinations, the joint application of 0.1 mg/kg spinosad and 0.05 mg/kg alpha-cypermethrin emerged as the most effective, resulting in elevated mortality and a marked reduction in pest progeny. Rhyzopertha dominica exhibited the highest susceptibility among the pests, followed by S. oryzae, T. castaneum, C. ferrugineus, O. surinamensis, and T. granarium. The remarkable performance of the joint action of alpha-cypermethrin and spinosad at low doses highlights this combination as an efficacious approach for safeguarding stored grain against these destructive insect pests, warranting further exploration. [ABSTRACT FROM AUTHOR]

The rice weevil, Sitophilus oryzae (Linnaeus, Coleoptera: Curculionidae), is a serious cosmopolitan pest that affects grain in storage and has developed high levels of resistance toward phosphine. In this study, RNA-seq data was used to study the phosphine resistance mechanisms in S. oryzae. Resistant and susceptible populations of S. oryzae were identified based on phosphine bioassays conducted in 32 populations collected across Tamil Nadu, India. Differential expression of mitochondrial (COX1, COX2, COX3, ND2, ND3, ATP6 , and ATP8) and detoxification genes (Cyps , Gsts , and Cbe) were observed in the resistant and susceptible populations of S. oryzae. The previously characterized phosphine resistant gene, dld (dihydrolipoamide dehydrogenase) linked to the rph2 locus, was found to be up-regulated in resistant S. oryzae population (ISO-TNAU-RT) treated with phosphine. Also, the genes involved in Tricarboxylic acid (TCA) cycle were significantly down-regulated. In addition, a significant up-regulation in the expression of the antioxidant enzymes superoxide dismutase (2.5×) and catalase (2.1×) in ISO-TNAU-RT populations was recorded. Furthermore, a distinct amino acid substitution, Lysine > Glutamic acid (K141E) was identified in resistant phenotypes. In silico docking studies of both resistant and susceptible DLD protein with phosphine molecule revealed that the amino acid residues involved in the interaction were different. This suggested that the amino acid substitution might lead to structural modifications which reduces the affinity of the target (phosphine). This study provides insight on the various genes, pathways, and functional mechanisms having a significant role in phosphine resistance in S. oryzae. [ABSTRACT FROM AUTHOR]

Copyright of Revista Daena: International Journal of Good Conscience is the property of Spenta University Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study aimed to determine the effects of three different doses of three thyme essential oils on Sitophilus oryzae (L.) and Sitophilus granarius (L.) (Coleoptera: Curculionidae). The present study was conducted under controlled laboratory conditions (25°C temperature and 65% relative humidity) in 2020. Various thyme varieties (Origanum majorona (L.), Origanum saccatum P.H. Davis, Thymbra spicata var spicata L. ( Lamiaceae)), cultivated in Diyarbakır province ecological conditions were employed in the study. After the 4th day of the experiment, the highest mortality rates (100%) were observed with the highest doses of T. spicata var spicata and O. majarona on S. granarius adults, while the mortality rate was 73.75% with O. saccatum. The LC90 values for T. spicata var. spicata, O. majarona, and O. saccatum were 0.9, 0.1, and 1.3 µl/ml respectively. After the 4th day, 100% S. oryzae adult mortality was observed with higher doses of O. majarona (0.5%; 1% v/v), while 1% (v/v) T. spicata var spicata dose led to a 72.50%, and 1% (v/v) O. saccatum oil dose led to 46.25% mortality. [ABSTRACT FROM AUTHOR]