Stored Grain Research Articles

Insecticidal and Repellent Activity of Essential Oils from Seven Different Plant Species against Tribolium castaneum (Coleoptera: Tenebrionidae).

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is the most destructive pest of stored grain commodities. To control the attack of this insect pest, it is important to develop non-hazardous alternatives to replace fumigants. This study examined the fumigant toxicity and repellent activity of seven essential oils (Chinopodium ambrosiodes, Pinus roxburghii, Zanthoxylum armatum, Lepidium sativum, Azadirachta indica, Baccharis teindalensis, and Origanum majorana) against adult T. castaneum under controlled laboratory conditions. The fumigant toxicity and repellent activities of essential oils were tested using five different doses (62.5, 125, 250, 500, and 1000 µg) in vapour-phase fumigation and four-arm olfactometer bioassays, respectively. In vapor-phase fumigation bioassays, mortality data were recorded after 24, 48, and 72 h. The results showed that C. ambrosiodes and P. roxburghii essential oils are potential fumigants against adult T. castaneum. In repellency bioassays, a one-week-old adult population of T. castaneum was used to test the repellency potential of the essential oils. The results indicated that C. ambrosiodes and P. roxburghii had significant repellency potential against T. castaneum. Overall, we conclude that these essential oils have strong repellent and fumigant properties and can be used as potential repellent compounds to deter the insects.

Assessment of Piper longum L. (Piperaceae) leaves toxicity on the adults of Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae)

BackgroundNumerous insect pests attack stored grains causing both qualitative and quantitative losses. The most damaging pest that infests dry stored produce is the red flour beetle, Tribolium castaneum, a secondary pest of stored goods. This pest, especially in its adult stage, exhibits resistance to chemical insecticides, thereby rendering the traditional pesticides ineffective in controlling it. Phyto-derivatives, which are strong insecticides and also ecologically benign, have gained interest as non-chemical solutions for controlling this pest. Hence, the objective of this study was to investigate the potential of Piper longum leaf extract insecticidal action as an environmentally benign insecticide for the first time against the adults of T. castaneum. In this study, P. longum leaf ethanol extract was tested against the adults of T. castaneum by petri dish bioassay method. Ad hoc studies to verify significant mortality for the initial confirmation of adulticidal activity were conducted for 24 h at different dosages of 62.5, 125, 250, 500 and 1000 mg/L of P. longum leaf ethanol extract. Thereafter, dosages set at 10, 20, 30 and 40 mg/L for the fractions of P. longum leaf ethanol extract were conducted. Prior to this, the leaf extract of this plant was subjected to column chromatography for fractionation. The fractions tested for adulticidal activity were subjected to gas chromatography–mass spectroscopy.ResultsSignificant adulticidal action with 100% adult mortality was observed in ethanol extract of P. longum leaves. Among the fourteen fractions (F0–F13) obtained tested, only fractions, F5, F10 and F13, demonstrated adulticidal activity, and the remaining fractions displayed poor activity. One hundred per cent morality was noted in T. castaneum adults after 96 h at 40 mg/L in F5 and F10, and in F13 at 20 mg/L, and their respective LD50 values were 17.6, 26.6 and 10.0 mg/L. The fractions F5, F10 and F13 contained fatty acids, viz., hexadecanoic acid, dotriacontane and heptacosane in F5; tetradecanoic acid and nonadecanoic acid in F10; and octadecanoic acid, aspartame and tridecanoic acid in F13, revealed through gas chromatography–mass spectroscopy.ConclusionsThe results of the study showed that P. longum ethanol leaf extract revealed significant adulticidal activity and is a promising toxic agent to the adults of T. castaneum. The fatty acids in the ethanolic leaf extract fractions of P. longum could have caused toxicity to the adults of T. castaneum. According to the current literature survey, this is the first research report on the adulticidal activity of P. longum leaf extracts against the adults of T. castaneum.

Traits Underlying Experimentally Evolved Dispersal Behavior in Tribolium castaneum

AbstractDispersal is an important behavior in many animals, with profound effects on individual fitness and the evolutionary trajectories of populations. This is especially true within taxa with particular life-history strategies, for example those that exploit ephemeral habitat. Further, dispersal is commonly seen to be part of behavioral syndromes - suites of traits that covary across behavioral contexts. The red flour beetle, Tribolium castaneum (Coleoptera, Tenebrionidae), is a major post-harvest crop pest responsible for large losses through the infestation of stored grain. In this system dispersal is known to have a strong genetic basis and differential artificial selection on dispersal traits produces strong phenotypic divergence. However, it is unknown which traits are able to rapidly evolve to produce these results, or which behavioral components underlie differences in dispersal. Using replicate lines of T. castaneum previously selected for divergent dispersal behavior, we test for correlated activity and movement patterns, morphology and substrate surface use. We find robustly repeatable associations between the dispersal phenotype and higher activity, straighter paths, larger body size (but not relative leg length) and increased tendency to remain at the surface of fodder. Together our results suggest that dispersal is part of a syndrome of traits in T. castaneum, and must be treated as such when considering the evolution of dispersal in this system, and in attempting to predict and control its spread.

Leveraging long-lasting insecticide-incorporated netting to improve fumigation efficacy against stored product insects.

Long-lasting insecticide-incorporated netting (LLIN) has successfully been used to impair mobility and prevent infestation of stored grain by stored product beetles. Understanding how to integrate LLIN with existing integrated pest management (IPM) tactics, such as phosphine fumigation, can further enhance IPM programs. We used three 110 metric tons (MT) capacity grain bins, and in each, 60 perforated buckets (e.g., miniature silos) were filled with 500 g of uninfested wheat. Miniature silos were protected by LLIN (0.3% α-cypermethrin, Carifend®, BASF), positive control (without insecticide), or negative control (no netting). Half of each treatment was randomly assigned to phosphine fumigation treatment, while the remainder were not fumigated. Monthly samples of 100 g of grain from four silos from each treatment in four blocks from three-grain bins were taken between June and October both in 2022 and 2023. We determined whether phosphine fumigation could be reduced with the use of LLIN over the season. Overall, we found that silos protected with LLIN showed insect dispersal and progeny production that was reduced by 83-99% and 89-99%, respectively, compared with insecticide-free netting and no-netting controls. Additionally, damage in silos was reduced by 37-99% compared with controls. Importantly, the total number of fumigations could be reduced by 68-91% by using LLIN compared with controls. Our study demonstrates that LLIN is consistently effective for existing pest management tactics such as phosphine fumigation in bulk storage structures. © 2024 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

High voltage pulsed electric field: A novel method for killing parasitic eggs on the surface of raisins

Aiming to address the issue of stored grain pests easily breeding during the process of dried fruits in Xinjiang, this study proposes a method and a device for killing raisin parasitic eggs based on a high-voltage pulsed electric field. A one-way test and a Box-Behnken central combination test were conducted to investigate the effects of high-voltage pulsed electric field strength and frequency on the unhatched rate and larval survival rate of Plodia interpunctella eggs on raisin surfaces. The experimental results were qualitatively and quantitatively analyzed using biooptical microscope observation and incubation at constant temperature and humidity post-treatment. The findings revealed that with an output voltage of 22.8 kV, the delivery speed of 0.024 m/s, and the electric field frequency of 3.8 Hz, the unhatched rate of the eggs was 68.14 % while the survival rate of the larvae was 20.36 %. These results can provide new insights for both theoretical development and system implementation regarding the use of high voltage pulsed electric fields for eliminating raisin surface eggs, as well as providing valuable academic references for field crop diseases and pests control strategies.

Evaluation of biologically synthesized zinc oxide nanoparticles from Paecilomyces farinosus on the biology of sawtoothed grain beetle (Oryzaephilus surinamensis)

The sawtoothed grain beetle, Oryzaephilus surinamensis, is a major pest of stored grains such as rice, wheat, barley, and legumes. This insect is highly adaptable and poses a persistent threat in diverse climatic conditions and storage environments. The present study aimed to determine the effect of the fungus Paecilomyces farinosus on the life stages (eggs, second and fourth instar larvae, and 24-hour-old pupae) of O. surinamensis. The fungus was tested at spore densities of 3×10⁷, 3×10⁵, and 3×10³ spores/ml. The results showed that the highest mortality rates for eggs, second instar larvae, fourth instar larvae, and 24-hour-old pupae at a concentration of 3×10⁷ spores/ml were 40.3%, 58.7%, 39.01%, and 55.6%, respectively. Furthermore, the study evaluated the impact of nano-zinc oxide (ZnONPs) on O. surinamensis at concentrations of 3000, 2000, and 1000 ppm. Various characteristics of the prepared ZnONPs, such as shape, size, and maximum absorption by ultraviolet spectroscopy, were analyzed. The results indicated 100% mortality of eggs treated with concentrations of 3000 ppm and 2000 ppm. The highest mortality rates for second instar larvae and 24-hour-old pupae were 80% and 20%, respectively, at a concentration of 2000 ppm. For fourth instar larvae, the highest mortality rate was 68.22% at a concentration of 3000 ppm. The study demonstrated that ZnONPs at all tested concentrations were more effective than the fungal suspension in causing mortality of eggs and second and fourth instar larvae. Moreover, the germination rate of rice grains treated with direct spraying was not affected by any of the treatments.

Insecticidal Properties of Curcuma longa on the Growth of Prostephanus truncates

Prostephanus truncatus, a devastating pest, causes significant damage to stored grains. Synthetic insecticides pose environmental and health risks, necessitating eco-friendly alternatives. Curcuma longa, a medicinal plant, exhibits insecticidal properties. This study investigates the effect of Curcuma longa on the growth of Prostephanus truncatus. Results show that Curcuma longa extracts significantly inhibit the growth and development of Prostephanus truncatus, offering a promising natural insecticide.

Volatile Organic Compounds Produced by Bacillus sp. Strain R2 Inhibit Aspergillus flavus Growth In Vitro and in Unhulled Rice.

Volatile organic compounds (VOCs) produced by Bacillus species exhibit biocontrol activity against fungal pathogens of fruits and vegetables. However, research on the effect of VOCs on Aspergillus flavus in stored grains is limited. This study aimed to investigate the effects of VOCs extracted from the strain R2, which was isolated from unhulled rice and identified as Bacillus paramycoides on A. flavus in vitro and unhulled rice. R2 VOCs effectively inhibited conidial germination and the hyphal growth of A. flavus in vitro. Moreover, R2 VOCs reduced the fungal population, aflatoxin B1 (AFB1) levels, and free fatty acid (FFA) value by 90.8%, 67%, and 38.7%, respectively, in unhulled rice. Eighteen R2 VOCs were identified using headspace solid-phase micro-extraction gas chromatography-mass spectrometry, and the individual activity of the VOCs against A. flavus was tested in vitro. Benzaldehyde (Ben) and 3,7-dimethyl-1-octanol (Dmo) showed strong inhibitory activities against A. flavus on PDA plates, with inhibition rates of 100% and 91.2%, respectively, at a concentration of 20 μL/dish. Ben at the concentration of 0.09 mg/mL, Dmo at the concentration of 0.07 mg/mL, or a mixture of both at halved concentrations could reduce the fungal population, AFB1 levels, and FFA content in unhulled rice. Our findings suggest that R2 VOCs are good alternatives to traditional chemical fumigants for suppressing A. flavus in stored grains. However, further research is necessary to establish the optimal fumigation concentration of these two components in unhulled rice. The impact of their residues on grain quality should be explored through sensory evaluation and nutritional analysis, and their safety to the environment and human body should be evaluated through safety assessment.

Evaluating the Efficacy of Plant Extracts in Managing the Bruchid Beetle, Callosobruchus maculatus (Coleoptera: Bruchidae).

An estimated 2000 plant species have been employed for pest control worldwide. The use of these botanical derivatives is thought to be one of the most cost-effective and sustainable options for pest management in stored grain. The present study was designed to assess the efficacy of five plant extracts viz; Nicotiana tabacum L., Nicotiana rustica L., Azadirachta indica A. Juss., Thuja orientalis L., and Melia azedarach L. against Callosobruchus maculatus L. Plant species extracts were applied at six different concentrations, i.e., 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0% in four replications. The phytochemical analyses of ethanolic extracts of five plant species showed variable amounts of phytochemicals i.e., alkaloids, flavonoids, saponins, diterpenes, phytosterol, and phenols. Total phenolic and flavonoid compounds were also observed. The efficacy of A. indica was highest, characterized by the lowest infestation rate (16.65%), host seed weight loss (7.85%), mean oviposition (84.54), and adult emergence (58.40%). In contrast, T. orientalis was found to be the least effective against C. maculatus, with the highest infestation rate of 25.60%, host seed weight loss of 26.73%, mean oviposition of 117.17, and adult emergence rate of 82.01%. Probit analysis was performed by estimating LC50 and LC90. The toxicity percentages of N. tabacum (LC50 = 0.69%, LC90 = 14.59%), N. rustica (LC50 = 0.98%, LC90 = 22.06%), and A. indica (LC50 = 1.09%, LC90 = 68.52%) were notable in terms of the lower LC50 and LC90 values after the 96-h exposure period against C. maculatus. Repellency was assessed by using the area preference and filter paper method. The repellency of C. maculatus on plant extracts increased with the increasing dose and time, such that it was the highest after 48 h. Likewise, at a 3% concentration, A. indica demonstrated 100.00% (Class-V) repellency followed by N. tabacum (96.00%, Class-V), N. rustica (74%, Class-IV), M. azedarach (70.00%, Class-IV), and T. orientalis (68.00%, Class-IV). Based on the findings of this study, we recommend integrating N. rustica, N. tabacum, A. indica, and M. azedarach for effective management of C. maculatus and highlight the potential of these plant species in the formulation of new biocidal agents.

The effectiveness of phosphine fumigation of wheat in a farm-scale thermosyphon silo

Fumigation of pests is essential for maintaining the quality of stored grain. Rapid and effective pest control is the key to minimise damage to the valuable grain. The current study investigated the efficiency of a farm-scale thermosyphon silo to passively circulate phosphine fumigant gas by measuring the phosphine concentrations at a series of points throughout the silo. A 50 tonne sealable grain silo with an external thermosyphon was fitted with gas sampling lines at three different levels in the grain body, and also in the headspace. The grain was fumigated with phosphine gas 12 times over a 12 month period to contrast the thermosyphon system efficiency under varied external environmental conditions. The minimum fumigation standards of 200 ppm for 10 days or 300 ppm for 7 days were reached and exceeded in all fumigation cycles throughout the year in 12.5–22 days, demonstrating the effectiveness of the thermosyphon system. In addition, the final fumigation was held until the phosphine concentration dropped to 200 ppm. The silo reached 200 ppm only four days after fumigation, reached a maximum of approximately 600 ppm after 30 days, and did not fall below 200 ppm until 106 days after fumigation. Linear air velocity in the was also measured in the thermosyphon pipe and showed that airflow could reach as high as 2.7 m/s, but flow was sporadic and not consistent, most likely due to pressure build up on the headspace of the silo due to resistance to airflow by the bulk grain body. Temperature and humidity results indicated that while both parameters are fundamental in the production of phosphine from aluminium phosphide tablets, they work against each other. This provides an effective control mechanism that prevents the rapid production of phosphine, thereby reducing the buildup of phosphine and reducing the risk of an explosion.

Synthesis and application of biodegradable seed coatings to assess the infestation of chickpea (Cicer arietinum L.) seeds by pests

Pulses such as chickpeas face significant damage caused by pests during their growth and storage. The overuse of synthetic pesticides on seeds requiring several cycles of active ingredient applications results in increased expenses and environmental risks by contaminating soil, water, and air. These risks of seed damage without use of harmful pesticides can be reduced by coating the seeds with biodegradable seed coatings. The objective of the study was assessing the effectiveness of biodegradable seed coating in managing stored grain pests and to examine its effects on the germination of chickpeas. For this study chickpea (Cicer arietinum L.) seeds were coated with biodegradable coatings like polyvinyl alcohol with multinutrients, neem oil, chitosan and mucilage-starch nanocrystals. The characterization of coatings was carried out using Fourier Transform Infrared Spectroscopy, X-ray Diffraction and Scanning Electron Microscope. Germination of coated and uncoated chickpea seeds was observed by paper-towel method after 5 and 10 days. Chitosan coated seeds had greatest root length (3.10 ± 0.05 cm), shoot length (3.93 ± 0.08 cm), dry weight (0.24 ± 0.05 g), fresh weight (0.43 ± 0.05 g), germination rate (98.87 %) and vigour index (639.09 ± 0.05) followed by polyvinyl alcohol with multinutrients coated seeds, mucilage-starch nano crystals coated seeds and control group after ten days. The lowest root length (0.97 ± 0.14 cm), shoot length (1.53 ± 0.12 cm), dry weight (0.1 ± 0.005 g), fresh weight (0.21 ± 0.14 g), germination rate (65 %) and vigour index (163.75 ± 4.72) were displayed by neem oil-coated seeds. The impact of stored grain pests was evaluated and it was shown that neem oil had the highest efficacy in controlling pulse beetle infestations followed by chitosan, polyvinyl alcohol with multinutrients and mucilage-starch nano crystals. Neem oil coating enhanced pest mortality by 95 % after 15 days, reduced seed damage by 16.3 % and minimized seed weight loss by 10.6 % after 30 and 45 days. Biodegradable seed coating is a cost-effective and environment friendly way to improve seed performance and protect crops sustainably.

Identification and Prevalence of Fungal Species in Stored Sorghum Grains Surveyed at Bodija and Oyo Town Markets in Oyo State and Ikire and Iwo Town Markets in Osun State, Western Nigeria

This study investigated the identification and prevalence of fungal species in stored sorghum grains surveyed at Bodija and Oyo town markets in Oyo State and Ikire and Iwo town markets in Osun State, Western Nigeria using appropriate standard methods. Six distinct fungal species were isolated from the sorghum grains and identified through macroscopic and microscopic examination. These species included Aspergillus flavus, A. niger, A. tamarii, A. terreus, Fusarium sp., and Rhizopus stolonifer. The prevalence of fungal contamination was found to be higher in the markets of Oyo State compared to those in Osun State. Additionally, Aspergillus flavus and A.niger were the most prevalent fungal species, while Rhizopus stolonifer was the least prevalent.

Graphene powders as new contact nanopesticides: Revealing key parameters on their insecticidal activity for stored product insects

The overuse and reliance on pesticides has caused insects to develop resistance with global concerns. To address this problem extensive research is directed to find new and sustainable alternatives using chemical-free and resistance-free solutions for pest control. This paper presents a comprehensive investigation of the insecticidal properties of several types of industrially produced graphene powder materials such as graphene and graphene oxide (GO) with micro- and nano size and different structural and chemical properties as new contact nanopesticides against three major stored grain insects: the rice weevil Sitophilus oryzae (L.), the lesser grain borer, Rhyzopertha dominica (F.)˙ and the larger grain borer, Prostephanus truncatus Horn. Bioassays were performed using different concentrations, i.e., 0, 100, 500 and 1000 ppm of graphene powders on the mortality of selected adult insects recorded after 3, 7, 14, and 21 days of exposure and progeny production after 65 days. Results showed that graphene oxide (GO) has no insecticidal efficacy while graphene powders with nano-size particles showed significantly enhanced insecticidal performance compared to micron-size graphene powders. The observed insecticidal effects are explained by the higher probability that nano-sized graphene particles adhere on the insect body compared to large particles. The mortality is proposed as the result of physical mode of action of attached graphene nanoparticles causing stronger interruption of the protective cuticle layer, gas respiratory functions and faster mortality. The findings of this study revealed that it is important to select graphene materials with optimal structural and interfacial properties to achieve the highest insecticidal performance in potential development of a new generation of sustainable insecticides.

Studies on the Response of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) to Multicolour Light System

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) commonly known as rust red flour beetle was a universal pest of stored produce with an extensive feeding diversity. The management of T. castaneum in field conditions was through fumigation and spraying of suitable insecticides. Even though many plant products were found effective against pests in invitro conditions, they could not be mixed with the stored produce for fear of losing the table quality. Physical forces seemed to be good alternatives to chemical treatment as far as stored grain pests were concerned. The use of gamma and UV radiations, microwaves and ultrasonic sound waves against T. castaneum and other stored grain pests had been tried by many authors. The objectives of this study were to check the adult beetles and final instar grubs of T. castaneum to different colours of light and it showedpreference for clear tungsten (white) light, while they were averse to red coloured light. This trend was explicit even after the entrainment of beetles to red colour light for further generations. Based on these results it could be presumed that T. castaneum adults preferred to move away from red coloured light. By changing the colour of bright light to dark lighting in warehouses, it could be possible to manage T. castaneum in small measure. Total eradication of stored product pests like T. castaneum was at least possibility and the selection of a proper management system could help to solve the stored produce pest problem to a greater magnitude.

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.

Species Composition and Diversity of Stored Grain Pests in Fortified Rice Collected from Different Districts of Telangana State, India

A study was conducted to measure the species composition and diversity of various stored grain insect pests in fortified rice collected from different districts of Telangana,India during 2023-2024. Theresults indicated that a total of six species of stored grain insects belonging to three orders viz., Coleoptera (3), Lepidoptera (2) and Psocoptera (1) were recorded in fortified rice. The six insect species were rice weevil, Sitophilus oryzae, Saw toothed beetle, Oryzaephilus surinamensis, redflour beetle, Tribolium castaneum, Angoumois grain moth, Sitotroga cerealella, rice moth, Corcyra cephalonica and pscocids. Among all these insects highest population of O. surinamensis was recorded in four districts of Telangana except in Ranga reddy and Nalgonda. The diversity indices indicated that Shannon-weiner diversity index (H) was high in Warangal district samples(H=1.426) while the Jagtial population recorded highest Margalef’s species richness index (R=1.27). The highest Pielou’s evenness index was reported from Nalgonda district (e=75), and Simpson diversity index of stored grain pests was found to be maximum (0.718) in Warangal district rice samples. The knowledge on species composition and diversity helps in planning timely management strategies for stored grain pests.

Correlation Analysis of Sitophilus oryzae (Linnaeus) Real-Time Monitoring and Insect Population Density and Its Distribution Pattern in Wheat Grain Piles

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.

Effectiveness of Agricultural Waste Ashes in Controlling Sitophilus oryzae Infestation in Stored Rice Grains

In this study, the insecticidal effectiveness of agricultural waste ashes of sawdust, rice husk, groundnut shell, maize cob, and wheat straw against Sitophilus oryzae in stored rice grains was investigated. The research, conducted to assess grain damage, weight loss, and weevil perforation index caused by S. oryzae over intervals of 30, 60 and 90 days. The ashes were applied at a rate of 2 gm per 100 gm of grains. Over a 90-day period the untreated control exhibited the highest grain damage (33.80%) and weight loss (14.23%). Among ash treatments, sawdust ash resulted in the highest grain damage (18.40%) and weight loss (12.47%), whereas groundnut shell ash was the most effective, showing the lowest grain damage (12.87%) and weight loss (8.53%). The chemical insecticide Chlorpyrifos 48EC maintained complete protection with 0% grain damage and weight loss. The Weevil Perforation Index (WPI) was significantly lower in groundnut shell ash (9.27) compared to other ash treatments, emphasizing its effectiveness in preserving rice quality.

Static analysis of semi‐underground double‐storey squat silo

AbstractThe semi‐underground double‐storey squat silo (SUDSSS) is a new type of silo with the advantages of preserving grain quality. In this paper, a numerical model of SUDSSS was constructed using solid elements. The proposed numerical model was validated by test results of an experimental underground silo, and the results demonstrated that: (1) Before and after backfilling, the radial and circumferential stress of the underground storey reached their maximum at 2/3 from the bottom and 2/3 from the ground surface, respectively; (2) As the height of grain storage increases, the silo wall stress in the overground storey increases. From the top of the underground storey up to 1/4 height of the overground storey, the stress of silo wall increases. (3) For the underground storey, the maximum stress occurs at 1/3 of the way from the apex of bottom cone.Practical applicationsThe semi‐underground double‐storey squat silo is a new grain storage device proposed by this paper, which consists of two layers. The lower layer is located in the ground and can utilize the shallow ground temperature to realize the green and low‐temperature storage of grain, the upper layer is conducive to the turnover of grain, which can ensure the quality of grain storage. The new silo has the advantages of saving land, energy saving and carbon reduction. Based on the silo, this paper investigates the stress–strain properties of the silo before and after soil backfilling during the construction stage, and obtains the change pattern of the static mechanical properties of the silo. This paper analyses the mechanical properties of semi‐underground double‐storey squat silo under different storage conditions at the grain storage stage, and studies the change patterns of the mechanical properties of the silo body under different storage heights.

Níveis de CO2, quebra técnica e qualidade dos grãos de milho armazenados em diferentes condições

ABSTRACT The use of CO2 sensors has been reported as an effective tool in the early detection of signs of deterioration, allowing good accuracy in decision-making about the quality of stored grains. The objective of this study was to quantify the CO2 levels produced by maize grains stored at ambient temperature in a prototype silo, with initial moisture contents of 14, 16 and 18% w.b., and to evaluate the quality of the product over time and the technical breakage. Analyses of moisture content, ash, proteins, lipids, Hue Angle (color), germination and electrical conductivity were performed. Inside the silos, the amount of CO2, relative air humidity and temperature were monitored every hour. Grain quality evaluations were carried out at four storage times (0, 30, 60 and 90 days). A completely randomized design in a 3 × 4 factorial scheme with six replicates was used. Grains with higher moisture contents showed higher technical breakage and losses associated with CO2 emissions. Moisture content, protein, lipids, germination, bulk density, lightness and chroma decreased over time, while the electrical conductivity increased, resulting in greater damage to membranes and loss of quality of maize grains. Monitoring of CO2 in the grain mass is a good tool to assess the quality of grain, and higher initial moisture content caused greater level of CO2 emission and reduction in quality of maize grains.